raan@hp-pcd.UUCP (raan) (04/05/85)
I thought I would share some experiences with various audio accessories
and gadgets.
Tiptoes -- from Mod Squad
These are cone shaped hunks of aluminum which are placed point down
under your speakers (usually 4 per speaker). The theory is that they
will provide tighter coupling to your floor than the speaker has
when sitting on the carpet (the point goes through the carpet to the
floor beneath). This is supposed to improve the low end response.
I *think* I could detect a difference in the sound, but it is subtle
enough that it could be my imagination. As noted below, setup is
not easy, so A/Bing the combination is hard to do. I won't make
any claims about whether or not they work. I do want to share
what I learned about setting them up.
These cones are extremely unstable unless properly installed. If the
speakers are heavy, this will take at least two and maybe three people.
One to lift the speaker and one (or two) to position the cones under
it. I found that the surface the flat side of the cone is placed against
must be FLAT and parallel to the floor. If your speaker has feet on it
that are not at least as wide as the flat end of the cone, you will have
to remove the feet. After experimenting with various feet (ranging from
1/4" thick 3/4" round rubber screw mounted to 1/16" thick stick-on rubber)
I found that the best results were obtained with no feet at all. To
obtain better coupling between the speaker and cones (and aid in their
installation) I put a layer of double stick carpet tape on the surface
of the cone (this is a thin solid [not foam] plastic tape).
Omega One anti-static mat -- from Sound Saver
This is a stiff 1/16" thick carbon fiber mat that fits snugly around the
center post over the turntable mat.
It is supposed to drain away static charge on the record. I found that
it does work. It has no discernable affect on the sound, and is the
only anti-static item I have found that was really effective.
One drawback is that it occasionally sheds carbon fibers onto the underside
of the record. These fibers are conductive, so be careful not to get them
into electronic equipment.
Geodisc cartridge installation guide
This is a plastic, record sized device with markings for setting the
overhang and tracking angle on a cartridge (for tangental tonearms).
I have no way to double check the alignment of the cartridge as set up
by using this aid, but the result sounds good and it really is easy to use.
stereo remote control -- from AR
This is a small box (4x2x10) with indicator leds and an infrared remote
control unit. The box has a power outlet capable of handling 600W, a
main input and output, a tape loop, and a processor loop. It is installed
in the audio path between preamp and amp, or in a tape/processor loop.
Any compenents to be powered through it are plugged into the outlet.
It could also be used as a simple preamp.
The unit itself has a pushbutton switch for selecting the tape input.
An led indicates reception and processing of a signal from the remote
control (ie, if volume is already up all the way, the led does not
light -- even when receiving a volume up signal).
The remote control allows control of:
power -- the unit and anything plugged into the power outlet can
be turned on, off, and set for delayed off (30 minutes).
An led indicates that power is on. The receive led blinks when
the delayed off is in affect. Any other signal cancels this mode.
mute -- the unit has two mute levels, low or completely off.
An led indicates when the unit is muted.
balance -- the unit can vary balance to left or right in 1 db steps.
It can also set balance all the way to left, right, or center on
command. An led indicates when the channels are balanced.
processor loop -- the unit can switch the incoming signal to be
routed through an external processor, and then back through the
unit and out to the amp. This can also be used to select a
second source. An led indicates when the processor loop is
active.
volume -- the unit can vary the volume in 1 db steps. It goes from
full off to maximum as determined by volume setting on the preamp.
The rate of change can be fast or slow.
I found this to be a very useful addition to my system. It works well,
adds very little noise (much less than either of the other units below),
is flexible, and very handy when the phone rings, etc. The abilty to
switch the processing loop in and out is very useful for comparing the affect
of processors from your favorite listening chair. In fact, I liked it so
much I bought a second one for the bedroom system. I use the processing
loop to select the tv audio, giving me remote control volume for the tv.
120 subharmonic synthesizer -- from dbx
This is a processing unit which contains a low frequency boost, an active
crossover, and a subharmonic synthesizer. It has a main input and output,
a low frequency output, leds to indicate power and synthesis activity, and
control for low frequency boost and synthesis level.
The unit works by taking all frequencys in the range below 60 hz, halving
them, and outputing the resulting frequency in addition to the original.
It also boosts the low frequency in a much more controlled fashion than
the bass control on a preamp. The synthesis can by bypassed, but the boost
is always active. Both boost and synthesis can be reduced to zero or
increased to absurdity. When the low frequency output is selected, the
result of the boost and synthesis is feed to it and the unprocessed signal
is feed to the main output.
The results of this process are interesting. For music with little bass,
it has no affect. For music with noticable bass, you can get a *lot*
more. My speakers do pretty well in the bass range alone, but I was
contemplating adding a sub-woofer. With this unit, I don't need one.
When pushed too far, it makes male voices sound like they are in a metal
barrel with gravel on the top (a rattling reverberation), but properly
adjusted it does enhance the bass a noticable amount.
It does have one drawback. It introduces a certain amount of low freq
noise into the system. This is only noticable during quiet times (ie
normal room noise will drown it out) and sounds like a ground loop.
DNR noise reduction, stereo synthesizer and expander -- from Radio Shack
I bought this mostly for the DNR circuit. It is has inputs for tv,
vcr (to the stereo synthesiser), tape input and output, main input and
output, and controls for adjusting/selecting the DNR level, synthesis,
expansion level and input.
The synthesis level works by breaking the input into 5 frequency bands
and sending alternating bands to opposite channels. It works, although
producing strange effects with certain types of inputs.
The expander plays with phasing and cross channel mixing, the affect is
interesting, but I don't like it very much (it makes a piano sound
10 feet across). It also introduces a *lot* of noise when engaged
(this noise is present even when the expander is bypassed, the only
way to get rid of it is to turn the expansion level all the way down).
The noise is a kind of reverberating hum.
The DNR portion works by cutting all frequencys above a certain frequency
and below a given volume level. The cutoff is controllable by the user.
This actually works fairly well. The level is very sensitive, too much
and you get strange effects (no treble until a loud passage and then
lots of hiss, etc), too little and no effect at all. If properly adjusted,
it does a reasonable job of reducing tape hiss. (I bought it because
I have a large library of old, un-noise-reduced, reel-to-reel tapes).
I think the circuit works pretty well. I am not impressed with Radio
Shack's implementation (using the National Semiconductor chip), because
this circuit also adds noise to the system. It has a noise that sounds
similar to tape hiss, although not as loud.
Raan Young
(hp-pcd!raan)herbie@watdcsu.UUCP (Herb Chong [DCS]) (04/08/85)
In article <5200007@hpcvry.UUCP> raan@hp-pcd.UUCP (raan) writes: >I thought I would share some experiences with various audio accessories >and gadgets. > >Tiptoes -- from Mod Squad > <...> > These cones are extremely unstable unless properly installed. If the > speakers are heavy, this will take at least two and maybe three people. > One to lift the speaker and one (or two) to position the cones under > it. I found that the surface the flat side of the cone is placed against > must be FLAT and parallel to the floor. If your speaker has feet on it > that are not at least as wide as the flat end of the cone, you will have > to remove the feet. After experimenting with various feet (ranging from > 1/4" thick 3/4" round rubber screw mounted to 1/16" thick stick-on rubber) > I found that the best results were obtained with no feet at all. To > obtain better coupling between the speaker and cones (and aid in their > installation) I put a layer of double stick carpet tape on the surface > of the cone (this is a thin solid [not foam] plastic tape). there are tiptoes clones that have a screw coming up from them. if you are willing to drill a small hole in the bottom of your speakers for each one, then these are probably better at coupling the speaker to the floor. also, use 3 instead of 4 because the speakers then rest on a tripod and will not rock even if the floor is uneven. if you have to drill holes all the way through, remember to put a dab of silicone or other caulking compound which is removable to seal the hole and guarantee that it's airtight (not that the leakage is significant. i have not experimented with mine yet because i have to do more things to my speakers first. >Omega One anti-static mat -- from Sound Saver > > This is a stiff 1/16" thick carbon fiber mat that fits snugly around the > center post over the turntable mat. > > It is supposed to drain away static charge on the record. I found that > it does work. It has no discernable affect on the sound, and is the > only anti-static item I have found that was really effective. > > One drawback is that it occasionally sheds carbon fibers onto the underside > of the record. These fibers are conductive, so be careful not to get them > into electronic equipment. i personally do not like any kind of fibrous mat because of fibre shedding, and also because of the inadequate damping provided by most (but not all) fibre mats. are you sure that it's really draining the static charges? i have a conductive rubber mat, the Angstrom Ultimat, but my turntable platter and spindle are not grounded, so i realize no benefit against static. however, it provides tight coupling of the record to the mat in conjunction with the supplied lightweight clamp. i was very skeptical when i bought my mat, but since it was on sale and of the type that made more sense physically, i bought it. i used to use an Eon Research Tripad (the guys that make the Tripod, first widely advertised disk clamp) and found that it was no real improvement over my OEM platter mat. using the Angstrom mat made a big difference though. the increased detail in the upper mids was quite noticable, with the resonance of cymbals and other percussion not muffled as before. solo piano was more accurately reproduced with the upper harmonics from the notes being reproduced more properly. plucked instruments like acoustic guitar and harpsichord had a sharper attack and the overtones were more clearly audible. the low end was tighter with a bass drum having depth instead of sounding like a dull thud. next to the bass drum was a snare drum and i could hear the snares vibrating when the bass drum was hit. violin had bite whereas before, it sounded more like a muzak station's violin. other things i was able to hear was the ticking of the watch BEFORE the heartbeat begins on Speak to Me on Dark Side of the Moon. my brother plays drums and my cousin plays and teaches piano so i've had ample opportunity to hear them. also i have friends who play chamber music now and then so i know how a violin should sound. the sheffield drum record was used for these tests, as well as Shure TTR110, Era III, Fresh Aire 4, Finger Paintings UHQR, Dark Side of the Moon UHQR and others. cartridge was a Dynavector DV23R, Fulton Headshell Leads, Technics SH-100 headshell and SL1400Mk2 turntable with modified cables into a modified Yamaha CA-2010 integrated amplifier running 30W/ch pure Class A driving modified and rewired B&W DM7Mk2 speakers and Audio Technica ATH-7 electret condenser headphones. (your mileage may vary 8-)). >Geodisc cartridge installation guide > > This is a plastic, record sized device with markings for setting the > overhang and tracking angle on a cartridge (for tangental tonearms). > > I have no way to double check the alignment of the cartridge as set up > by using this aid, but the result sounds good and it really is easy to use. i have used one before, but i have found that although it gets you close, you have to be very careful about lining up the front of the cartridge with the raised lines on the plastic which are hard to see. a little white paint touched lightly on the raised lines would have made it easier. also, it's hard to see the pivot point of some tonearms, so it's not always easy to use. as with all such alignment devices, they assume that the stylus is properly mounted on the cantilever within the cartridge. this is usually a safe assumption, but if you're very fussy and have a stylus that is very sensistive to alignment (most line-contact types) you will probably want to use this as a starting point for adjustment by ear unless you have access to test records and instruments. with these stylus shapes, amount of antiskating is dependent upon how your cartridge is aligned. i use an ADC Accutrac because i got it long before MFSL made the Geodisc. >Raan Young >(hp-pcd!raan) Herb Chong... I'm user-friendly -- I don't byte, I nybble.... UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!water!watdcsu!herbie CSNET: herbie%watdcsu@waterloo.csnet ARPA: herbie%watdcsu%waterloo.csnet@csnet-relay.arpa NETNORTH, BITNET, EARN: herbie@watdcs, herbie@watdcsu
mat@hou4b.UUCP (Mark Terribile) (04/09/85)
Regarding the Geo-Disc ... I picked up a cartridge and installed it using the
Geo-Disc as a guide. It's not easy, since the markings aren't as sharp as
you'd like them to be. I checked it with the first side fof the Telarc
Omni-Disc: it was withing the precision that the Omni-Disc offers. I brought
it to my hifi dealer a few days later and he checked it with the Dennison (sp?)
gauge. It was within the preision that that device offered as well.
--
from Mole End Mark Terribile
(scrape .. dig ) hou4b!mat
,.. .,, ,,, ..,***_*.