[sci.electronics] Mercury Filled Speaker Wire

bmaraldo@watdcsu.UUCP (01/01/70)

  And how about the crystal structure?  THERE ISN'T ONE in mercury!  It is
  know that linear crystal (lon crytal) configuration wire propagates a
  signal with more linear accuracy.  In the mercury cables there is now
  crystal stucture and this is material dependent.

				The Audiophile



-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

ejm@mas1.UUCP (Eric Mattern) (01/01/70)

>
>
>				I'm an audiophile and I hate CD's and I'm
>				damn proud of it!  So there!  NAA!
>
>				Brett L Maraldo





	      I'm with you !!!


	      rick


		 

bblue@crash.CTS.COM (Bill Blue) (01/01/70)

In article <1222@pinney.munsell.UUCP> pac@pinney.UUCP (Paul Czarnecki) writes:
>In article <1709@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:
>>In my view, the big culprit that kills the 'hardware store' variety
>>cables is the varying time of arrival of different frequencies at the
>>other end of the cable due to skin effect propagation and other factors.
>
>>I make these statements from personal experience with all sorts of
>>cables.  Take *any* heavy, stranded, copper cable -- anything from 12/2
>>or 10/2 electrical cable to the 12 guage (standard) Monster cable
>>(reasonably cheap at ~$.50/foot) and you'll get a similar sound.  The
>>number of strands and thickness of each will provide subtle differences,
>>but all in all they're about the same.
>
>Why must you use stranded cable?  I realize the mechanical
>difficulties in using a solid core cable but are there any electrical
>problems?
>
>I used 12 gauge solid core for many years.  It was the cheapest stuff
>I could find.  (It was UL listed for underground use also. :-)

I've tried that too - 12/2 in fact, though it wasn't UG.  I even tried
it once in a studio between the monitors and power amp to see what the 
reaction from other engineers would be and if that reaction was similar
to mine.  It was. I had observed that with 12 gauge solid, there was an
extreme loss of high frequency detail.  It was replaced with sort of a
soft haze, not offensive but very vague.  The lower octave (kick drum,
etc) seemed to all but disappear as well.  I was an engineer at the time
(early 70's) when I performed this experiment.  All of us (myself and
two others) concluded in separate recording sessions (our own clients)
that our ability to equalize and balance the various tracks was
seriously impaired.  In tests repeated recently, the same differences
are heard, but with higher grades of speaker cables becoming available,
the differences are much greater.

I believe the big problem with large gauge solid conductor cable is
skin effect related.  The diameter is simply too large for reasonable
handling of high frequencies.  In the above tests which, by the way,
were long before there were any 'audiophile' cables, we found that
moderately heavy gauge, stranded, non-plated soft copper wire was by far
the most revealing.  Now this was about '72 -- with many so-called
audiophiles in '87 still poo-pooing the sound of cables -- imagine the
kinds of comments this topic produced back then?


It always has struck me rather funny when engineer types (not recording
but electronics) go into long dissertations on how we audiophiles can't
be hearing differences in so-and-so cables, or capacitors, or resistors,
or (gasp) power supplies, and spout streams of numbers and other
specifications that 'prove' such things don't apply to audio
frequencies.  Years later though, when it becomes generally accepted
that such things do in fact make audible differences, the same engineers
not only agree that these things do make a difference, but can spout
reasons why.  I guess all it really has to do with is your current
levels of understanding and awareness -- both of what quality audio
really can sound like (unless you've experienced it, it's indescribable)
and technically in how you associate formulas and specs to the real
world.

--Bill

bmaraldo@watdcsu.UUCP (09/10/87)

  Is there such a product on the market?

  I just made a set of 2m long 5mm in diameter mercury filled cables with
  copper touch conductors and large lugs.  I really do not have a clue as
  to the dynamic characteristics of mercury.  If you know anything about
  what an audio signal might look like after propagating through such a
  cable, I'd like to know, especially if you have data to back your
  comments up with.  I already know about the resistivity of Mercury;  it
  is about 95 microhms-cm at 20C (Copper is 1.7 microhms-cm).  My
  calculations show that each 2m Mercury conductor has a resistance of 15
  milliohms and that a 10gauge copper wire 3mm in diameter has a resistance
  of 0.1 milliohms (these are approximate theoretical values and do not
  represent measured data).

				Brett L Maraldo


-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

koko@uthub.UUCP (09/10/87)

In article <3816@watdcsu.waterloo.edu>, bmaraldo@watdcsu.waterloo.edu
(Commander Brett Maraldo) writes:
> 
> 
>   Is there such a product on the market?
> 
>   I just made a set of 2m long 5mm in diameter mercury filled cables with
>   copper touch conductors and large lugs.  I really do not have a clue as
>   to the dynamic characteristics of mercury.

Metals are metals.  Electricity flows in the same way through all metals.
This includes copper and mercury.

>                                               If you know anything about
>   what an audio signal might look like after propagating through such a
>   cable, I'd like to know, especially if you have data to back your
>   comments up with.

You have been reading too many audiophile magazines.  As far as audio
frequencies are concerned, no cables of typical length (i.e. fitting in
your living room) are going to behave like transmission lines.  Therefore,
the conductor material, wire configuration and spacing, and insulation
material are all irrelevant.  So audio signals will look the same on
copper cables as on mercury ones.

>                      I already know about the resistivity of Mercury;  it
>   is about 95 microhms-cm at 20C (Copper is 1.7 microhms-cm).  My
>   calculations show that each 2m Mercury conductor has a resistance of 15
>   milliohms and that a 10gauge copper wire 3mm in diameter has a resistance
>   of 0.1 milliohms (these are approximate theoretical values and do not
>   represent measured data).
> 
This is the only significant difference.  I would prefer copper cables because
for larger currents, as typically found in speaker cables, the copper ones will
have less loss.

If they were available on the market, I wouldn't buy mercury cables because
they are not worth the expense and because any mercury leakage would be
hazardous, and would require special equipment for cleanup.

> 				Brett L Maraldo
> 
> 
> -- 
>                --------     Unit 36 Research     ---------
> 	                "Alien Technology Today"
>                -------------------------------------------
> 	                    bmaraldo@watdcsu

palmer@tybalt.caltech.edu (David Palmer) (09/10/87)

In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>
>  I just made a set of 2m long 5mm in diameter mercury filled cables with
>  copper touch conductors and large lugs.

Forgive me for asking, but WHY?

If you were really into exotics, you would make up a batch of superconducting
speaker cable, now that it needs only liquid nitrogen. :-)  Of course that
would only be unique for a year or so before EVEYBODY had them at room
temperature, but if you kept the old system, you could talk about the audible
differences due to lower thermal noise.

		David Palmer
		palmer@tybalt.caltech.edu
		...rutgers!cit-vax!tybalt.caltech.edu!palmer
	The opinions expressed are those of an 8000 year old Atlantuan
	priestess named Mrla, and not necessarily those of her channel.

heuring@boulder.Colorado.EDU (Vincent Heuring) (09/10/87)

In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>
>  I just made a set of 2m long 5mm in diameter mercury filled cables with
>  copper touch conductors and large lugs.
>

I can see the review by Anthony Cordesman now:

	"This wire lends a liquid transparency to strings. The fluid quality
	of horns has to be heard to be believed.  There is a silvery
	quality to the brass, with no sign of the hard-edged, coppery
	sound normally associated with speaker cable...


| Vincent Heuring				|
| Dep't of Electrical & Computer Engineering	|
| University of Colorado - Boulder		|
| heuring@colorado.EDU				|

bmaraldo@watdcsu.UUCP (09/11/87)

In article <578@uthub.toronto.edu> koko@uthub.toronto.edu (M. Kokodyniak) writes:
> Metals are metals.  Electricity flows in the same way through all metals.
> This includes copper and mercury.
> 
   Crap.  Then there should be no difference between coaxial cable, twisted
   pair and transmission lines in terms of signal propagation.  BUT THERE
   IS!

> You have been reading too many audiophile magazines.  As far as audio
> frequencies are concerned, no cables of typical length (i.e. fitting in
> your living room) are going to behave like transmission lines.  Therefore,
> the conductor material, wire configuration and spacing, and insulation
> material are all irrelevant.  So audio signals will look the same on
> copper cables as on mercury ones.
   
   Again: Crap.  What you have said here is simply a matter of opinion.  I
   can hear differences between audio cables.  I can not report and
   differences under controlled double-blind tests because I have never
   taken part in one.  I am not attempting to convince you that I can hear
   a difference, but what I hear is good enough for me.

				Brett L Maraldo




-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

dave@micropen (David F. Carlson) (09/11/87)

> In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
> >
> >  I just made a set of 2m long 5mm in diameter mercury filled cables with
> >  copper touch conductors and large lugs.

I hope you cables are *very* well sealed.  Mercury is a very hazardous substance
to expose yourself and your family to for no good reason.  Long term and short
term exposure hazards are well documented and just the vapor leakage from 
whatever cable packaging should be considered a potential hazard.  Exercise
extreme caution.  Again:  no good reason.

-- 
David F. Carlson, Micropen, Inc.
...!{seismo}!rochester!ur-valhalla!micropen!dave

"The faster I go, the behinder I get." --Lewis Carroll

ron@topaz.rutgers.edu (Ron Natalie) (09/11/87)

> > Metals are metals.  Electricity flows in the same way through all metals.
> > This includes copper and mercury.
> > 
>    Crap.  Then there should be no difference between coaxial cable, twisted
>    pair and transmission lines in terms of signal propagation.  BUT THERE
>    IS!

You are both arguing different sides of the picture.  In the Copper Vs.
Mercury debate, there is essentially no difference other than resistance.
So the material there is unimportant.  The difference indicated about
coax v. twisted pair v. transmission lines (shows an inadequate knowledge
of the subject right there, transmission lines do not belong in a group
with examples of themselves).  Theoretically, if you had the same resistance,
dialectric, and relative conductor spacings (and shape) you'd get the same
performance regarless of what the conductor was made of.

rck@ihuxv.ATT.COM (R. C. Kukuk) (09/11/87)

In article <2166@sigi.Colorado.EDU>, heuring@boulder.Colorado.EDU (Vincent Heuring) writes:
> In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
> >
> >  I just made a set of 2m long 5mm in diameter mercury filled cables with
> >  copper touch conductors and large lugs.
> >
> 
> I can see the review by Anthony Cordesman now:
> 
> 	"This wire lends a liquid transparency to strings. The fluid quality
> 	of horns has to be heard to be believed.  There is a silvery
> 	quality to the brass, with no sign of the hard-edged, coppery
> 	sound normally associated with speaker cable...
	However, when the cables are jarred, an echo chamber effect is
	heard as compression waves travel back and forth in the mer-
	cury ...
> 
Ron Kukuk
AT&T Bell Labs

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rdp@teddy.UUCP (Richard D. Pierce) (09/11/87)

In article <3827@watdcsu.waterloo.edu> (Commander Brett Maraldo) writes:
->In article <578@uthub.toronto.edu> (M. Kokodyniak) writes:
->> Metals are metals.  Electricity flows in the same way through all metals.
->> This includes copper and mercury.
->> 
->   Crap.  Then there should be no difference between coaxial cable, twisted
->   pair and transmission lines in terms of signal propagation.  BUT THERE
->   IS!
->

Double crap. He did not say "there is no difference between conductor
configurations" as you contend he did. He said "Electricity flows in the 
same way through all metals," a markedly different statement than what
you contend.

Secondly. crap to your "BUT THERE IS". A far more accurate statement
would be "BUT I (one of THINK, CONTEND, INSIST, BELIEVE, WISH, etc) THERE IS."

The issue of the audibility of wire is far from settled. To insist that
there definitely is a difference without being willing to submit the
contention to fair, unbiased and revealing tests is to beg dismissal of
that contention.

->> You have been reading too many audiophile magazines.  As far as audio
->> frequencies are concerned, no cables of typical length (i.e. fitting in
->> your living room) are going to behave like transmission lines.  Therefore,
->> the conductor material, wire configuration and spacing, and insulation
->> material are all irrelevant.  So audio signals will look the same on
->> copper cables as on mercury ones.
->   
->   Again: Crap.  What you have said here is simply a matter of opinion.  I
->   can hear differences between audio cables.  I can not report and
->   differences under controlled double-blind tests because I have never
->   taken part in one.  I am not attempting to convince you that I can hear
->   a difference, but what I hear is good enough for me.
->

Again, double crap. The statement "no cables of typical length are going
to behave like transmission lines [at or near audio frequencies]" is not
a matter of opinion, it is a statement of fact firmly secured in
transmission line mathematics. While I may not agree that "conductor material,
wire configuration and spacing, and insulation material are all irrelevant,"
to criticize your respondant on the basis of a strawman you have set up
is unfair and unproductive.

Commander, you may indeed be able to hear a difference between cables, you
may indeed THINK you hear a difference between cables. There may well BE
a difference between cables. But to declare established fact (tranmission
line performance, etc.) as mere personal opinion simply because it not
only does not support your contentions, but refutes them, demonstrates
ones misunderstanding at the physical processes and possibly some
psycho-acoustic effects as well.

Again, let's argue against the point that someone made, not what you
think someone made.

To add my one two cents woorth to the TECHNICAL discussion, there are a
variety of reasons why mercury is very poorly suited to audio-style
conductors. 

    1.	It has a relatively high bulk resistivity. For a given cross
	sectional area, it is much higher than copper, as you suggested.
	Even per unit mass, it suffers to many other conductors.

    2.	If you think skin effect is an issue, than multi-stranded solid
	conductors will far outperform a single liquid conductor

    3.	Mercury is just plain dangerous stuff.

    4.	If I heard you right when you sain the mercury is in copper
	jacketing, your going to be in for a real big surprise. Copper
	is soluble in mercury. Sooner or later, your little wires are
	going to start leaking. A lot! (take it from someone who had
	to deal with another inane mercury based audiophile product,
	the Keith Monks tone arm.)

    5.	Mercury, when exposed to air, quickly forms a skin of mercuric
	oxide, which present a very non-linear electrical junction with
	whatever interfacing conductor it meets. Most mercury switches
	are hermetically sealed with dry nitrogen or argon to prevent 
	this from happening.

Dick Pierce

larry@kitty.UUCP (Larry Lippman) (09/12/87)

In article <2115@ihuxv.ATT.COM>, rck@ihuxv.ATT.COM (R. C. Kukuk) writes:
> > >  I just made a set of 2m long 5mm in diameter mercury filled cables with
> > >  copper touch conductors and large lugs.
> > 
> > I can see the review by Anthony Cordesman now:
> > 
> > 	"This wire lends a liquid transparency to strings. The fluid quality
> > 	of horns has to be heard to be believed.  There is a silvery
> > 	quality to the brass, with no sign of the hard-edged, coppery
> > 	sound normally associated with speaker cable...
> 	However, when the cables are jarred, an echo chamber effect is
> 	heard as compression waves travel back and forth in the mercury ...

	Actually, you have touched upon a grain of truth.  Mercury-filled
tubing - expecially of the silicone rubber variety - makes a simple, but
effective position transducer.  As the cable is stretched, both the length
of the mercury column increases and its diameter decreases in the affected
area; this results in greater electrical resistance as the tubing is
stretched.  Knowing the elastic modulus of the tubing, its physical dimensions
and the weight of the mercury allow quantitative measurement of stress and
strain.
	Mercury-filled tubing has been used as a stress/position transducer
for a number of years, especially in bio-medical applications as a pneumograph
transducer (respiration measurement using chest expansion) and as a
plethysmograph transducer (limb expansion due to arterial pressure pulse).
	So, I would think that y'all "audiophiles" out there contemplating
the use of mercury-filled cable would, upon further contemplation, reject it
since it would obviously be susceptible to microphonics.

	Now, for a more practicable idea, consider the use of SODIUM-filled
cables, which have been available to the electric power industry for a number
of years.  Sizes go up to at least 500,000 circular mils, and I know for a
fact that the cable is available with an insulation rating of 15 kV for
direct-burial applications.
	Be the first on your block to have sodium-filled speaker cables!
They'll beat ol' Monster Cable any day...

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231       {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}   "Have you hugged your cat today?" 

bmaraldo@watdcsu.UUCP (09/12/87)

In article <14647@topaz.rutgers.edu> ron@topaz.rutgers.edu (Ron Natalie) writes:
> Mercury debate, there is essentially no difference other than resistance.
> So the material there is unimportant.  The difference indicated about
> coax v. twisted pair v. transmission lines (shows an inadequate knowledge
> of the subject right there, transmission lines do not belong in a group
> with examples of themselves).  Theoretically, if you had the same resistance,
> dialectric, and relative conductor spacings (and shape) you'd get the same
> performance regarless of what the conductor was made of.

  This is true, but we DO NOT have the same resistance.  Infact, the
  resistance differs by about a magnitude.  Will this not change the
  dynamic signal characteristics of the conductor?  How is skin effect
  handled (in the same manner as copper, perhaps?)?  Impedance?  Answer
  these questions for me and I'll be grateful, but do supply scientific
  explanations as the intuitive explanations I've been getting just don't
  cut it.

  As for why I made the cables (every mail message I've been getting on the
  topic has asked WHY):  It seemed like a neat thing to do.  The cables
  certainly look great and they actually work well.  I would have thought
  that this little project would have been looked apon with interest but
  the opposite is true.  As soon as anyone gives mention to any audiophile
  trait (ie. cables sounding different) flames start to fly.  What do you
  people listen to, JVC and Sony equipment?!?


				I'm an audiophile and I hate CD's and I'm
				damn proud of it!  So there!  NAA!

				Brett L Maraldo




-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

bblue@crash.CTS.COM (Bill Blue) (09/12/87)

In article <578@uthub.toronto.edu> koko@uthub.toronto.edu (M. Kokodyniak) writes:
>In article <3816@watdcsu.waterloo.edu>, bmaraldo@watdcsu.waterloo.edu
>> 
>>   I just made a set of 2m long 5mm in diameter mercury filled cables with
>>   copper touch conductors and large lugs.  I really do not have a clue as
>>   to the dynamic characteristics of mercury.
>
>Metals are metals.  Electricity flows in the same way through all metals.
>This includes copper and mercury.

This is not at all true.  Electrons flow in the same direction, yes, but
not in the same manner in all metals.  Apart from the varying
conductivity of different metals, the shape and size of the conductors,
how many of them and their plating, all affect the flow of electrons,
especially when the currents are alternating and the frequency of
alternations (read that: your typical audio signal) varying.

>>                                               If you know anything about
>>   what an audio signal might look like after propagating through such a
>>   cable, I'd like to know, especially if you have data to back your
>>   comments up with.
>
>You have been reading too many audiophile magazines.  As far as audio
>frequencies are concerned, no cables of typical length (i.e. fitting in
>your living room) are going to behave like transmission lines.  Therefore,
>the conductor material, wire configuration and spacing, and insulation
>material are all irrelevant.  So audio signals will look the same on
>copper cables as on mercury ones.

No, YOU haven't read enough audiophile magazines, or other sources of
information that go into detail what actually happens in different
conductors.

The 'sound of wire' discussion is getting tiring.  ANYONE who has done
comparisons in speaker wire on even moderately priced gear knows they
can sound quite different from each other.  The ultimate question is
'which one is right'?  This, by the way, also has some interesting
implications to the 'straight wire with gain' claim made by a number
of high-end audio gear manufacturers, now that it is widely recognized
that a 'straight wire' can have a very distinct sonic signature.

In the most recent Stereophile magazine, Vol 10 No. 6, there are two
very interesting and enlightening articles about the types of things
that cause these conductors to sound different.  I'll paraphrase a few
of the points made.  You'll notice that much of this is very basic
and long-known information about the electron propagation in a
conductor.

Bruce Brisson:

Phase noise is a degrading by-product of a larger cable problem known
as 'delay distortion'.  Instead of passing energy uniformly, non-nuetral
cable actually stores energy, subsequently releasing this energy -- at
the wrong time, and often out-of-phase.  Such cables have a large
'settling time', which means that as a signal passes through these
cables, substantial information is left behind.

This residue then piggy-backs onto the next signal (waveform), producing
audible and out-of-phase sonic additions.  This gremlin is phase noise,
inevitable in any cable not designed to fully pass all frequencies at
exactly the same speed.

...

Cables with delay distortions may at first seem quicker, with more highs
and ambience.  Why?  As discussed, these frequency dependent delays move
energy from one location in a complex waveform to another.  This changes
the resulting waveform or musical tone.  Worse yet, moving energy around
within the tone also results in noise, defocusing and removal of low level
detail.

And from Dick Olsher:

A simplistic view is to regard the skin effect as AC resistance to
current flow that becomes significant and very high frequencies.  This
is a fair macroscopic view of the situation, but it glosses over some
important physical details.  On a microscopic scale, the electromagetic
wave nature of the transmitted signal plays an important role.  With
increasing frequency, a current wave moves into a conductor less and
less, the depth of penetration being only about .5mm at 20khz.  As the
current penetrates the conductor, the relative phase of the current
changes.  With the current density at a maxmimum at the surface and
decreasing inward, the phase is continuously retarded.  Again, it
follows from the skin effect that since the current density is
nonuniform across the conductor, the inductance of the wire decreases
slowly with increasing frequency -- the speed of the propagation of the
highs is faster than that of the lows.

This is a key point.  When modeling signal transfer in audio cables, it
is not only necessary to take into account the variable AC resistance of
the cable, but its variable inductance as well.  The shunt capacitance
of the cable (but not the capacitive reactance) is fixed by the geometry
of the cable and the dielectric properties of the insulation used.
Therefore an electrical model of a single leg of cable would look like a
variable resistor in series with a variable inductance with a shunt
capacitor.  Bruce Brisson of MIT (a cable company) has done this sort of
modeling on a computer.  He has found that a large number of different
diameter wires are necessary to control the impedance of the cable while
minimizing the phase delays due to differential propagation speeds.


----

Of course, there is a lot more to it than just what I've entered here.

There have been some very interesting and objective articles presented
on these and other similar subjects by established and reputable people
in both Sterephile and The Absolute Sound.  In either magazine (and
others) there are also letters-to-the-editor, opinions expressed, and
non-technical columns that occasionally border on bizarre and
unbelievable, which I believe have helped give these magazines a bad
name outside of the 'audiophile' circle.  Nonetheless, there is still
a lot of good information to be had -- the fluff is easily discernable
from objective works researched and presented by extrememly credible
people.

--Bill
        UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!bblue
        ARPA: crash!bblue@nosc.mil
        INET: bblue@crash.CTS.COM

palmer@tybalt.caltech.edu.UUCP (09/12/87)

Just to shed more heat on this subject, it seems to me that most audiophile
discussions of this nature are full of buzzwords and little quantitative
thought, so let me continue this tradition.

Mercury filled cables suffer from signal-induced magnetostrictive non-linear
microphonics.  The resistive impedance has a temporally varying component
with a first derivative w.r.t. time proportional to the second power
of the signal current.  This causes multiplicative mixing of the signal
with a signal with all frequencies doubled, causing objective (as
opposed to subjective) sum and difference frequencies.  At mechanical
resonance, the electrical signal may cause runaway oscillation resulting
in cavitation, yeilding chaotic resistance phenomena.  Near resonance,
high-Q mechanical vibration will cause what laymen call "ringing",
continued oscillation after the driving signal is removed.

Of course, all of this is non-quantitative, and if you work out the numbers,
you will find that these effects would be indetectable for ordinary
current densities and wires.  Nevertheless, I hope that this article
has fanned the flames and opened up new vistas for argument.  Please
direct follow-ups to rec.audio, as I do not read that newsgroup.

From the Cyberpunk Audiophile:
		David Palmer
		palmer@tybalt.caltech.edu
		...rutgers!cit-vax!tybalt.caltech.edu!palmer
	The opinions expressed are those of an 8000 year old Atlantuan
	priestess named Mrla, and not necessarily those of her channel.

gwyn@brl-smoke.UUCP (09/13/87)

In article <3939@cit-vax.Caltech.Edu> palmer@tybalt.caltech.edu.UUCP (David Palmer) writes:
>In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>>  I just made a set of 2m long 5mm in diameter mercury filled cables with
>>  copper touch conductors and large lugs.

I missed the original posting, but please note that mercury is rather
hazardous.  I wouldn't advise people to use it like this, especially
since if it's really for loudspeaker connection it's pretty damn silly.

heppell@cory.Berkeley.EDU.UUCP (09/13/87)

In article <14647@topaz.rutgers.edu> ron@topaz.rutgers.edu (Ron Natalie) writes:
>                               Theoretically, if you had the same resistance,
>dialectric, and relative conductor spacings (and shape) you'd get the same
>performance regarless of what the conductor was made of.

Actually, transmission line performance can vary greatly with conductor
resistance.  At low frequencies, (low is relative to the transmission
line) most of the conduction is bulk instead of surface, but concuctor
resistance still matters.  The resistance of the conductor affects
such things as signal degradation and propagation velocity, which will
in turn affect dispersion.  Admittedly, between DC and 20 kHz, there is
little difference, but some audiophiles will claim to be able to
hear it.  If there is interest, or I have time, I'll work through
the equations and post results.


--------------------------------------------------------------------------------
    Kevin G. Heppell                    USNail: 784 Santa Barbara Rd.
    USENET: ucbvax!cory!heppell                 Berkeley, CA  94707-2046
    arpa:   heppell@cory.Berkeley.EDU           (415) 528-6396

jef@unisoft.uucp (Jef Poskanzer) (09/14/87)

In the referenced article, Space Commander Brett Maraldo wrote:
>I can hear differences between audio cables.  I can not report and
>differences under controlled double-blind tests because I have never
>taken part in one.

Whenever I come across one of these "Emperor's New Ears" types I always
ask him about double-blind tests.  It's refreshing for once to find one
who freely admits his lack of interest in the scientific method.
---
Jef

    Jef Poskanzer  unisoft!jef@ucbvax.Berkeley.Edu  ...ucbvax!unisoft!jef
                   "No cash down! Up to 60 minutes to pay!"

                     ...and now, a word from our sponsor:
    "The opinions expressed are those of the author and do not necessarily
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max@eros.uucp (Max Hauser) (09/14/87)

In article <1700@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:

> In article <578@uthub.toronto.edu> koko@uthub.toronto.edu (M. Kokodyniak) writes:
> >In article <3816@watdcsu.waterloo.edu>, bmaraldo@watdcsu.waterloo.edu
> >> 
> >>   I just made a set of 2m long 5mm in diameter mercury filled cables with
> >>   copper touch conductors and large lugs.  I really do not have a clue as
> >>   to the dynamic characteristics of mercury.
> >
> >Metals are metals.  Electricity flows in the same way through all metals.
> >This includes copper and mercury.
> 
> This is not at all true.

Semantics. The important difference is bulk resistivity. This
determines resistance, and skin-effect depth, and the relative values
of inductance and resistance, and (if you allow for corrosion effects
at the surface) indeed all of the properties cited recently on this
newsgroup. The differences among metals are essentially quantitative,
which I think is what koko was getting at.

> The 'sound of wire' discussion is getting tiring.  ANYONE who has done
> comparisons in speaker wire on even moderately priced gear knows they
> can sound quite different from each other.  

Of course. Competent engineers would have told you this thirty years
ago, if asked. Although the sonic effects may indeed be subtle, the
physical causes are familiar to the point of boredom to persons
trained in E & M (as indeed bblue mentions, next pph).

> In the most recent Stereophile magazine, Vol 10 No. 6, there are two
> very interesting and enlightening articles about the types of things
> that cause these conductors to sound different.  I'll paraphrase a few
> of the points made.  You'll notice that much of this is very basic
> and long-known information about the electron propagation in a
> conductor.
> 
> "Phase noise is a degrading by-product of a larger cable problem known
> as 'delay distortion'.  Instead of passing energy uniformly, non-nuetral
> cable actually stores energy, subsequently releasing this energy -- at
> the wrong time, and often out-of-phase.  [Comment: clumsy explanation;
> as stated, applies to any cable, not just those with delay distortion
> -- MH] ... This residue then piggy-backs onto the next signal 
> (waveform), producing audible and out-of-phase sonic additions.  
> This gremlin is phase noise, inevitable in any cable not designed to 
> fully pass all frequencies at exactly the same speed."

Known concisely to the technical world as "dispersion", and mislabeled
if called "noise" because it is a repeating, deterministic effect.

> And from Dick Olsher:
> 
> "[Mention of skin effect causing freq-dependent resistance and
> inductance in wires] ...  With increasing frequency, a current wave
> moves into a conductor less and less, the depth of penetration being
> only about .5mm at 20khz ...  -- the speed of the propagation of the
> highs [becomes] faster than that of the lows."
> 
> This is a key point.  When modeling signal transfer in audio cables, it
> is not only necessary to take into account the variable AC resistance of
> the cable, but its variable inductance as well...
> 
> --Bill

All of which, of course, constitutes eloquent argument against mercury 
cables, with their much-higher-than-copper resistivity and consequent 
exaggerated impedance effects, as was obvious at the outset to the
technical people on this group (who are now coming in for the usual
knee-jerk criticisms). Since skin depth varies as the square root of
bulk resistivity [1], but resistance is proportional to resistivity
divided by skin depth, the net resistance of the wire increases as the
square root of resistivity when skin-depth effects are considered.
Also, for large wires and audio frequencies, AC inductance also
rises as the square root of resistivity [2]. In other words, higher-
resistivity materials like mercury are bad in every respect, both
simple and subtle effects.

Let us not deceive ourselves: wires have audible differences, but at
the same time one can still go to the hardware store, buy some good
heavy stranded wire, maybe connect several in parallel for good
measure, and come up with cables that will meet the most rigorous
analysis (mine, Olsher's, or anyone's) and sound beautiful, for a few
bucks, without resorting to precious metals, single crystals, or
mercury (this all begins to seem even alchemical at times).
There is no need to contribute *hundreds* of dollars to flaky 
fad-mongering pseudotechnical garage manufacturers who turn out
products named after themselves, as though they were Renaissence
painters, primarily to suit their egos and incidentally to make a
fast buck -- yours.

Respectfully,

Max W. Hauser, UC Berkeley 

   Some numbers: (415) 642-6666; P1-12-20075; 4,435,655
   UUCP: ...{!decvax}!ucbvax!eros!max
   Internet (domain style): max@eros.berkeley.edu

References:

[1] Ramo, Whinnery and van Duzer, _Fields and Waves in Communication
Electronics_, Wiley, 1965, p. 252.

[2] Ramo, Whinnery and van Duzer, pp. 288-297.

ron@topaz.rutgers.edu (Ron Natalie) (09/14/87)

>  Apart from the varying
> conductivity of different metals, the shape and size of the conductors,
> how many of them and their plating, all affect the flow of electrons,
> especially when the currents are alternating and the frequency of
> alternations (read that: your typical audio signal) varying.

I don't think anyone was arguing this point.  The point was the
difference in using Mercury vs. Copper was more likely to be
things like the difference in size and spacing than the nature
of the metal itself.  (By the way, I don't think plating really
helps anything at audio frequencies except for where the wire
is exposed to the air).

> Phase noise is a degrading by-product of a larger cable problem known
> as 'delay distortion'.  Instead of passing energy uniformly, non-nuetral
> cable actually stores energy, subsequently releasing this energy -- at
> the wrong time, and often out-of-phase.  Such cables have a large
> 'settling time', which means that as a signal passes through these
> cables, substantial information is left behind.

This cracks me up everytime I read these smokescreen Stereophile stuff.
If HiFi addicts would just learn a little about electronics they could
discuss things sensibly in the terms that everyone else uses.  This
temporary storage/blockage of energy in a frequency dependent nature
is called REACTANCE.  Not only is this caused by size and spacing of
conductors but is also effected by loops in the cable.  Reactance when
combined with plain old DC resistance (constant with respect to frequency)
is called IMPEDANCE (gee, haven't I heard that term before?)

In addition to the frequency response problems that it generates,
impedance plays a significant factor in the performance of your power
amplifiers.  Despite the nominal impedences given of 4 or 8 ohms, remember
that this is frequency dependent.  The cable/speaker has it's impedance
characturistics and amplifiers have their best performance characturistics.
This is why speakers need to be matched to the amplifiers.


freqencies at the same speed for our purposes.

> As discussed, these frequency dependent delays move
> energy from one location in a complex waveform to another.

Frequency dependent delays are phase changes (probably).  My favorite
was the discussion of using a single DAC in CD players and how this
causes a phase shift between the two channels.  Even worse, a frequency
dependent one.  That's because it was a (non-frequency dependent) DELAY,
which is easily corrected for.

Note that nothing they say is probably really wrong with respect to
what is probably happening to the audible sound, but it would be
MUCH nicer if they would learn the electronics principles when
describing the electronic parts (it is probably not possible to
characturize the audible sensations, which is another issue).

-Ron

bblue@crash.CTS.COM (Bill Blue) (09/14/87)

In article <551@unisoft.UUCP> jef@unisoft.UUCP (Jef Poskanzer) writes:
>In the referenced article, Space Commander Brett Maraldo wrote:
>>I can hear differences between audio cables.  I can not report and
>>differences under controlled double-blind tests because I have never
>>taken part in one.
>
>Whenever I come across one of these "Emperor's New Ears" types I always
>ask him about double-blind tests.  It's refreshing for once to find one
>who freely admits his lack of interest in the scientific method.

The problem with this is that the differences in cables, especially
the speaker cables, is so profound *on high resolution gear* that 
double blind tests are simply not necessary.  It's day and night.
Differences between similarly constructed cables are more subtle, 
however.

--Bill

bblue@crash.CTS.COM (Bill Blue) (09/14/87)

In article <1854@ucbcad.berkeley.edu> max@eros.UUCP (Max Hauser) writes:
>In article <1700@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:
>
[stuff deleted]
>> And from Dick Olsher:
>> 
>> "[Mention of skin effect causing freq-dependent resistance and
>> inductance in wires] ...  With increasing frequency, a current wave
>> moves into a conductor less and less, the depth of penetration being
>> only about .5mm at 20khz ...  -- the speed of the propagation of the
>> highs [becomes] faster than that of the lows."
>> 
>> This is a key point.  When modeling signal transfer in audio cables, it
>> is not only necessary to take into account the variable AC resistance of
>> the cable, but its variable inductance as well...
>
>All of which, of course, constitutes eloquent argument against mercury 
>cables, with their much-higher-than-copper resistivity and consequent 
>exaggerated impedance effects, as was obvious at the outset to the
>technical people on this group (who are now coming in for the usual
>knee-jerk criticisms). Since skin depth varies as the square root of
>bulk resistivity [1], but resistance is proportional to resistivity
>divided by skin depth, the net resistance of the wire increases as the
>square root of resistivity when skin-depth effects are considered.
>Also, for large wires and audio frequencies, AC inductance also
>rises as the square root of resistivity [2]. In other words, higher-
>resistivity materials like mercury are bad in every respect, both
>simple and subtle effects.
>
>Let us not deceive ourselves: wires have audible differences, but at
>the same time one can still go to the hardware store, buy some good
>heavy stranded wire, maybe connect several in parallel for good
>measure, and come up with cables that will meet the most rigorous
>analysis (mine, Olsher's, or anyone's) and sound beautiful, for a few
>bucks, without resorting to precious metals, single crystals, or
>mercury (this all begins to seem even alchemical at times).
>There is no need to contribute *hundreds* of dollars to flaky 
>fad-mongering pseudotechnical garage manufacturers who turn out
>products named after themselves, as though they were Renaissence
>painters, primarily to suit their egos and incidentally to make a
>fast buck -- yours.

While I certainly agree that there are cable companies out there
producing stuff that is far worse than what could be realized from
any reasonably thick multi-strand copper electrical wire (10-12 guage),
I think it's reaching a little too far to say that such cables will 
meet the most rigorous analysis.  Maybe yours, but certainly not
mine, Dick Olshers and a lot of other audiophiles.

In my view, the big culprit that kills the 'hardware store' variety
cables is the varying time of arrival of different frequencies at the
other end of the cable due to skin effect propagation and other factors.
This simply can not be made up for, or controlled by simply paralleling
average cables together.  While they'll have a low DC resistance, and
will allow good control (damping) of the speakers (assuming the amp has
good control in the first place), they will also have a very confused
representation of inner detail.  They most certainly will not pass the
test on any aware audiophile's ears.

I make these statements from personal experience with all sorts of
cables.  Take *any* heavy, stranded, copper cable -- anything from 12/2
or 10/2 electrical cable to the 12 guage (standard) Monster cable
(reasonably cheap at ~$.50/foot) and you'll get a similar sound.  The
number of strands and thickness of each will provide subtle differences,
but all in all they're about the same.  You don't really get into high
definition (the ability to preserve inner detail to the limit of what is
there in the first place) until you get to cables that try to maintain
equal time propagation of various frequency bands through that cable.

But you have to take all this in degrees.  There are many many people,
including quite a few self-proclaimed audiophiles, who have simply never
heard these differences.  It could be for any number of reasons, to
over-regarded equipment to not believing that wire could make any
difference so they never have tried it.  So naturally, if such a person
did replace their cable with multi-strand heavy gauge copper cable from
the 'hardware store' it would probably be an eye-opening experience for
them and theyll begin singing the praises of this discovery -- not yet
realizing that there is still a whole other world of further
improvements they are not yet aware of.  And of course, the better your
equipment (not always measured in dollar value) and the keener your
awareness, the important such differences become.

--Bill

bmaraldo@watdcsu.UUCP (09/14/87)

In article <551@unisoft.UUCP> jef@unisoft.UUCP (Jef Poskanzer) writes:
> In the referenced article, I wrote:
> >I can hear differences between audio cables.  I can not report any
> >differences under controlled double-blind tests because I have never
> >taken part in one.
> 
> Whenever I come across one of these "Emperor's New Ears" types I always
> ask him about double-blind tests.  It's refreshing for once to find one
> who freely admits his lack of interest in the scientific method.

    I agree that double-blind testing is a method of discovering
    differences, or lack there-of, in two or more different audio
    systems.  This can also be said for any method of system evaluation,
    the question is which method provides the most accurate results.
    Double-blind testing seems to be the most accepted method 
    by those who understand the importance of accurate test results.  But
    is double-blind testing the definitive test method?  This is certainly
    and arguable point, as it is as objective as the golden-ear phenomenon.

    I do not feel that a simple double-blind test can report more accurate
    data than an extended listening test.  For me, a double-blind test must
    be rigorous, extended, and thorough; that is, there must be a large
    number of people involved in the evaluation, and the test procedure
    must be overseen by at least one member of a group of potentially biased
    individules (one audio engineer, physicist, golden ear, and stereo
    salesman).  As each procedure is concluded, the overseeres must
    unanimously agree that the procedure was unbiased before enumerating
    the results.  The listening environment must differ between anechoic and
    very 'alive', with each group listening in the different situations;
    one listening environment does not suffice.  

    Unfortunately, this test senario is rarely implemented, let alone
    documented as it would be very expensive and time consuming.  I have
    yet to read about a double-blind test with and description of test
    procedure and environment.  Most audio magazines report that they have
    conducted a double-blind test but do not embellish on the procedure;
    I can not take these reviews seriously.  What I do take seriously are
    what my ears hear.  If I hear a difference between signal cable, you
    can not argue that I do not hear that difference.  You can, how ever,
    argue that my perception is not accurate due to some bias or other
    influence.  This same argument can be overlayed on a poorly conducted
    double-blind test and most do not meet the requirements of an unbiased
    controlled environment procedure.


				Brett L Maraldo


-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

rees@apollo.uucp (Jim Rees) (09/14/87)

  And from Dick Olsher:

  This is a key point.  When modeling signal transfer in audio cables, it
  is not only necessary to take into account the variable AC resistance of
  the cable, but its variable inductance as well...

I decided to do an experiment.  I connected an audio sig gen to my
ultra-cheap stereo amp, put the output of the amp on the H input of
my scope and through 100 feet of cheap Radio Shack speaker cable,
and put the output of the cable on a 8 ohm dummy load and the V input
of my scope.  This should show me the phase change of the signal
through the cable.

At very high frequencies (100KHz) I could detect some phase shift.
I was using about 100 feet of cable, so the shift should be about
4 degrees at this frequency.  I was unable to determine whether the
shift varied non-linearly with frequency (which seems to be what
the claim is; am I right?)

Olsher also says,

  The shunt capacitance
  of the cable (but not the capacitive reactance) is fixed by the geometry
  of the cable and the dielectric properties of the insulation used.

I was trying to calculate the electrical properties of this particular
speaker cable, and discovered that vinyl apparently has a dielectric
constant that varies over a wide range with frequency.  It has close
to a 10% change over the audible range (which for me is about 20-25K).
This should result in about a 5% change in shunt capacitance.  It seems
to me that this is a greater effect than skin effect, at least at these
frequencies.

No matter what numbers I plug in, I can't get any of these effects to
account for more than a .05 db change in signal level or a .1 db
additional noise due to phase distortion.

Here's an idea for audiophile speaker cable.  Only vacuum has a
dielectric constant completely independent of frequency.  Vacuum
filled speaker cable!  I envision something semi-rigid and metal-
clad, sort of like heliax.

If you worry about these things, I think the practical solution is
to put the amplifier physically close to the speaker.  Then you only
need to get a low level signal, at reasonable impedances, to the
amplifier.  And you don't need a ton of copper to carry those watts
at 8 ohms.  You could use fiber optics to connect the signal source
to the amplifier.

Olsher must have done some experiments.  What were his results?

henry@utzoo.UUCP (Henry Spencer) (09/14/87)

>   As for why I made the cables (every mail message I've been getting on the
>   topic has asked WHY):  It seemed like a neat thing to do.  The cables
>   certainly look great and they actually work well.  I would have thought
>   that this little project would have been looked apon with interest but
>   the opposite is true...

Those of us who understand the properties of mercury are looking upon it
with horror, mostly.  I hope the room where you've got those things is
well-ventilated and that humans (and other living things) don't spend long
periods of time in it.  I also hope you've got some sort of catcher tray
under the cables, so that if they leak (say from mercury corrosion of the
end seals), the mercury won't end up on the floor.  Once mercury gets into
a wood floor, it can be damn near impossible to get it out well enough to
make the room safe again.

(I know chemists often are kind of casual with mercury.  I got perhaps
halfway to being one before I got diverted into computing.  Chemists are
often kind of casual with far too many things; this may be one reason why
they have a shorter average life expectancy than physicists.)
-- 
"There's a lot more to do in space   |  Henry Spencer @ U of Toronto Zoology
than sending people to Mars." --Bova | {allegra,ihnp4,decvax,utai}!utzoo!henry

phd@speech1.cs.cmu.edu (Paul Dietz) (09/15/87)

In article <1854@ucbcad.berkeley.edu> max@eros.UUCP (Max Hauser) writes:
Lot's of good stuff about Speaker wires...

Here's my 2 cents worth:

For those of you who claim to hear a difference between reasonable cables,
here's a possible explanation: it's not the wire per say; it's the amp.

	Yes, some amplifiers are rather finiky about the load they see.
Different cables will significantly alter the impedance, especially at
low frequencies. (i.e. a cable's resistance is often a reasonable
fraction of 4/8 ohms) And it is quite concievable that this shift
in the 'operating point' of your amp can change the frequency response.
The important question is: Do you really care? 
	From the speakers I've measured,
the input impedance varies quite a bit, even in a
matched pair. Much more so than a piece of heavy zip cord will
change it. So, if the speakers are much more inconsistent than
the wire, why worry about the wire. Another way to look at this
is from an acoustical point of view. Unless you're listening to
your speakers in a perfectly symmetrical environment, the differences
will probably be mostly due to the room, and your position in it.
(Go read Beranek's book "Acoustics" reprinted by the Acoustical
Society, and you'll see how bad this problem really is...")
	The point? With an A/B test, you might actually be able
to distinguish between cables, though I know I can't. But you
certainly will be able to distinguish between different speaker
placements, and quite possibly between different speakers, even
when placed in the same position. (By different speakers, I mean
in a matched set.) If you're really picky, go buy a good
equalizer. It will probably help. But don't waste your time/money
on cables more exotic than zip cord. 
	I don't read rec.audio either, so please feel free to
post there...


-- 
Paul H. Dietz                                        ____          ____
Dept. of Electrical and Computer Engineering        / oo \        <_<\\\
Carnegie Mellon University                        /|  \/  |\        \\ \\
--------------------------------------------     | | (  ) | |       | ||\\
"If God had meant for penguins to fly,             -->--<--        / / |\\\  /
he would have given them wings."            _________^__^_________/ / / \\\\-

bmaraldo@watdcsu.UUCP (09/15/87)

In article <8576@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes:
> Those of us who understand the properties of mercury are looking upon it
> with horror, mostly.  I hope the room where you've got those things is
...

   The ends are sealed with a large plug of hot glue which melts the inside
   surface of the plastic and forms itself into the wall of the tube.  The
   plugs have been tested and comply with my safty standards which are
   high.

				Brett L Maraldo



-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

max@eros.uucp (Max Hauser) (09/15/87)

In article <1709@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:
> In my view, the big culprit that kills the 'hardware store' variety
> cables is the varying time of arrival of different frequencies at the
> other end of the cable due to skin effect propagation and other factors.

OK, I will concede that hardware-store cables of the casual variety
may suffer from this problem. When I asserted that one could build
hardware-store cables meeting arbitrary specifications, I specifically
meant reactance and dispersion as well as resistance, based on some
knowledge of these effects and on the properties of copper wire.
However I have not tried it, while bblue has, and I value that 
experience. Nevertheless, I am convinced that high-quality cables,
even with these subtle problems resolved, need not be expensive.

Understand that in the following I am now speaking of VERY
high-quality speaker cables, since even casual hardware-store
cable, heavily stranded and paralleled, and kept as short as
possible, will palpably outperform even many "audio" cables.

Now, to hear it described recently on the net, one would think 
that Dick Olsher and co. had discovered dispersive propagation and
its relation to conductor effects.  In reality these are old, prosaic
problems, familiar to thousands of people in this country (some
of whom are even on the net). In fact, since these problems first
surfaced in long-disance wired telegraphy, they even predate 
electronics (a term, incidentally, coined by McGraw-Hill to title
a trade magazine -- the magazine came before the field). 

Varying time delay for signals of different frequencies (also 
called dispersion, or phase nonlinearity) comes up in many contexts
(phase nonlinearity in analog filters for digital audio was 
discussed to death on rec.audio), as do such conductor nonidealities
as skin effect and distributed inductance. However, these problems
also admit creative solutions, which can be as simple as tolerating
the cable effects and adding a small compensating network in the 
preamp, properly done, of course. That the problems are unfamiliar
to consumers does not mean that their solution requires genius,
or an approach obviously related to the source of the problem, or
even (the seemingly inevitable) hundreds of dollars per unit.

Moreover, if you are going to seriously regard [good split infin.]
"skin effect propagation and other factors" as physical, rather
than just rhetorical, effects, and then someone comes up with
a nice cheap solution that measurably fixes these physical effects,
then you are bound to (as Sam Spade said to Joel Cairo) "take it and
like it," or else stop claiming that you know the *physical basis*
for cables' sonic imperfections. For many people this is a tall order.

Max Hauser

   UUCP: ...{!decvax}!ucbvax!eros!max
   Internet (domain style): max@eros.berkeley.edu
   Internet (old style): max%eros@berkeley

jeffw@midas.TEK.COM (Jeff Winslow) (09/15/87)

In article <1709@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:

>In my view, the big culprit that kills the 'hardware store' variety
>cables is the varying time of arrival of different frequencies at the
>other end of the cable due to skin effect propagation and other factors.

What is "skin effect propagation", explained in physical terms used in
their intended fashion?

Reading strangeness such as this makes me suspect the author doesn't really
know what he's talking about. But I'm willing to be instructed.

		Jeff Winslow
		"A silver platter! Isn't she charming?" - Herod, Salome

mike@ivory.SanDiego.NCR.COM (Michael Lodman) (09/15/87)

In article <8576@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes:
>Those of us who understand the properties of mercury are looking upon it
>with horror, mostly.  I hope the room where you've got those things is
>well-ventilated and that humans (and other living things) don't spend long
>periods of time in it.  I also hope you've got some sort of catcher tray
>under the cables, so that if they leak (say from mercury corrosion of the
>end seals), the mercury won't end up on the floor.  Once mercury gets into
>a wood floor, it can be damn near impossible to get it out well enough to
>make the room safe again.
 
As an example of a horror story, some people I know had a small bottle
of mercury in their home , for one reason or another. A small fire broke out
and the mercury bottle was close enough that part of it vaporized.
Following the fire, the house was condemned as being unfit for human
habitation, even though the damage was easily repaired, just because
the bottle of mercury was found by the fire department. The house was 
completely demolished. I'm not sure what the insurance company thought
about it.

Also, a book I read once had someone place a single drop of mercury in
the shoe of someone that they wanted to get rid of. In three months
the person was dead, and the crime was not solved.

My advice to you is to not use the mercury filled cables no matter
how good the sound quality is and not to permit them to remain in
your home. 

-- 
Michael Lodman  (619) 485-3335
Advanced Development NCR Corporation E&M San Diego
mike.lodman@ivory.SanDiego.NCR.COM 
{sdcsvax,cbatt,dcdwest,nosc.ARPA,ihnp4}!ncr-sd!ivory!lodman

When you die, if you've been very, very good, you'll go to ... Montana.

dmt@mtunb.ATT.COM (Dave Tutelman) (09/16/87)

In article <3837@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>    Double-blind testing seems to be the most accepted method 
>    by those who understand the importance of accurate test results.  But
>    is double-blind testing the definitive test method?  This is certainly
>    and arguable point, as it is as objective as the golden-ear phenomenon.
	If I understand what the "golden-ear phenomeneon" is, it isn't at
	all objective.  It's totally subjective.  Maybe you could explain
	what you mean, and disabuse me of this opinion.
>
>    For me, a double-blind test must
>    be rigorous, extended, and thorough; that is, there must be a large
>    number of people involved in the evaluation, and the test procedure
>    must be overseen by at least one member of a group of potentially biased
>    individules (one audio engineer, physicist, golden ear, and stereo
>    salesman).  As each procedure is concluded, the overseeres must
>    unanimously agree that the procedure was unbiased before enumerating
>    the results.  The listening environment must differ between anechoic and
>    very 'alive', with each group listening in the different situations;
>    one listening environment does not suffice.  
>
>    ....  This same argument can be overlayed on a poorly conducted
>    double-blind test and most do not meet the requirements of an unbiased
>    controlled environment procedure.
>
	Perhaps we ought to review the DEFINITION of a double-blind test,
	as the description above carries a lot of extra baggage (useful in
	testing audio equipment, but having nothing to do with double-blind)
	and misses the fact that double-blind methodology is INHERENTLY
	unbiased (no "agreement" among the overseers is needed if
	the methodology is double-blind).

In a double-blind experiment, TWO parties are "blind":  (1) the subjects
(you knew that, of course), and (2) the "overseer" of the experiment.
The pattern of the experiment is created by a random number generator,
and administered by a tester that doesn't know which experiment is currently
going.  In a medical experiment, this means that both the patient and
the doctor are ignorant as to whether the patient is in the experimental
or control group.  In an audio experiment, this means that both the
"golden ears" and the person doing the switching are ignorant about
which equipment is being played.  There ARE techniques for assuring this.
If they are used, the test WILL be unbiased.  You can criticize other
aspects of the test (room too "live", statistically insignificant
number of subjects, tone-deaf subjects :-), but it is innocent
of bias.

+---------------------------------------------------------------+
|    Dave Tutelman						|
|    Physical - AT&T  -  Lincroft, NJ				|
|    Logical -  ...ihnp4!mtuxo!mtunb!dmt			|
|    Audible -  (201) 576 2442					|
+---------------------------------------------------------------+

russ@crlt.UUCP (Russ Cage) (09/16/87)

In article <1709@crash.CTS.COM>, bblue@crash.CTS.COM (Bill Blue) writes:
>In my view, the big culprit that kills the 'hardware store' variety
>cables is the varying time of arrival of different frequencies at the
>other end of the cable due to skin effect propagation and other factors.
>This simply can not be made up for, or controlled by simply paralleling
>average cables together.  While they'll have a low DC resistance, and
>will allow good control (damping) of the speakers (assuming the amp has
>good control in the first place), they will also have a very confused
>representation of inner detail.  They most certainly will not pass the
>test on any aware audiophile's ears.

Okay, to put the "differences in arrival time" argument to rest,
*permanently*:

Let us assume that we have a cable which is *extremely* dispersive.
At 20 Hz, signals propogate at .6c (velocity factor of .6); on the
other hand, at 20 KHz, they propagate at .4c.  (Typical variations
in a *real* cable over much larger ranges might be a few percent.)
Assume for a moment that our cable has:

1.)	Insignificant non-linear effects (not too unlikely), and
2.)	A ten-meter length.

What happens to a mix of signals from 20 Hz to 20 KHz, going from
one end to the other?

The 20 Hz signals move off at .6 of the speed of light.  They cover
the ten meters in 5.56e-8 seconds, or 56 nanoseconds.  The 20 KHz
signals arrive more slowly; they take 8.33e-8 seconds, or 83 nanoseconds,
to arrive.  Thus, they get to the speaker 28 nanoseconds later.

This 28 nanosecond delay is about one two-thousandth of a cycle
time at 20 KHz, or about two-tenths of a degree of phase delay
at the *maximum* frequency; it will be much less at the frequencies
where phase perception is important.  Is there *anyone* who can hear
such a phase delay?  I doubt it.

Note that dispersion in any *real* cable is going to be less by
orders of magnitude, and you'll see how ridiculous this discussion
about cables is.  Dispersion is simply not a factor; resistance,
on the other hand, affects the damping of the speaker by the
amplifier, and thus has a *large* effect on sound quality.  Skin
effect can be dealt with by using flat conductors or Litz wire,
or (again) *several parallel strands*.

Followups to rec.audio.technobabbling; keep this out of sci.*.
-- 
  The above are the official opinions and figures of Robust Software, Inc.
HASA, "A" division.                      Go ahead, flame.  I bought Dow stock!
Russ Cage, Robust Software Inc.		    ihnp4!itivax![m-net!rsi,crlt!russ]

grelling@mmm.UUCP (09/16/87)

AAARGH!  I can't stand it anymore!!!  I don't care about Mercury filled 
speaker wire!   In fact, I never cared about mercury filled speaker wire!
Please take sci.electronics and sci.physics out of the
Newsgroups: header.  Continue this rediculous discussion in rec.audio.
I, and many others, would be forever in your debt!

				-- Kevin

-------------------------------------------------------------------------
| Kevin P. Grelling                            Software  &  Electronics |
|                                              Resource Center   --  3M |
| Disclaimer?  I ain't got no disclaimer...    Minneapolis/St. Paul, MN |
| I don't need no !#%&%#! disclaimer!                                   |
|                                                                       |
| EMail: ...ihnp4!mmm!grelling                    Ph: (612)736-9272     |
-------------------------------------------------------------------------

jj@alice.UUCP (09/16/87)

> = Maraldo on double blind testing...
The numbers in parenthises are mine, and refer to comments below.
>     I do not feel that a simple double-blind test can report more accurate
>     data than an extended listening test. (1) For me, a double-blind test must
>     be rigorous, extended, and thorough; that is, there must be a large
>     number of people involved in the evaluation(2), and the test procedure
>     must be overseen by at least one member of a group of potentially biased
>     individules(3) (one audio engineer(4), physicist(5), golden ea(6), and stereo
>     salesman(7)).  As each procedure is concluded, the overseeres must
>     unanimously agree that the procedure was unbiased before enumerating
>     the resultsa(8).  The listening environment must differ between anechoic and
>     very 'alive'(9), with each group listening in the different situations;
>     one listening environment does not suffice. 


(1) You say "feel", but you do not address the many published references
that assert you are completely incorrect.  Certainly any test must be done
in an unbiased manner, and a careful and thorough description of the
test conditions should be in the test report, to show beyond any doubt
what the test did, and what the test did not, control.

(2) There are simple statistical tests for "how many is enough", and good
tests report on their statistical significance as a matter of course.

(3) It's not clear what having biased individuals "oversee" a test amounts
to.  If it's censorship of something that, for example, audio salesmen
don't want known (the relationship between small loudness differences
and 'quality', for example), then you'll get your way, I'm sure.
You say "individuals", you then proceed to name:

(4) audio engineer -  Perhaps reasonable, certainly the equipment must
be working correctly, and all equipment in a subjective test
should be periodically verified.  Perhaps the engineer will also
have some knowledge of what the test is about, if so, the bias
must be deliberately EXcluded.

(5) physicist -  I don't know why you say this.  Perhaps you mean
acoustician, psycho-acoustician, physiological acoustician, or somethiung
like that, but what a particle physicist, for example, would do is
beyond me.  If you mean something more specialized, say it, after all,
you appear to be attempting a concise requirements document.

(6) Golden ear - Say what?  Define "golden ear".  If you mean people
who appear to have very good hearing, and can detect differences that
other people usually can't, I'd rather have them IN the test.  I'd prefer
to have one or two try out the equipment beforehand, to ensure correct
operation, but what's the POINT of having a non-expert verify the 
experimental design and operation.

(7) Stereo salesman.  -  This is silly, ridiculous, and downright
offensive.  While there ARE good stereo salesmen, most stereo salesmen
(or women, or critters) are simply out to make a buck.  Those in "high-end"
stores are very prone to flights of superstition, and most insist that
"double blind tests are stupid", hence one such individual would never
"pass" a double-blind test.  Ever.  Perhaps that's your hidden agenda?

(not a number, because you left out the important person) - An expert
in  subjective testing, usually a psychologist or acoustician with
extensive experience in subjective testing, test design, test administration,
and what-have-you.  THIS is it MOST important thing to have oversee a test,
and if possible, run it.  The fact that you don't even mention it speaks
very poorly of your attempted defination of a proper  subjective test.

(8) Why?  You should have your "oversight" folks ensure that the test
is working correctly, and indeed tests what it attempts to test,
as much as that can be shown.  That much is commonly done in some
circles, I fear that audio testing often isn't one of them.

(9) Now, then, this is just plain, ordinary stupid, unless what you're
testing is the effects of listening environments on whatever it is
that your subjects are supposed to detect.  If you're NOT trying
to test that effect, then one, perhaps, might want to try to
isolate the subject from these confusing and interfering influences,
and try to lower the noise-level of the testing process.

If you're trying to isolate the differences in (for example)
low-level cables, surely you don't want to mask the effects
with the room-induced frequency shaping, auditory masking
due to reflections and diffraction,  energy-storage effects of
the room that provide very-long-term self-interaction of
a signal, and so on, do you?  All those effects are shown,
in careful tests, to reduce the sensitivity of a subject
to make a RELIABLE decision.

I'm NOT going to post the whole damned bibliography for this
AGAIN, damnit.

-- 
TEDDY BEARS HAVE *GREEN* EYES!
"...Farewell even to our Scottish name, so ..."
(ihnp4;allegra;research)!alice!jj
Copyright JJ 1987.  All rights to mail reserved, USENET redistribution otherwise granted to those who allow free redistritution.

mitch@stride1.UUCP (Thomas P. Mitchell) (09/16/87)

In article <2166@sigi.Colorado.EDU> heuring@boulder.Colorado.EDU (Vincent Heuring) writes:
>In article <3816@watdcsu.waterloo.edu> bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>>
>>  I just made a set of 2m long 5mm in diameter mercury filled cables with
>
>I can see the review by Anthony Cordesman now:
>
>	"This wire lends a liquid transparency to strings. The fluid quality
>	of horns has to be heard to be believed.  There is a silvery
>	quality to the brass, with no sign of the hard-edged, coppery
>	sound normally associated with speaker cable...

And later as Anthony is slowly poisoned by the Hg vapor from an
undetected leak the review flows into a dialogue reminiscent of
Edgar Allan Poe.

Perhaps there are those on the net who can tell us the name of
the famous author who had his study painted a wonderful Cinnabar
red in his last years.  Cinnabar is a natural mineral, HgS.  

Mercury is bad stuff!!!!  If you wish to live long and prosper.
Do not play with that stuff!!  Bletch gag :-( borf gorp etc.
Thomas P. Mitchell (mitch@stride1.Stride.COM)
Phone:	(702) 322-6868 TWX:	910-395-6073
MicroSage Computer Systems Inc. a Division of Stride Micro.
Opinions expressed are probably mine. 

bde@ihlpl.ATT.COM (Bryan Ewbank) (09/16/87)

RSTLNErstlne

In several articles, people have written:
> . . . the big culprit that kills the 'hardware store' variety
> cables is the varying time of arrival of different frequencies at the
> other end of the cable due to skin effect propagation and other factors.

;-) ON
Skin effect propagation, huh?  Is that why netnews articles get jumbled
so that all of the common letters appear at the front of a posting?  Maybe
that explains all of those spurious typos people complain about.
;-) OFF
-- 
-- Bryan Ewbank, <ih-tba>!bdewbank, IH 1C-407, x5146
   "do the right thing right the first time"

sukenick@ccnysci.UUCP (09/17/87)

Experimenting with mercury in your home <for a `better sound' in speaker wire,
yet> is like using lead to sweeten your wine and  using powered arsenic to
clean your walls.  It wouldn't kill you right away, but its effects are
cumulative, possibly damaging, and there are better ways to sweeten drinks
or clean walls.

>As an example of a horror story, some people I know had a small bottle
>[of mercury, there was a fire, the house was condemned dur to the mercury]

Thats probably all it is, a horror story ... unless:
Everyone, quick! throw out your thermometers and barometers or else
your house will be condemned too if hit by fire!  :-)

>Also, a book I read once had someone place a single drop of mercury in
>the shoe of someone that they wanted to get rid of. In three months
>the person was dead, and the crime was not solved.

So, the world population of dentists and electrochemists should
have died (and not just gone mad :-) many years ago...

>My advice to you is to not use the mercury filled cables no matter
>how good the sound quality is and not to permit them to remain in
>your home. 

I agree.  Mercury IS a pretty bad substance to handle, and difficult or
impossible to get rid of completely if spilled (or the vapors
when exposed to air).  As with many heavy metals, the body does not
have a good mechanism for ridding itself of it.  Many of its organic
compounds are toxic or cancerous.

But someone is already using it so they should know this:
  The standard procedure for handling
a spill (or if it is exposed to the air) is after getting up the visible
pieces (shovel it; and  use a shiny copper wire to pick it up (stranded is best)
- the mercury  will form an amalgam on the wire), spread powered sulfur on and
beyond the area that the spill took place (those little drops can really travel
- once spilled, its everywhere!)  The fumes from the sulfur will also help take
care of some of the mercury vapors.  Clean up the powder and repeat a few times.
remember - this will get much of the spill, but not necessarily all.
------

What a pretty sight!
While the chemists are turning colors;
the physicists are glowing in the dark!

al@gtx.UUCP (09/17/87)

 bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes

-> 
->     I do not feel that a simple double-blind test can report more accurate
->     data than an extended listening test.  For me, a double-blind test must
->     be rigorous, extended, and thorough; that is, there must be a large
->     number of people involved in the evaluation, and the test procedure
->       ...               If I hear a difference between signal cable, you
->     can not argue that I do not hear that difference....

When you say you "hear a difference between signal cable", I certainly
hope you mean that you have a friend connect the cables, without
telling you which ones you are listening to.  You don't have to do a
production number with a cast of thousands, just use common sense. This
is what you meant by a "listening test", isn't it?  This is effectively
"double-blind" as long as your friend doesn't talk to you during the
test.

Look first for the beam in the eye of the experimental procedure,
before looking for the mote in the eye of the audio signal. (Note:
this metaphor is probably a result of the fact that we used to play
with Mercury, coat dimes with it, roll it around on our tables, etc. in
high school Chemistry lab.)

    ----------------------------------------------------------------------
   | Alan Filipski, GTX Corp, 2501 W. Dunlap, Phoenix, Arizona 85021, USA |
   | {ihnp4,cbosgd,decvax,hplabs,seismo}!sun!sunburn!gtx!al (602)870-1696 |
    ----------------------------------------------------------------------

"And laughter unquenchable arose among the blessed gods" -- Homer

carl@aoa.UUCP (09/17/87)

In article <750@mas1.UUCP> ejm@mas1.UUCP (Eric Mattern) writes:
>>
>>				I'm an audiophile and I hate CD's and I'm
>>				damn proud of it!  So there!  NAA!
>>
>>				Brett L Maraldo
>
>	      I'm with you !!!
>
OK, my permittable ( :==>) one flame per month:

I'm an "audiophile" and a high quality amateur musician and I say:

FOOOOOEEEEY on you snobby slobs!!!!!!!!   CDs sound as good as the
master recording allows and dont wear out. So, for those of us who
refuse to spend more than $1k for speakers or more than $250 for 
cartridges (phono), CDs are gobs better than LPs. 

SO THERE.

AS THIS is a flame, no responses are permitted.

-- 

Alix's Dad ( Carl Witthoft @ Adaptive Optics Associates)
{ima,harvard}!bbn!aoa!carl
{wjh12,mit-vax}!biomed!aoa!carl
54 CambridgePark Drive, Cambridge,MA 02140 617-864-0201
" If you're not afraid you're going to die on your windsurfer,
the wind isn't high enough to have a good time."

heuring@boulder.Colorado.EDU (Vincent Heuring) (09/18/87)

In article <750@mas1.UUCP> ejm@mas1.UUCP (Eric Mattern) writes:
>>				I'm an audiophile and I hate CD's and I'm
>>				damn proud of it!  So there!  NAA!
>>				Brett L Maraldo
>	      I'm with you !!!
>	      rick
>
Right! F'n. A, man. Enough of these bullshit CD's. Everybody knows
they leave holes in the music. Alvin Gold said so right there in
Stereophile. Caused by the digital sampling.  Any fool can hear
the difference.  Leave us to our 33-1/3 rpm perfection. Why, we'll take
the sonic print-through, pops, clicks, poor s/n ratios, and bad dynamic
range any time. Hell of a lot better than those little wimpo silver disks
with the rainbow on 'em.  I want my vinyl, my vacuum tubes, my diamond
stylus, and my 450 pound turntable. Fuck rationality.

Goddamn technocrat hippie freaks.

Get a Horse!

bmaraldo@watdcsu.UUCP (09/18/87)

In article <1067@mtunb.ATT.COM> dmt@mtunb.UUCP (Dave Tutelman) writes:
> 	If I understand what the "golden-ear phenomeneon" is, it isn't at
> 	all objective.  It's totally subjective.  Maybe you could explain
> 	what you mean, and disabuse me of this opinion.


   Your right, I meant subjective.  Sorry.

					BLM


-- 
               --------     Unit 36 Research     ---------
	                "Alien Technology Today"
               -------------------------------------------
	                    bmaraldo@watdcsu

drw@culdev1.UUCP (Dale Worley) (09/18/87)

koko@uthub.toronto.edu (M. Kokodyniak) writes:
> If they were available on the market, I wouldn't buy mercury cables because
> they are not worth the expense and because any mercury leakage would be
> hazardous, and would require special equipment for cleanup.

My high-school chem teacher told me one trick for dealing with spilled
mercury: Scatter sulfur dust.  Apparently, sulfur will react with the
mercury vapor from the tiny drops of mercury that get caught in the
cracks, etc.

Dale

drw@culdev1.UUCP (Dale Worley) (09/18/87)

bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>    What you have said here is simply a matter of opinion.  I
>    can hear differences between audio cables.  I can not report and
>    differences under controlled double-blind tests because I have never
>    taken part in one.  I am not attempting to convince you that I can hear
>    a difference, but what I hear is good enough for me.

I once worked in the engineering section of Bose Corp. (as a computer
programmer).  Some of the engineers there once discussed the fact that
certain audio effects that everybody agreed were real (not placing
speakers directly against the wall makes them sound better) could not
be reproduced in blindfold experiments.

Conclusion:  "What one hears" is only a very poor reflection of
"what's really out there".  The enterprise of science has spent an
enormous amount of effort in "learning how to measure", so that the
myriad factors that color our perceptions can be avoided.  The ability
of our expectations and culture to determine what we see is enormous.

After all, how could someone believe something as rediculous as the
religious beliefs that *other people* believe?  But aren't we all very
fixed in our religious beliefs, and don't they come from observation
of just about the same data?

Dale

drw@culdev1.UUCP (Dale Worley) (09/18/87)

larry@kitty.UUCP (Larry Lippman) writes:
> 	Actually, you have touched upon a grain of truth.  Mercury-filled
> tubing - expecially of the silicone rubber variety - makes a simple, but
> effective position transducer.  As the cable is stretched, both the length
> of the mercury column increases and its diameter decreases in the affected
> area; this results in greater electrical resistance as the tubing is
> stretched.

Though, since the resistance of the cables is around 0.1 ohm, and the
speakers are around 4 ohms (they used to be, has this changed?  and is
this DC or AC resistance?), the bulk of the voltage drop is across the
speakers.  Or is even such a small effect (if it has an audio period)
audible?

Dale

drw@culdev1.UUCP (Dale Worley) (09/18/87)

Just to shed more heat on the subject, I'm going to challenge what
seems to be a very unlikely statement.  I only read this on
sci.physics and I've removed it from the newsgroups, so I (hopefully)
won't have to read zillions more messages of audiophile nonsense...

bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo) writes:
>   And how about the crystal structure?  THERE ISN'T ONE in mercury!  It is
>   know that linear crystal (lon crytal) configuration wire propagates a
>   signal with more linear accuracy.  In the mercury cables there is now
>   crystal stucture and this is material dependent.

"It is known"?  Has this been confirmed in a laboratory setting?  (I
mean, in a laboratory not owned by a company selling such things or a
magazine accepting ads for such things.)  Or is this another "I can
HEAR the difference" argument?

"It isn't going to sci.physics because there isn't any science in
it..."

Dale

agn@unh.cs.cmu.edu (Andreas Nowatzyk) (09/18/87)

The phenomenon of dispersion in cables has been brought up to explain alleged
differences in speaker cables. Let's see: dispersion is a frequency dependent
change in the cable delay that is observed in a transmission line. The delay
of a transmission line is roughly:

   Tpd = 1.017 * sqrt (0.475 * e + 0.67)        [ns/ft]

where "e" is the relative dielectric constant of the insulator, which in turn
is dependent on the frequency. Let's assume a really bad insulator (you won't
be able to find one like that) that has e(dc)=5 and e(20Khz)=2.5.
So this insulator behaves like PVC at DC and like Teflon at 20Khz. Assuming
30 ft cable legnth, we get: Tpd(DC) = 53 ns,  Tpd(20Khz) = 42 ns.

That cable must sound awfull: the high frequencies arrive 11ns earlier!! :-)
This is a phase error of 0.08 degrees.

Audiophile: Someone who can hear the color of the front panel.

-- 
   --  Andreas Nowatzyk  (DC5ZV)

   Carnegie-Mellon University	     Arpa-net:   agn@unh.cs.cmu.edu
   Computer Science Department         Usenet:   ...!seismo!unh.cs.cmu.edu!agn

pac@munsell.UUCP (Paul Czarnecki) (09/19/87)

In article <1709@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:
>In my view, the big culprit that kills the 'hardware store' variety
>cables is the varying time of arrival of different frequencies at the
>other end of the cable due to skin effect propagation and other factors.

>I make these statements from personal experience with all sorts of
>cables.  Take *any* heavy, stranded, copper cable -- anything from 12/2
>or 10/2 electrical cable to the 12 guage (standard) Monster cable
>(reasonably cheap at ~$.50/foot) and you'll get a similar sound.  The
>number of strands and thickness of each will provide subtle differences,
>but all in all they're about the same.

Why must you use stranded cable?  I realize the mechanical
difficulties in using a solid core cable but are there any electrical
problems?

I used 12 gauge solid core for many years.  It was the cheapest stuff
I could find.  (It was UL listed for underground use also. :-)

Just curious...

					pZ
-- 
			       Paul Czarnecki -- My newsfeed's in Esperanto
	{{harvard,ll-xn}!adelie,{decvax,allegra,talcott}!encore}!munsell!pz

larry@kitty.UUCP (Larry Lippman) (09/19/87)

In article <1538@culdev1.UUCP>, drw@culdev1.UUCP (Dale Worley) writes:
> > 	Actually, you have touched upon a grain of truth.  Mercury-filled
> > tubing - expecially of the silicone rubber variety - makes a simple, but
> > effective position transducer.  As the cable is stretched, both the length
> > of the mercury column increases and its diameter decreases in the affected
> > area; this results in greater electrical resistance as the tubing is
> > stretched.
> 
> Though, since the resistance of the cables is around 0.1 ohm, and the
> speakers are around 4 ohms (they used to be, has this changed?  and is
> this DC or AC resistance?), the bulk of the voltage drop is across the
> speakers.  Or is even such a small effect (if it has an audio period)
> audible?

	Mercury-filled tubing forms a simple one-axis/one-element strain
gage transducer.  Its gage factor (strain sensitivity) is pretty small
due to the comparatively small resistivity of mercury.  Gage factor =
(delta_R/R)/(delta_L/L) where (delta_R/R) = resistance change, and
(delta_L/L) = strain.
	Is the strain gage effect audible?  To normal, objective people:
hell, no!  To "Golden Ears": hell, yes! :-)

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231       {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}   "Have you hugged your cat today?" 

jwl@ernie.Berkeley.EDU (James Wilbur Lewis) (09/21/87)

In article <630@ccnysci.UUCP> sukenick@ccnysci.UUCP (George Sukenick) writes:
-  The standard procedure for handling
-a spill (or if it is exposed to the air) is after getting up the visible
-pieces (shovel it; and  use a shiny copper wire to pick it up (stranded is best)
-- the mercury  will form an amalgam on the wire), spread powered sulfur on and
-beyond the area that the spill took place (those little drops can really travel
-- once spilled, its everywhere!)  The fumes from the sulfur will also help take
-care of some of the mercury vapors.  Clean up the powder and repeat a few 
-times.
-remember - this will get much of the spill, but not necessarily all.

And when you're finished cleaning up and wondering how to dispose of it,
please remember that you're dealing with toxic waste.  Your friendly
neighborhood landfill (and users of any nearby water supplies) would probably 
not appreciate anything tainted with mercury.

-- Jim Lewis
   U.C. Berkeley

mike@ivory.SanDiego.NCR.COM (Michael Lodman) (09/21/87)

In article <630@ccnysci.UUCP> sukenick@ccnysci.UUCP (George Sukenick) writes:
>>As an example of a horror story, some people I know had a small bottle
>>[of mercury, there was a fire, the house was condemned dur to the mercury]
>
>Thats probably all it is, a horror story ... unless:
>Everyone, quick! throw out your thermometers and barometers or else
>your house will be condemned too if hit by fire!  :-)

No, this really did happen. Mercury is sold in plastic bottles, in case
you didn't know, and it tends to melt at a much lower temperature
than the glass they use in thermometers etc. Also, there really isn't 
much mercury in a thermometer, and this was a 2 1/2 pound bottle of
the straight metal.

Please be careful of accusing someone of having an overly vivid
imagination!



-- 
Michael Lodman  (619) 485-3335
Advanced Development NCR Corporation E&M San Diego
mike.lodman@ivory.SanDiego.NCR.COM 
{sdcsvax,cbatt,dcdwest,nosc.ARPA,ihnp4}!ncr-sd!ivory!lodman

When you die, if you've been very, very good, you'll go to ... Montana.

jeffw@midas.TEK.COM (Jeff Winslow) (09/22/87)

I even put a little real physics in...

In article <1741@crash.CTS.COM> bblue@crash.CTS.COM (Bill Blue) writes:
>In article <1222@pinney.munsell.UUCP> pac@pinney.UUCP (Paul Czarnecki) writes:
>>
>>Why must you use stranded cable?  I realize the mechanical
>>difficulties in using a solid core cable but are there any electrical
>>problems?

>I believe the big problem with large gauge solid conductor cable is
>skin effect related.  The diameter is simply too large for reasonable
>handling of high frequencies...

Maybe. But remember that, unless the strands are insulated from each other
(as in Litz wire) the current distribution in a stranded conductor will be
very similar to that in the same sized solid conductor. And even in Litz
wire, proximity effect will tend to push the current to the surface of the
wire to some degree.

I'm not sure what you mean by "too large for reasonable handling of high
frequencies". The larger the wire, the more surface it has to conduct HF
current, and the smaller the impedance at *any* audible frequency as
compared to the speaker impedance. The larger the better, skin effect or
no (assuming you have plenty of room for cables!). 

I'd be curious to know how you routed the cables. Stranded wire, being
more flexible than the same diameter solid wire, would make it easier
to minimize the loop area (hence inductance) in the cable. This seems
more likely the cause of the problem than any magic involving solid
and uninsulated stranded, to me. (Of course, I wasn't there.)

>It always has struck me rather funny when engineer types (not recording
>but electronics) go into long dissertations on how we audiophiles can't
>be hearing differences in so-and-so cables, or capacitors, or resistors,
>or (gasp) power supplies, and spout streams of numbers and other
>specifications that 'prove' such things don't apply to audio
>frequencies.  Years later though, when it becomes generally accepted
>that such things do in fact make audible differences, the same engineers
>not only agree that these things do make a difference, but can spout
>reasons why.

In the meantime, you have forgotten about the things that you *thought*
made a difference at one time, and have turned out, in fact, to make no
difference, for the reasons given by the electronics engineers. Everybody
remembers the exceptions - the times when the experts were wrong. Who
remembers when the experts were right? Shucks, that's not news. Wonder
why?

			Jeff Winslow
			"Hit him again!!!!" - Elektra/Strauss

drw@culdev1.UUCP (Dale Worley) (09/22/87)

russ@crlt.UUCP (Russ Cage) writes:
> Skin
> effect can be dealt with by using flat conductors or Litz wire,
> or (again) *several parallel strands*.

As long as we're debunking things, note that the "skin effect" (if
it's the skin effect I know and love) involves a "penetration depth"
measured in fractions of a wavelength.  Since the wavelength at 20kHz
is ... hmmm ... 5 kilometers, it doesn't seem too significant.

Humor Dept.: I remember hearing about a great audiophile discovery
(I'm not making this up!): The electricity isn't conducted *in* the
wire itself, but in a cylindrical shell *around* the wire.  Of course,
this showed that to get *really good sound* you had to buy very
special (and very expensive) cables (from the company that made this
discovery).

Dale

brianr@tekig4.TEK.COM (Brian Rhodefer) (09/23/87)

The analog guru at the next desk assures me that, with today's
amplifiers, the dominant influence on the transient/frequency
response of the amplifier/cable/speaker electrical-to-pressure
transducing system is the series resistance of the speaker circuit.
He mentioned this by way of pointing out how profitless it is to
worry about small fractions of an ohm's worth of cable resistance
in the face of (typically) 4 ohms of intrinsic speaker coil resistance.

If this is so, why wouldn't it be a good idea to arrange for amplifier
outputs to look like current sources rather than voltage sources?
It ought to be quite simple to implement a current-sensing feedback system
so that the output stages faithfully translate audio program voltage
into speaker current,  within some reasonable (like +/- 60V or so) compliance.

Obviously, this would make the resistance of the speakers, as well as
the comparatively trivial cable effects, "drop out", by pulling these
imperfections inside the amplifier output stages' feedback loops.

It wouldn't be a total loss for the audiophiles, though: they could still
quibble about shunt losses due to distributed capacitance effects in their
cables - why, I'll bet they'd ammount to NANOFARADS!

Moreover, forces generated by currents passing through magnetic
fields tend to be simple products of the currents and field strengths.
A speaker's voice coil, then, should then have a linear current-to-force
transfer function.  As I'd expect voice-coil force to translate directly
into induced air pressure, it seems to me that a current-mode output
signal would also be desirable due to a more nearly linear transduction
of audio voltage signals into air pressure signals.

Am I mistaken in thinking that this is exactly the kind of transducer
that an amplifier/speaker system ought to be?

There must be some reason, though, for amplifier outputs to be made
the way they are;  could someone kindly explain why?



An Inquiring mind which may not really want
to know, but sure loves to ask dumb questions,

Brian Rhodefer

jeffw@midas.TEK.COM (Jeff Winslow) (09/23/87)

Let's be careful, debunkers...

In article <1549@culdev1.UUCP> drw@culdev1.UUCP (Dale Worley) writes:

>As long as we're debunking things, note that the "skin effect" (if
>it's the skin effect I know and love) involves a "penetration depth"
>measured in fractions of a wavelength.  Since the wavelength at 20kHz
>is ... hmmm ... 5 kilometers, it doesn't seem too significant.

According to a paper I have in front of me, skin depth at 1Ghz in copper
is .0002 cm, which is a *lot* less than a wavelength. And it is a fact
that windings in power transformers for switching power supplies running
at 20kHz must be oversized due both to skin effect and proximity effect.
I've designed several such supplies, and have worked closely with the
magnetics experts who designed the transformers.

>Humor Dept.: I remember hearing about a great audiophile discovery
>(I'm not making this up!): The electricity isn't conducted *in* the
>wire itself, but in a cylindrical shell *around* the wire.  Of course,
>this showed that to get *really good sound* you had to buy very
>special (and very expensive) cables (from the company that made this
>discovery).

Find a fields and waves book and look up Poynting's vector. Not that it
justifies this particular company's silliness, but it's probably the
source of their "justification".

		Jeff Winslow
		"Hit him again!!!" - Elektra/Strauss

jong@hounx.UUCP (J.LEE) (09/23/87)

In article <1549@culdev1.UUCP>, drw@culdev1.UUCP (Dale Worley) writes:
> As long as we're debunking things, note that the "skin effect" (if
> it's the skin effect I know and love) involves a "penetration depth"
> measured in fractions of a wavelength.  Since the wavelength at 20kHz
> is ... hmmm ... 5 kilometers, it doesn't seem too significant.
> 

The wave length of 20 K Hz tone is 5 kilometers???
Nah.  The velocity of sound is about 300 m/s at room temperature.
This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
or 1.5 cm (~0.6 in). Granted, this is still much larger than
most audio conductor diameter. As to whether this causes audible
phase dispersion or not, I am still not sure.  I am still
experimenting... .

Regards.    J Lee, Bell Labs, Holmdel, NJ.

rdp@teddy.UUCP (Richard D. Pierce) (09/23/87)

In article <1953@tekig4.TEK.COM> brianr@tekig4.UUCP (Brian Rhodefer) writes:
>The analog guru at the next desk assures me that, with today's
>amplifiers, the dominant influence on the transient/frequency
>response of the amplifier/cable/speaker electrical-to-pressure
>transducing system is the series resistance of the speaker circuit.
>He mentioned this by way of pointing out how profitless it is to
>worry about small fractions of an ohm's worth of cable resistance
>in the face of (typically) 4 ohms of intrinsic speaker coil resistance.
>

In part, your analog guru friend is quite correct, in that the series
electrical resistance in the voice coil is the dominant electrical loss,
but, as it turns out, it is but one of many total losses in the entire
system, and is not the dominant influence on the transient/frequency
response of the entire system.

>
>[A description of what amounts to an active loudspeaker feedback system
> that includes the effects of cable interface problems....]
>
>Moreover, forces generated by currents passing through magnetic
>fields tend to be simple products of the currents and field strengths.
>A speaker's voice coil, then, should then have a linear current-to-force
>transfer function.  As I'd expect voice-coil force to translate directly
>into induced air pressure, it seems to me that a current-mode output
>signal would also be desirable due to a more nearly linear transduction
>of audio voltage signals into air pressure signals.
>

Unfortunately for your theory, voice coil force DOES NOT translate directly
into induced air pressure. At its very best, voice coil force (and, hence,
voice coil current) translates into volumn velocity. The effective sound
pressure level is a complex function of frequency, due to the great
variations in sounf pressure level with frequency. (For direct radiator
loudspeakers, the radiation impedance goes roughly as the square of the
frequency while the driver is operating in its piston region. Below
mechanical resonance, the speaker is unable to maintain the constant
volume velocity, which is why they roll off. ABove the piston band, the 
radiation impednace is a complex and only partially understood consequence
of driver size, shape, baffle loading, diffraction, etc., etc.)

There is also the issue that the force generated by the voice coil in
practical drivers is not a linear function of voice coil current, even
ignoring frequency-dependent effects. This is due to non-linearities in
the mechanical suspension of the driver, non-linearities in the magnetic
field, etc.

>Am I mistaken in thinking that this is exactly the kind of transducer
>that an amplifier/speaker system ought to be?
>
>There must be some reason, though, for amplifier outputs to be made
>the way they are;  could someone kindly explain why?
>

AMplifiers are designed as voltage sources, because the vast majority of
loudspeakers have a varying impedance, yet, over the limited range of
operation, produce constant sound pressure for constant applied voltage.
At low frequencies, at and around mechanical resonance, the effective
electrical impedance is much higher than the nominal impedance. (I am, as
we speak, looking at the impedance curve for a 10" woofer that has an
impedance of 83 ohms at resonance, compared to a DC resistance of 3.2 ohms,
and a nominal impedance of 4 ohms. Its output, given a constant applied
voltage, at resonance is but 3 dB lower than that in the midband, because 
its in an enclosure that gives it a Q of .707. Note that the current flowing 
through the voice coil at that point is 1/20th the current flowing through it 
in the midband, some 26 dB less, yet the "efficiency" is the same.)

Dick Pierce

rdp@teddy.UUCP (Richard D. Pierce) (09/23/87)

In article <1130@hounx.UUCP> jong@hounx.UUCP (J.LEE) writes:
>
>The wave length of 20 K Hz tone is 5 kilometers???
>Nah.  The velocity of sound is about 300 m/s at room temperature.
>This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
>or 1.5 cm (~0.6 in). Granted, this is still much larger than
>most audio conductor diameter. As to whether this causes audible
>phase dispersion or not, I am still not sure.  I am still
>experimenting... .
>

Jesus f****ing Christ, boys and girls, could we PULLEEEEZE make sure we are
all talking about the same things, just maybe, huh?

Mr. Lee, you are absolutely correct, the velocity of sound is indeed about
300 m/sec (342 m/sec at STP, to be a bit more precise), but that has absolutely
not one wit to do with skin effect. Common, the original writer was making
a statement about electrical propogation in a cable, and what that has to
do with acoustical propogation is simple to understand: nothing!

Dick Pierce

larry@kitty.UUCP (Larry Lippman) (09/23/87)

In article <1130@hounx.UUCP>, jong@hounx.UUCP (J.LEE) writes:
> > As long as we're debunking things, note that the "skin effect" (if
> > it's the skin effect I know and love) involves a "penetration depth"
> > measured in fractions of a wavelength.  Since the wavelength at 20kHz
> > is ... hmmm ... 5 kilometers, it doesn't seem too significant.
> 
> The wave length of 20 K Hz tone is 5 kilometers???
> Nah.  The velocity of sound is about 300 m/s at room temperature.
> This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
> or 1.5 cm (~0.6 in). Granted, this is still much larger than
> most audio conductor diameter. As to whether this causes audible
> phase dispersion or not, I am still not sure.  I am still experimenting...

	Uh, we are talking about ELECTRICAL propagation of signals in
the 20 kHz frequency range.  So we are talking about velocities around
the speed of light, which is roughly 300,000,000 meters/sec.  So the
electrical wavelength of a 20 kHz signal is approximately 15 km long.
	SOUND propagates at roughly 300 meters/sec IN AIR at room
temperature.  We are not talking about sound propagation in copper wire!

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
<>  UUCP:  {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry
<>  VOICE: 716/688-1231       {hplabs|ihnp4|mtune|seismo|utzoo}!/
<>  FAX:   716/741-9635 {G1,G2,G3 modes}   "Have you hugged your cat today?" 

ornitz@kodak.UUCP (barry ornitz) (09/24/87)

In article <1130@hounx.UUCP> jong@hounx.UUCP (J.LEE) writes:
>In article <1549@culdev1.UUCP>, drw@culdev1.UUCP (Dale Worley) writes:
>> As long as we're debunking things, note that the "skin effect" (if
>> it's the skin effect I know and love) involves a "penetration depth"
>> measured in fractions of a wavelength.  Since the wavelength at 20kHz
>> is ... hmmm ... 5 kilometers, it doesn't seem too significant.
>> 
>
>The wave length of 20 K Hz tone is 5 kilometers???
>Nah.  The velocity of sound is about 300 m/s at room temperature.
>This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
>or 1.5 cm (~0.6 in). Granted, this is still much larger than
>most audio conductor diameter. As to whether this causes audible
>phase dispersion or not, I am still not sure.  I am still
>experimenting... .
>
>Regards.    J Lee, Bell Labs, Holmdel, NJ.

Just what goes on here?  Certainly the readers of wreck.audio have more
sense than this.  We are talking electrical wavelength here, not acoustical
wavelength.  The electrical wavelength is the speed of light divided by the
frequency multiplied by the velocity factor of the cable.  The velocity
factor is the reciprocal of the square root of the dielectric constant of
the wire insulation.  For polyethylene, as an example, the velocity factor is
about 0.66 and the wavelength at 20 KHz is about 32,500 feet.

Just what does acoustical wavelength have to do with speaker wire?  Maybe
since the resistance of the mercury filled wire is mechanical stress
dependent, acoustic waves impinging on the cable could cause resistance
changes leading to a form of acoustic (and electrical) cross modulation
which is certainly nonlinear and hence a no-no to audio phreaks.  Besides
the sonic velocity of a material is density related; it is much higher in
copper than in air.

BTW - I won't be sorry to see the Commander disappear but I will miss Pierce.

 -----------------
|  ___  ________  |
| |  / /        | |  Dr. Barry L. Ornitz   UUCP:...!rochester!kodak!ornitz
| | / /         | |  Eastman Kodak Company
| |< < K O D A K| |  Eastman Chemicals Division Research Laboratories
| | \ \         | |  P. O. Box 1972
| |__\ \________| |  Kingsport, TN  37662       615/229-4904
|                 |
 -----------------

drw@culdev1.UUCP (Dale Worley) (09/24/87)

jong@hounx.UUCP (J.LEE) writes:
> The wave length of 20 K Hz tone is 5 kilometers???
> Nah.  The velocity of sound is about 300 m/s at room temperature.
> This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
> or 1.5 cm (~0.6 in).

I meant, the electromagnetic wavelength.

Dale

yoon@gt-cmmsr.GATECH.EDU (Wan Yoon) (09/24/87)

In article <1130@hounx.UUCP> jong@hounx.UUCP (J.LEE) writes:
>
>The wave length of 20 K Hz tone is 5 kilometers???
>Nah.  The velocity of sound is about 300 m/s at room temperature.
>This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
>or 1.5 cm (~0.6 in).

 Wow, you are mentioning the skin effect of AIR, aren't you?

>
>Regards.    J Lee, Bell Labs, Holmdel, NJ.


-- 
Wan Yoon

UUCP:	yoon@gt-cmmsr.UUCP
        ...!{akgua,allegra,hplabs,ihnp4,seismo,ulysses}!gatech!gt-cmmsr!yoon
INTERNET:	yoon@cmmsr.gatech.edu

lew@ihlpa.UUCP (09/25/87)

In article <2032@kitty.UUCP>, larry@kitty.UUCP (Larry Lippman) writes:
> 	Uh, we are talking about ELECTRICAL propagation of signals in
> the 20 kHz frequency range.  So we are talking about velocities around
> the speed of light, which is roughly 300,000,000 meters/sec.  So the
> electrical wavelength of a 20 kHz signal is approximately 15 km long.
> 	SOUND propagates at roughly 300 meters/sec IN AIR at room
> temperature.  We are not talking about sound propagation in copper wire!
> 

Yes. And this is also why we don't hear a doppler shift of the audio
signal on a radio carrier when riding in a car.  We only move a small
fraction of the audio wavelength ( on the carrier ) during one audio
cycle. That's one way to think of it, anyway.

Of course, this fraction is independent of the wavelength and depends
only on the speed of the car relative to the source.




Lew Mammel, Jr.

farren@gethen.UUCP (09/27/87)

In article <1130@hounx.UUCP> jong@hounx.UUCP (J.LEE) writes:
>
>The wave length of 20 K Hz tone is 5 kilometers???
>Nah.  The velocity of sound is about 300 m/s at room temperature.
>This makes the wave length of 20 KHz sinusoid 0.015m (=300/20k)
>or 1.5 cm (~0.6 in). Granted, this is still much larger than
>most audio conductor diameter. As to whether this causes audible
>phase dispersion or not, I am still not sure.  I am still
>experimenting... .

I see!  They believe that it's *SOUND* travelling down the wire, not
electrons!  Well, that explains a *LOT* of things about rec.audio
fanatics!

:-), I suppose.


-- 
----------------
Mike Farren             "... if the church put in half the time on covetousness
unisoft!gethen!farren   that it does on lust, this would be a better world ..."
gethen!farren@lll-winken.arpa             Garrison Keillor, "Lake Wobegon Days"

cm450s02@uhccux.UUCP (jeff t. segawa) (10/04/87)

Bill Blue; I couldn't agree more with this business about tecnical specifications and subjective sound quality. I bought my first stereo based on those
distortion specs. Figured that if I had an amp that only produced .008%
harmonic distortion, it must be great at sound reproduction. Boy, was I ever
wrong. It sounded shrill and irritating--not at all like live music I have
heard. I also have a couple of CD players which have fantastic specs:
almost no noise, fantastic dynamic range, etc, but I still find them
(they're a couple of Magnavox players) somehow lacking when I compare them
to a 'tweaked' player by PS Audio, though the specs aren't much different,
Neither player, in my opinion, does as good a job at sound reproduction
as a really good cassette deck running first generation master tapes,
or my SOTA Sapphire turntable. Maybe the source of a lot of these
"looks good on paper, sounds awful" sort of problems have a lot to
do with the WAY these measurements are taken. For example, as I recall,
turntable speed accuracy measurements are done by playing 1Khz test  
tones. Servo motor powered turntables cope with this type of material
well, since tye stylus drag, and hence, the load imposed on the 
turntable's motor, is constant. Now get this same turntable, and try
playing a real record, with it's varying degrees of modulation, on it.
Hit a loud passage, and the stylus drag builds up. Platter slows down,
servo tries (too late) to compensate. I had a turntable like this.
With most types of top 40 music, it sounded OK. Couldn't figure out
why piano music always sounded somehow off key. Naturally, the spec
sheet told me that the turntable had nearly perfect speed accuracy,
and it did, so long as I played 1Khz test tones. If nothing else,
this incident taught me the value of trusting one's own ears.
As a result, I'm not too proud to admit that my system is made up,
among other things, of a Dyna PAS-3x (tube) preamp and Randall 
Research interconnects. Why? Simply because, tube noise and all,
the system does a better job at reproducing music that most   
other systems I have listened to.

bks@unisoft.UUCP (Brian K. Shiratsuki) (10/05/87)

In article <899@uhccux.UUCP> cm450s02@uhccux.UUCP (jeff t. segawa) writes:
>...Neither [cd ] player, in my opinion, does as good a job at sound reproduc-
>tion as a really good cassette deck running first generation master tapes...

what do you mean ``first generation master tapes'' on a cassette deck?  who
masters on cassettes, and where do you find these tapes?
-- 

				brian

rab@well.UUCP (Bob Bickford) (10/05/87)

jeff t. segawa writes:
+                                Maybe the source of a lot of these
+ "looks good on paper, sounds awful" sort of problems have a lot to
+ do with the WAY these measurements are taken. For example, as I recall,
+ turntable speed accuracy measurements are done by playing 1Khz test  
+ tones. Servo motor powered turntables cope with this type of material
+ well, since tye stylus drag, and hence, the load imposed on the 
+ turntable's motor, is constant. Now get this same turntable, and try
+ playing a real record, with it's varying degrees of modulation, on it.
+ Hit a loud passage, and the stylus drag builds up. Platter slows down,
+ servo tries (too late) to compensate. I had a turntable like this.
+ With most types of top 40 music, it sounded OK. Couldn't figure out
+ why piano music always sounded somehow off key. Naturally, the spec
+ sheet told me that the turntable had nearly perfect speed accuracy,
+ and it did, so long as I played 1Khz test tones. If nothing else,
+ this incident taught me the value of trusting one's own ears.

<sigh>  If you are able to detect *ANY* variation in the speed of *ANY*
turntable based on "stylus drag", then it's time to chuck the thing
in the trash.  Run the calculations yourself if you don't believe me;
the effect of the stylus is *at least* three orders of magnitude below
normal frictional forces (bearings, etc.).   Tell me you have a magnetically
levitated platter running in a vacuum chamber, and I *might* believe that
the effect of the "stylus drag" could be detected.
   Try to think before you say things like that, okay?   <sheesh>

  Robert Bickford                 {hplabs, ucbvax, lll-lcc, ptsfa}!well!rab

cm450s02@uhccux.UUCP (jeff t. segawa) (10/05/87)

In article <601@unisoft.UUCP> bks@unisoft.UUCP (Brian K. Shiratsuki) writes:
>In article <899@uhccux.UUCP> cm450s02@uhccux.UUCP (jeff t. segawa) writes:
>>...Neither [cd ] player, in my opinion, does as good a job at sound reproduc-
>>tion as a really good cassette deck running first generation master tapes...
>
>what do you mean ``first generation master tapes'' on a cassette deck?  who
>masters on cassettes, and where do you find these tapes?
>-- 
>
>				brian

At the stereo store I use to work at, one of the guys there was into live
recording, so when he had the chance, he would invite musician customers
to perform (in the sound room). Recording equipment generall included a
Nakamiche 550, Nakamichi BX300 and Sony SLHF900 Super Beta. (though not
all at the same time). 2 or 3 Nakamichi mikes were also used (using the
550 as a simple mixing board). The advantage of having these tapes is
that we knew just what the original performance was supposed to sound like
so we had an idea what the recording/playback equipment was or was not
reproducing faithfully. I have also done live recordings using a 
Nakamichi 500 and Sony SL5200 Beta Hi Fi. True, we probably would have
been better off using 15 or 30 ips open reel tapes, but we didn't have
access to one.

cm450s02@uhccux.UUCP (jeff t. segawa) (10/06/87)

In article <4139@well.UUCP> rab@well.UUCP (Bob Bickford) writes:
><sigh>  If you are able to detect *ANY* variation in the speed of *ANY*
>turntable based on "stylus drag", then it's time to chuck the thing
>in the trash.

Sure the stylus drag is probably small compared to other sources of 
friction, but aren't those other sources more or less constant, while
the stylus drag is anything but? Considering how tiny some of those
modulations in a typical record groove really are, I don't see why
it should be so hard to belive that tiny speed variations or 
resonances could have an audible effect on the sound. It's a shame
that I don't still have that turntable. I would've loved to let you
hear it for yourself.

pom@under..ARPA (Peter O. Mikes) (10/06/87)

Article 2362 (2 more) in sci.physics:
From: cm450s02@uhccux.UUCP (jeff t. segawa)
Newsgroups: rec.audio,sci.physics,sci.electronics
Subject: Re: Mercury Filled Speaker Wire

||References: <3816@watdcsu.waterloo.edu> <578@uthub.toronto.edu> <1700@crash.CT
||S.In article <4139@well.UUCP> rab@well.UUCP (Bob Bickford) writes:
||<sigh>  If you are able to detect *ANY* variation in the speed of *ANY*
||>turntable based on "stylus drag", then it's time to chuck the thing

>Sure the stylus drag is probably small compared to other sources of 

  Could you audio-maniacs PLEASE take this chronic debate off the sci.physics
  and confine  it to rec.audio.opinion.. group? It had no physics in it to start
  with and is getting more and more boring every month...  Thank you


     Yours  Peter || pom    at     pom@under.s1.gov ||  pom@s1-under.UUCP 

rees@apollo.uucp (Jim Rees) (10/06/87)

    what do you mean ``first generation master tapes'' on a cassette deck?  who
    masters on cassettes, and where do you find these tapes?

[ I have removed sci.physics from the list ]

I have one at home.  I have friends in the recording industry, and I
was at a local recording studio a few weeks ago while they were mixing
a new release.  Standard practice these days seems to be recording on
a 24 (or so) track analog deck, then mixing down to digital via VCR.
The mixing board has a control track that sets up the mixer boards,
so it's very easy to replay a particular mix.  You can even set up
several different mixes if you want to sacrifice the tracks.

I talked the engineer into doing a mix direct from the original tape
onto cassette for me.  We used chrome tape with Dolby C.  My home
cassette deck is an el-cheapo (~$120) Technics, but I have to say
that it sounds pretty good when playing this particular tape.

The point is that they had several cassette decks in the studio, and
I got the impression that they master onto cassette all the time.
Not to send the tape to the record presser, of course, but to give
the musician something to take home, or to make a demo tape, or
whatever.

klm@munsell.UUCP (Kevin (my watch has a touch screen) McBride) (10/07/87)

In article <601@unisoft.UUCP> bks@unisoft.UUCP (Brian K. Shiratsuki) writes:
>
>what do you mean ``first generation master tapes'' on a cassette deck?  who
>masters on cassettes, and where do you find these tapes?
>
>				brian


Well, Bruce Springsteen recorded one of his albums in the living room
of his home on a four track cassette recorder.  (I think it was "The
River", but don't quote me on that.)

You know what?  The whole album sounds like it was recorded in the
living room of his home on a four track cassette recorder.
Can you say "lousy dynamic range"?  Can you say "tape hiss"?
Can you say "It sounds like he's singing into a toilet bowl"?
I thought you could.

It was one of his less impressive works. (Not that ANY of his recent works
could be labelled "impressive".  I like the "Old" Boss.)

(Donning my asbestos suit just in case.)

-- 
Kevin McBride         | "Is that a real     | harvard -\
I/O Software Group    |  poncho, or is that | ll-xn ---adelie----> munsell!klm
Eikonix - A Kodak Co. |  a Sears poncho?"   | decvax -v talcott -v   |
Billerica, MA         |     - Frank Zappa   | allegra ------------encore

georgep@vice.TEK.COM (George Pell) (10/08/87)

Seems to me that using wire is the wrong way to go.
What you need is a transmission line!  Lets see...

.062 dual clad G10 material, 2 oz copper, .367 wide traces.

Where can I get a 1" by 15 foot pc board?????