[net.audio] Random stuff...

francini@argus.DEC (This Space Available for Rent or Lease) (08/31/85)

Just some random observations/comments/questions...

I've seen a lot of comment about 'Don't Buy a Technics CD player' here.  
This is very entertaining.  My wife and I bought a SL-P7 no-frills unit a 
year ago this weekend.  It continues to work flawlessly, and the sound 
quality is (to my ears) quite good.  (Then again, what do I know?  Our 
system has Klipsch Heresy speakers.  [I married into them.] :-) )

The whole concept of digital audio inspired my wife to decide to do a 
180-degree career change from secretary to audio/video repair.  She is now 
attending an electronics school out here in the Boston area (Sylvania 
Technical School), and will graduate in a year.  

Speaking of speakers, I'd like to know what everyone in netland thinks of 
Walsh-driver based speakers, namely the Ohm Walsh-1, -2, and -4 series.  I 
have listened to them at a friend's house and have been quite impressed 
with the imaging, no matter where I stood/sat in the listening room.

Also, has anyone listened to the CD version of the soundtrack of "E.T."?  
If so, any opinions?

...

>...16 Bit PCM direct-to-brain for us all...
>Terry Zrust

Probably by then it will be 32-bit.  That will give much better resolution 
and far less problems with finicky filters and the like.
 
 
>> It would be nice if someone, someday said that measuring parameter YYYY
>> translates to sound ZZZZ.  A hypothetical listing of this translation follows:
>>  
>> Measured Parameter            Sonic result
>> 
>> Damping Factor                Higher factors reduce muddiness
>> Slew Rate                     Higher slews improve crispness
>> Signal-to-noise ratio         Higher ratios improve low-level resolution
>> Supply Regulation             Better regulation improves imaging
>> Supply Ripple @ full power    Lower ripple improves focus
>> Supply Impedance vs. Freq.    Linear impedances improve inner detail
>> Chassis Leakage @ full power  Lower leakage improves low-level resolution
>> Phase vs. Freq.               Low shifts improve inner detail
>> 
>It would also be nice if someone, someday said what "focus" and "inner detail"
>mean!
>            Dave Wagner

About a year or so ago there was an issue of _Stereo Review_ that had an 
article that attempted to define a large number of subjective terms having 
to do with the 'sound' of things.  This might be a good start.

...

>...My musical preferences are baroque keyboard music, including
>organ (I have measured SPL's of REAL pipe organs, they are NOT very loud).
>
>Dick Pierce

Funny... when I got married two years ago, in a big church with a large 
pipe organ, I couldn't hear myself THINK over the organ when the organist 
was playing in earnest (during the procession and recession).  

I would be curious to know what the conditions of the organ measurement you 
did were.  Was it a during a public performance or was it a special session 
with not more than you, the organist, and the measuring equipment present?
Also, what size was the organ?  Obviously, bigger organs are going to sound 
louder.  Maybe I'm suffering from a misconception brought on by too many 
Catholic masses, but I always thought that the Pipe Organ is by far the 
loudest non-amplified instrument.  (Now, before I get flamed, this is a 
subjective opinion.  Maybe there are others that emit a higher SPL, but the 
organ is the most commanding instrument in my mind.)

John J. Francini

...decvax!decwrl!dec-rhea!dec-argus!francini

"Remember, the Force will be with you, always."

rdp@teddy.UUCP (09/03/85)

In article <253@decwrl.UUCP> francini@argus.DEC (This Space Available for Rent or Lease) writes:
>
>Funny... when I got married two years ago, in a big church with a large 
>pipe organ, I couldn't hear myself THINK over the organ when the organist 
>was playing in earnest (during the procession and recession).  
>
>I would be curious to know what the conditions of the organ measurement you 
>did were.  Was it a during a public performance or was it a special session 
>with not more than you, the organist, and the measuring equipment present?
>Also, what size was the organ?  Obviously, bigger organs are going to sound 
>louder.  Maybe I'm suffering from a misconception brought on by too many 
>Catholic masses, but I always thought that the Pipe Organ is by far the 
>loudest non-amplified instrument.  (Now, before I get flamed, this is a 
>subjective opinion.  Maybe there are others that emit a higher SPL, but the 
>organ is the most commanding instrument in my mind.)
>
>John J. Francini
>

Yes, I should have been more specific. There do exist large organs which,
with injudicious registration, are capable of irritatingly loud noises
(almost a prejudice, but not quite). I have measured the SPL of large
organs (The large Fisk organ in Harvard Memorial Chapel, the Frobenius
instrument in the Congregational Church in Cambridge, the (to me) huge
Welte organ in the Church of the Covenant in Boston, etc. ). In all
cases where the organist had made proper registration selections (ie.
not pulling every stop simply for effect), the sound pressure seldom
exceeded 85 db SPL in the closest audience seating. I am very sure,
however, that a sizable majority of organists simply do not know how
to register accordingly. The net result of pulling all stops does not
substantially increase SPL, interestingly enough. Several reasons are
behind this, not the least of which is the fact that doing this causes
the organ to, quite literally, run out of air, which causes a reduction
in acoustic output per pipe and mistuning. Very complex non-harmonic
junk is generated and the net result is something which, while not having
huge amounts of acoustic power, SOUNDS very loud, and quite irritating.

Sorry for the confusion

Dick Pierce

rfg@hound.UUCP (R.GRANTGES) (09/04/85)

[]
Re: quiet organs (If they are loud, the organist is using the wrong registration

Tell us about the SPL of the state trumpet at St. John the Devine. Measured on
the floor of the Nave at the rear.

Funny. I thought many composers wrote passages (now and then) for full organ
or thereabouts. I guess they just didn't know their registrations either.
Last time I saw John Bach I took him to task for the registration of his
Toccata and Fugue in D Minor. It lets all the wind out. He said he intended it
to do just that. If an organ had "good lungs" it wouldn't run out of breath.

It is certainly true that many organ pipes are not terribly loud.  But
pipe organs are like cars.  They come in all sizes, colors and horsepower.
It is certainly possible for someone to consider anything but a VW
Beatle as too large, overpowered and vulgar.  But to represent that as
a universal opinion is somewhat mistaken.

Many pipes are individually quite loud - especially those designed for
high wind (air) pressure. Then, when they are played together, you are
going to get power law addition. Many classical organs contain groups
of pipes designed to speak (play) together as one note. These are called
"mixtures" and "mutations." It is easily possible to play dozens of pipes
simultaneously, whether some people like it or not. Many people <do>
like it and that's why the organ was built that way.  Large organs are
capable of generating, are intended to generate, and <do> generate when
played by competent organists very large quantities of sound, much of
which comes at high sound pressure levels (spl).  I have heard organs
so loud that the inner ear mechanism would "decouple" in an effort
at self preservation.  I have heard bass notes so loud that you could hear
the non-linear distortion generated in your own ears. The loudest such
I recall hearing was a demo of an electronic organ at school many
years ago.  It may not have sounded good, but it was certainly loud.

Reminds me of the famous Hammond Organ story. Now most organ people
always considered the old tone wheel Hammond Organ to sound like sh*t.
And no one ever thought one would be mistaken for a pipe organ. During
the '30's someone challenged Hammond to a test. A Hammond was installed
in a church with a good pipe organ and an audience of dignitaries
was convened to judge which was the pipe organ just by listening. Guess
who won.  Hammond hired a genius performer and installed huge amplifiers and
zillions of speakers. The audience concluded that the Hammond was the pipe
organ, mostly because it was louder.

Now the information in this note will not be news to the gentleman who
said that organs were really quiet. I don't know why he chose his
extreme position. I don't carry spl meters in my pockets, especially to
church services.  But when I used to attend Riverside church just to
hear Virgil Fox play the organ, I know it was beautifully loud. When
the chord sort of picks you up and moves you gently back and forth on
the floor, there are spl's at work that would cause the man from osha(sp)
to get all sweated up, and it takes more than 85 db to do that.

-- 

"It's the thought, if any, that counts!"  Dick Grantges  hound!rfg

copp@petrus.UUCP (09/04/85)

Nice polemic, rfg, but do you have any data?

rdp@teddy.UUCP (09/04/85)

In article <1343@hound.UUCP> rfg@hound.UUCP (R.GRANTGES) writes:
>[]
>Re: quiet organs (If they are loud, the organist is using the wrong registration
>
>Tell us about the SPL of the state trumpet at St. John the Devine. Measured on
>the floor of the Nave at the rear.
>

Fine, it is REAL damned loud, but it is very much the exception rather than the
rule.

>Funny. I thought many composers wrote passages (now and then) for full organ
>or thereabouts. I guess they just didn't know their registrations either.
>Last time I saw John Bach I took him to task for the registration of his
>Toccata and Fugue in D Minor. It lets all the wind out. He said he intended it
>to do just that. If an organ had "good lungs" it wouldn't run out of breath.
>

Well, let's look at some of the organs that Bach knew (I have played several
of them myself, thank you) Yes, he did require that the instrument have good
lungs, (an admonition, I believe, about the organ at Mulhausen, which was
not very large by the extant standards). When played altogether, the actual
SPL is still not very loud.

As to composers recommendations for "full organ" (known in the baroque
era as organo pleno) there exists some very specific registrations by
those composers. They never include every singlee stop. Remember that they
achieved dynamics with tone color as much as with actual acoustic pressure.
I would suggest you read such texts as (I believe the title is correct)
"The Organ in the French Classical Tradition", by Fenner Douglass, as well
as several texts regarding registration techniques in Northern Europe
during the Late Baroque. All of these texts quoate specific composers and
organ builders (including the likes of J. S. Bach and Arp Schnitger) on
registration techniques. All of them admonish the user from using thick,
heavy "full" registrations. Even still, I have played many of these 
instruments (including the Schnitger organ at St. Laurenskerk in Alkmaar,
Holland, which is a very BIG instrument, 4 manuals, 60 some-odd ranks,
bunches of mixtures and reeds, etc) and they are not loud as you describe
them.

>It is certainly true that many organ pipes are not terribly loud.  But
>pipe organs are like cars.  They come in all sizes, colors and horsepower.
>It is certainly possible for someone to consider anything but a VW
>Beatle as too large, overpowered and vulgar.  But to represent that as
>a universal opinion is somewhat mistaken.
>

I am representing observations of many (100's) of instruments I have
personal experience with. Some big, some small, some in between.

>Many pipes are individually quite loud - especially those designed for
>high wind (air) pressure. Then, when they are played together, you are
>going to get power law addition. Many classical organs contain groups
>of pipes designed to speak (play) together as one note. These are called
>"mixtures" and "mutations."

For your information, a "mutation" stop is almost always a single rank,
that is not either a unison or an octave of the fundamental pitch. For
example, 2 2/3', 1 3/5', etc., are mutations, whereas 8', 4', 2', etc.
stops are not. Mixtures can be composed of both octave-sounding and mutation
stops.

The purpose of well thought out mixtures is not to make the instrument
louder. They exist to compensate for several effects such as the loss
of sensitivity of the ear to very high and very low notes, absorbtion,
and so forth. The formula for the conposition of these mixtures was
developed empirically over nearly 500 years. Until the very late romantic
period (1900 on) they were used primarily for adding tone color, fullness,
etc. 

>It is easily possible to play dozens of pipes
>simultaneously, whether some people like it or not. Many people <do>
>like it and that's why the organ was built that way.  Large organs are
>capable of generating, are intended to generate, and <do> generate when
>played by competent organists very large quantities of sound, much of
>which comes at high sound pressure levels (spl).  I have heard organs
>so loud that the inner ear mechanism would "decouple" in an effort
>at self preservation.  I have heard bass notes so loud that you could hear
>the non-linear distortion generated in your own ears. The loudest such
>I recall hearing was a demo of an electronic organ at school many
>years ago.  It may not have sounded good, but it was certainly loud.
>


The advent of these gargantuan instruments did not occur until the late
19th, early 20th century. The bulk of organ literature was composed before
then (Please don't flame me on this, I have the catalogs to prove it)
Many of these organs have little to do with the correct performance of
organ music. During this period, organs were more important as orchestral
substitutes than as vehicles for the interpretation of the literature.
These behemoths (including the likes of Riverside) began appearing every-
where, such as international expositions (to show off the technological,
not musical, prowess of a country). They sprang up in convention halls
and even department stores (what is an organ doingin a department store?)
Organists and their instruments could claim the ability to do anything.
I belive it was Lynwood Farnham who could boast of the ability to make the
organ at Trinity Church in Boston sound like a train pulling out of a 
station. Wurlitzer advertized theater and church organs that could sound at
once like the raging of a thunderstorm or the whisper of a breeze.
The organ in the Auditorium at Atlantic City had a Stentorphone that was
blown with 100 inches of wind. Skinner was reputed to have a French horn
that was indistinguishable from the orchestral real thing.

So what?

Yes, there do exist instruments that are capable of almost dissasociating
air molecules. But they are very much in the minority. The trend in the
latter half of the 20th century has been to understand the literature,
the build the organ to suit. The result has been organs that run on all
of 2 1/2 to 3 inches of wind, that have NO loud solo stops, that have
chorus ensembles that generate their effects through the availability
of varying tone colors and are far less concerned about blowing the
windows out.

I will gladly acknowledge the existance of organs of the type you describe,
but I will disagree with you on several points. First, they are not the
norm, nor are they even the penultimate media of musical expression. 
Secondly, they are not suitable for the proper interpretation of the vast
bulk of classical organ literature. The days of the likes of Virgil Fox
driving home the final Tocatta of the D minor Tocatta and fuge on the
entire organ led by the Trumpet Magna are coming to an end, thankfully.
To admit that this style is the way such pieces should be performed is to
simultaneously admit that Bach himself could not perform it properly.

>Now the information in this note will not be news to the gentleman who
>said that organs were really quiet. 

I never said "organs are really quiet". I said that they are not as loud as
people assume.

>I don't know why he chose his extreme position. 

I did not choose an extreme position. I spent 3 years researching pipe organs,
5 years studying classical organs 1 year recording, repairing and playing
organs in Belgium, Holland, Germany and France, and most of my adult life
going to organ concerts.

>I don't carry spl meters in my pockets, especially to
>church services.  

Neither did I. I asked for permission to spend considerable time with more
sophisticated tools than a simple SPL meter measuring the instruments.

>But when I used to attend Riverside church just to
>hear Virgil Fox play the organ, I know it was beautifully loud. When
>the chord sort of picks you up and moves you gently back and forth on
>the floor, there are spl's at work that would cause the man from osha(sp)
>to get all sweated up, and it takes more than 85 db to do that.
>

For peoples general information, 85 dB SPL at the ear is quite loud. I
have yet to come across a pipe organ of any description (including sitting
inside the case) that produces anything even remotely approaching a small
night-club amatuer rock group.

Dick Pierce

Note. I actually find this discussion quite invigorating. I have (I don't
mean to brag) quite a lot of experience with organs and I find them quite
fascinating, and I enjoy talking about them quite a bit. If the Mr. Grantges
feels up to it, so do I.

By the way, if anyone is interested, 200 lbs of TNT set of 200 feet away
produces a peak acoustic level of 200 dB. So there!

rfg@hound.UUCP (R.GRANTGES) (09/05/85)

[]
What sort of data would you like, copp?
Go take your spl meter to St. John the Devine and measure it
yourself. Be sure to ask them to play only one note at a time
as it might hurt your hearing standing 50 ft below the pipes
or so.
Perhaps you would like a Reference? Try Olson, Musical Engineering,
first edition, page 231. Intensity Ranges of Musical Instruments.
You will find a chart showing up to perhaps 110-115 db for organ at
10 ft. Bass Drum and Kettle drum are similar. On pp. 205,206 there
are some interesting and instructive plots of average pressure per
cycle and peak to average ratios vs frequency for a wide variety
of instruments, including 15 and 75 piece orchestras.

Last, but not least, consider your own experience.  I assume you
listen to music sometimes. Recall the occassions when a symphony
orchestra going full tilt has been overwhelmed by a chord of
full organ -or maybe less than full. If you don't listen to
classical, try Saint Saens Symph No.3 Ormandy Telarc CD 80051
Last movement should convince you that organs are loud.

Next, lets consider the proposition: Broadly speaking, the nearest
star (the sun) exhibits a tendency, when observed from earth to
rise in the east. Bring data.

-- 

"It's the thought, if any, that counts!"  Dick Grantges  hound!rfg

rdp@teddy.UUCP (09/05/85)

In article <1345@hound.UUCP> rfg@hound.UUCP (R.GRANTGES) writes:
>[]
>What sort of data would you like, copp?
>Go take your spl meter to St. John the Devine and measure it
>yourself. Be sure to ask them to play only one note at a time
>as it might hurt your hearing standing 50 ft below the pipes
>or so.

Why do we insist on picking the pathological examples to illustrate
the norm?

>Perhaps you would like a Reference? Try Olson, Musical Engineering,
>first edition, page 231. Intensity Ranges of Musical Instruments.
>You will find a chart showing up to perhaps 110-115 db for organ at
>10 ft.

OK, let's see..

These SPL's were measured 10 ft away. Now, let's stand 50 feet away.
The intensity varies as the inverse square of the distance, so we have
a reduction in SPL of a factor of 25, etc. etc. Of course this do not take
into account absorbtion, etc.....

Then again, if Olson was talking 10 feet away from the pipes in the kind
of organ that he was measuring (large, enclosed Romantic beast), then the
SPL that actually reaches the floor is even less. Not much ever found there
way out of them things.

 Bass Drum and Kettle drum are similar. On pp. 205,206 there
>are some interesting and instructive plots of average pressure per
>cycle and peak to average ratios vs frequency for a wide variety
>of instruments, including 15 and 75 piece orchestras.
>
>Last, but not least, consider your own experience.  I assume you
>listen to music sometimes. Recall the occassions when a symphony
>orchestra going full tilt has been overwhelmed by a chord of
>full organ -or maybe less than full. If you don't listen to
>classical, try Saint Saens Symph No.3 Ormandy Telarc CD 80051
>Last movement should convince you that organs are loud.
>

Note in my previous posting, that I alluded to the fact that the instruments
Mr. Grantges refers to did not come into being until quite recently (last
100 years or less). There was almost no music written for combined organ
and orchestral music up until then. The most notable exception being the
Handel Organ Concertii. If we examine his organ at Great Packington, we find
it to be a small, quiet sedate, and, even compared to its contemporaries,
fairly quite. As a result, the total ensemble was small and relatively
quite. There were very, very few of the gargantuan instruments of the kind
that recent recordings of the likes of St. Saens have used in combination
with the gargantuan ensembles. Even Camille St. Saens own instrument (the
Cavaille-Cole organ in St. Sulpice) would cower under what Mr. Grantges
would consider the "average" organ.

AS an attempt at something other than conjectured proof, I have, at my
disposal, the specifications of some 1000 instruments scattered across
the Western Hemisphere. If anyone is interested, I might be coerced to
go through and see just exactly how many of these fit the mold that
Mr. Grantges is purporting to be the norm of organ size. So far, he has 
pointed to (I recall) only two specific instruments, the organ in St. John
the Divine and that in Riverside church.

Let's look through a Schwann catalog over the last decade and see what sort
of instruments the Complete organ works of the likes of Bach, Buxtehude,
Couperin, Dandrieau, D'Aquin, Frescobaldi, Sweelink, Bohm, Pachelbel, Handel
DeGrigny, Walther, Clerembaut, Byrd, Gibbons, Praetorius, Bruhn, Soler,
and even the likes of Cabezon are played on (there is a list of organ composers
that are, conservatively speaking, responsible for several thousand
individual and unique works!) Are they performed on the likes of the Atlantic
City Hall organ? No. How about St. John the Divine or Riverside? No, you
loose again. Well, what is typical for an instrument playing such works?
It seems such an instrument has 2 to 3 manuals, about 25 ranks, out of which
only 2 or 3 are reeds, and those are often things like Schalmei's or
Regals (which are REALLY quiet!). THey have relatively small mixtures (3-4
ranks) and they do fall well within the ranges I have previously described
for acoustic levels, even for "organo pleno". Note that organs (again, until
fairly recently) had stops which were very closely balanced in power output
but differed primarily in tonal color. The intent was to be able to (within
reasonable limits) be able to combine stop families into a cohesive, but
not overpowering, whole.

Further proof, if you so desire. I have access to the Aeolian-Skinner
organ in the Groton School. I have been in there, at the console, holding
a conversation in only slightly elevated tones whilst he played along "tutti">
There was no need to shout to be heard. The sound pressures simply weren't
that high, as my own extensive measurements have born out.

As an aside, exploring musical theory reveals why the organ-orchestra
(as well as most instruments used in ensemble with organs) are fairly
rare. Organs are forced to a fixed temperement, which in these less than
enlightened days, is almost always equal temperement, with the result that
there is almost no pure intonation possibilities (the octave being the sole
case). Orchestral instrumental players, whether they know it or not, (and
many don't seem to), tend to play there instruments in a modified just
intonation scheme, resulting in much purer chords and generally clearer
harmony. The two together tend to sound quite discordant. The problem didn't
effect Handel because his organs were tuned in a form of meantone temperement,
which might be considered a subset of just intonation.

>Next, lets consider the proposition: Broadly speaking, the nearest
>star (the sun) exhibits a tendency, when observed from earth to
>rise in the east. Bring data.

Sure thing, R., I'll have it there, first thing tomorrow morning. Be
up early, OK?

Dick Pierce

dep@allegra.UUCP (Dewayne Perry) (09/06/85)

<pipe down on that munching>

A few nits about Pierce's response to Grantges.  I dont recall whether
either one has mentioned that to a certain extent the loudness of an
organ is independent of the number of ranks - eg a 6 rank small
church organ can be built to put out a sufficiently large sound to
support congregational singing in a church of a 1000.

Second, Fox's way of doing Bach is independent of whatever Bach did.
If Fox can pull it off with a monstrous organ interpretation instead
of a small baroque organ interpretation - and I think that he did -
then fine.  There is more than one way to skin[ner] a cat.  Who
knows what Bach would have done if he had been organist at Riverside.
I do grant that Fox certainly was not of the 'authentic instrument'
school.

Stop - Dewayne Perry

rfg@hound.UUCP (R.GRANTGES) (09/06/85)

[]
I, for one, don't get up tight, when misquoted and misinterpreted.
Those who wish to listen to organ music at 85 db or less are perfectly free
to do so.  I, and probably most others, will continue to reproduce it at the
original levels, when possible. These are frequentlt well in excess of 90 db.-

-- 

"It's the thought, if any, that counts!"  Dick Grantges  hound!rfg

crandell@ut-sally.UUCP (Jim Crandell) (09/09/85)

In article <1349@hound.UUCP> rfg@hound.UUCP (R.GRANTGES) writes:
>I, for one, don't get up tight, when misquoted and misinterpreted.
>Those who wish to listen to organ music at 85 db or less are perfectly free
>to do so.  I, and probably most others, will continue to reproduce it at the
>original levels, when possible. These are frequentlt well in excess of 90 db.-

You're referring to the Royal Albert Hall organ, of course.  [:-)]

Down to brass tacks (NPI), a realistic level depends on the particular
instrument, not to mention the position of the listener.  I well remember
having to stuff cotton in my ears while regulating the Great Superoctave and
Mixture -- buried deep in a swell box (on the rear wall, in fact) -- of
an old and extensively kluged Austin.  Such a horrendous screeching I've
never before or since heard in an instrument of that period (ca. 1918).
But the sound in the church was another matter entirely; oddly enough,
it wasn't bad at all.  Incidentally, nothing on that small three-manual
organ came to anything like 90 dB from the congregation's vantage point.
-- 

    Jim Crandell, C. S. Dept., The University of Texas at Austin
               {ihnp4,seismo,ctvax}!ut-sally!crandell

rdp@teddy.UUCP (09/09/85)

In article <1349@hound.UUCP> rfg@hound.UUCP (R.GRANTGES) writes:
>[]
>I, for one, don't get up tight, when misquoted and misinterpreted.
>Those who wish to listen to organ music at 85 db or less are perfectly free
>to do so.  
>

Well, OK, then one final salvo. This weekend I took a GenRad 1565-B 
sound pressure level meter to the Groton School Chapel, which just happens
to have one of G. Donald Harrison's more famous "American Classic"
instruments in it. I played a few chords from just notable works as
the Bach D minor T&F, the G minor Fantasia and Fugue, some Dandrieau,
some Couperin, & the like. Using a registration consisting of the complete
Great principal chorus (principals 16', 8', 4', 2 2/3' 2', Fourniture V)
Plus a mojor portion of the Fulte chorus (bourdon 16', Cornet V), plus
the Cymbal IV, plus the complete reed chorus (Bombarde 16', trompette 8',
Clarion 4'), the complete pedal division, coupled to the Great, with all
reeds, thje maximum SPL I read in real chords was

	88 db SPL at the console (45 feet from the pipes)

> I, and probably most others, will continue to reproduce it at the
>original levels, when possible. These are frequentlt well in excess of 90 db.-

I, and probably few others, will continue to reproduce it at the 
original levels, when possible. These are seldom in excess of 88 dB.

If you find difficulty with this figure, please don't bitch to me. Try the
NBS, who is responsible for the calibration of this instrument.

Enough, OK?

Dick Pierce