HDTenEightyP/NetNews huggingface dataset:
From: bower@pecan.cns.udel.edu (Tyson Bower)
Subject: Re: Pro-Logic De-Coder
Organization: University of Delaware, Newark
Distribution: na 
Date: Sat, 15 Aug 1992 17:57:06 GMT

Or, if price is a concern, you can find one for as low as $250.

Crutchfield sells the Kenwood SS-992 Dolby Pro-Logic surround processor
for that price.  Includes amps for the center and rear channels (30w and
15w, respectively).  Crutchfield is primarily a mail-order house.

You can call them and request a catalog.  1-800-955-9009
                   ...or place an order.  1-800-955-3000
From: fpf@taurus.gasco.com (Frank Ferguson x3584)
Newsgroups: rec.audio
Subject: Shaking the Room
Date: 18 Aug 92 15:57:26 GMT
Article-I.D.: gasco.1992Aug18.155726.29077
Distribution: na
Organization: NorthWest Natural Gas Company of Portland Oregon


In his posting, Barry Manor of Univ. New South Wales asks advice
on connecting his 12" subwoofer to his hifi amplifier.  I would
avoid this problem by taking a different tack.

Were I you, I'd forget the idea of driving my subwoofer from my
main amp, and biamp instead.  Biamping is far more costly, but it
gets the subwoofing task done properly.  Using the main amp does not.
One of the main advantages of subwoofing is freeing the main amp
from the daunting task of producing those truely energy draining
low frequency notes.  In this way, the main amp can concentrate
on mid and high frequencies, and sound, in process, like a much more
powerful amp than it is.  The bass amp will need to be a powerful one.
I use a Parasound pa260 (60 wpc stereo, 150 watts bridged mono).  This
amp can be "bridged", that is converted into a mono amp wherein each
stereo channel is joined together to produce on higher power, monophonic
channel.  I also use an electronic crossover to split the low and
high frequency signals after the pre-amp and before the power (main
and bass) amps.  This crossover is a car stereo unit, an Alphasonic.
I chose it for its excellent specs and low cost ($100).
By dedicating a separate amp for bass, on can get those truely 
house shaking lows one hears in live rock or amplified jazz performance.
You won't get quite this performance using one amp for both speakers.

If you must use one amp for both, I'd get or build a passive crossover
to use between the power amp outputs and the speakers.  I'd run the
stereo output of the amp into the crossover, connect my high freq.
speakers to the respective outputs and the woofer to the low freq.
output of the crossover.  Since you have two channels, you have the
question of whether you can tie both channels together into the single
woofer.  Some amps will allow paralleling of the channels, that is
strapping the minus from each channel together, and the plus from
each channel together, and attaching the tied pluses and minuses 
to the speaker terminals.  Its hard to know which amps allow this. 
I had the advice on and electrical engineer who had to open the
amp and look at the circuitry to know.  I think that using the
plus from each channel may be safer, however....  Actually, I'd
get the electronic x-over and an additional power amp and biamp.
Try it, you'll like it.

Francis P. Ferguson
fpf@gasco.com
From: dtang@bass.bu.edu (yunfei zhang)
Newsgroups: rec.audio
Subject: Re: Unity Audio range of speakers
Date: 19 Aug 92 05:08:31 GMT
Reply-To: dtang@bass.bu.edu
Followup-To: rec.audio
Organization: Boston University

In article <1992Aug19.022855.16243@newshost.anu.edu.au> bill@phys.anu.edu.au writes:
>Does anybody have any comments to make about the Unity Audio range of speakers,
>particularly the Fountainhead and CAL 1. The Fountainhead is a
>holographic speaker
 ^^^^^^^^^^^^^^^^^^^

Interesting....  I heard of holograms produced by lasers but never
heard about holographic speakers.  Can anyone elaborate on this?
Sounds strange to me....

DMT
Newsgroups: rec.audio
From: freedmanm@woods.ulowell.edu
Subject: SUBWOOFERS How and why?
Organization: University of Lowell
Date: Thu, 13 Aug 1992 20:25:42 GMT

Subwoofers.....

	I have been reading a few post on subwoofers and thought I would put
my two cents in.  First, here is a list of the subs that I have owned over the
past few years....

		Boston Accoustics, SUB SAT six system..
		Phase Technology, PC50
		Yamaha SW100
		Velodyne Servo 1200
		Velodyne ULD 15

I went through a serious upgrading phase, and have learned alot.  So here goes.

The first two are passive subs,  that means the they need to be driven from
your main amp.  You can either go pre-out to pre-ins or speaker outs to the sub
and from the sub to your sattelites.  They both have crossovers and work fairly
well for the money.  But because you are using the power from your main amp,
you are losing alot for you sattelites.

The Yamaha is incredible for being in the 450 price range.  It is front firing,
active servo, small, and very impressive.  Active servo can mean a number of 
things. In this case there is an accelerometer that mesures the movement of 
the driver in the voice coil.  That info is fed back to the amp and the 
compared to the input signal.  If there it doesnt match then there are 
corrections made.  The Yamaha also incorporates a Helmoltz resonator.  That 
is a way or designing a cabinet to more efficiently deal with BASS response.  
If you are limited in dollars, go check this one out.      

Velodyne, in my opinion is the tops.  The servo 1200 has a 12 inch driver and a
build in 100 watt amp.  It is very efficient and very surprising for a 12 inch
driver.  In essence, it buries the SW100.  It is front firing and VERY
accurate.  It has a variable crossover and is very dynamic.

The ULD-15 is by far, the best subwoofer I have ever heard.  And it is well
worth the 1895 that it costs.  It has a 15 inch driver and a separate 400 watt
power amp.  It has no variable crossover so you have to match it with a pair of
speakers, figure out where you want it crossed over and actually change the
resistors in the amp.  As far as acuraccy, if the bass note goes away as quick
as you clap, it does in this sub. And as far as dynamic power, I have given it
everything that My DSP A1000 and CDV 1700 laser disc player has and it just
gets louder.  It is VERY accurate and well, I am speachless...

So, there are a few ideas for subs, if you can afford it, get a Velodyne, if
not go for the Yamaha.  Passive subs kinda defeat the purpose.  By crossing out
the low frequencies with the active subs, you have much more power for your
sattelites.  And stay away from subs that use Active Servo Technology with a
motorized voice coil.  That is where there is a motor instead of a magnet.
They put out an AMAZING amount of bass but the motor really screws things up as
far as sound for everything else.

	Any comments and questions are gladdly accepted...
						Mike.
From: shawn@panix.com (Shawn Herzinger)
Newsgroups: rec.audio
Subject: Sony DTC-87ES Dat rec. vs. DTC-59ES?
Date: 19 Aug 92 21:59:02 GMT
Organization: PANIX Public Access Unix, NYC

Question.

Does anyone have an opinion re: Sony's two DAT recorders?

The '87 has been available for some time now, while the '59 is a new
model.
The '87 is more expensive, has a 4-motor transport, seperate transformers
for analog and digital circuits, and a 4-head system which allows off the
tape monitoring.

The '59 is approx. $150 cheaper, has 3 motors, one transformer, and only 2
heads which will prevent real-time monitoring.  However, the ad-copy states
that Sony has incorporated "third generation DAT technology...You get 
better digital conversion."

Has anyone compared these two decks?  Has anyone read a review comparing 
them?  Input would be appreciated.

Please E-mail to shawn@panix.com
Newsgroups: rec.audio
From: DPierce@world.std.com (Richard d Pierce)
Subject: Re: Adding magnetic shielding to speakers
Keywords: speakers shielding video magnetic
Organization: The World Public Access UNIX, Brookline, MA
Distribution: us
Date: Fri, 14 Aug 1992 01:17:14 GMT

In article <jeberger.8.0@novell.com> jeberger@novell.com (John Berger) writes:
>Is anyone familiar with what materials are available for adding magnetic 
>shielding to an existing set of small speakers?  Obviously, these would be 
>for video use.  Is it feasable to do this after the fact, or are the 
>tolerances so tight that a hobbyist can't do this successfully?
>
>If it can be done, what are the sources for the shielding materials?

Magnetic shielding is not something that can be effectively added to a speaker
by the consumer (Yes, I know, there will be 5 million replies arguing the
point, pointing out this high-mu material or that, which are all very good
at shield AC fields, but not so good at DC fields. Trust me, I do this for
a living!).

The problem arises almost always because of poor tolerances or excessive
magnet material usage (often to compensate for poor mechanical tolerances
in the rest of the magnetic path). Any gap (including the voice coil gap)
that has a property called high magnetic reluctance potentially causes 
excess leakage at that point. The magnetic field will try to find a lower
reluctance path. Often, the stamped steel baskets provide such a path, 
albeit an imperfect one. The result, nonetheless, is that a significant
portion of the field ends up outside the desired magnetic circuit, where
your video monitor or tapes might happen to be in the way.

There are two ways to reduce the external field: the first is to provide
a low-reluctance path for the external field. This you will often see as
a steel cup covering the back of the magnet. While this does help, it often
causes other problems. For example, the steel cup may be so good at its
job that it may, in fact, rob a significant portion of the magnetic flux
from where it is supposed to go, the voice coil gap. The result is reduced
energy in the gap, reduced efficiency and a host of other problems.

The second, and ultimately more effective way, when done right, is through
the use of what's called a "bucking" magnet glued to the rear of the 
speaker magnet itself. It is polarized in the opposite direction and has the
effect of forcing the stray field back in the path its supposed to go. In fact
there might be a net increase in the flux in the gap, raising the efficency
somewhat (and, potentially causing problems the opposite of reducing the
field). The choice of the magnet size and shape is crucial to the success
of the venture, and it's not something that is easily doable (Simply because
most of you don't have access to either the instrumentation needed nor the
range of magnet materials and sizes someone like myself has).



-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |
From: Janne.Anttila@lut.fi (Janne Anttila)
Newsgroups: rec.audio
Subject: Re: Taping from CD question
Date: 19 Aug 92 11:17:41 GMT
	<1992Aug18.190808.21091@walter.bellcore.com> <collin.714189811@angelo>
Organization: Lappeenranta University of Technology, Finland
Disclaimer: Graecum est, non legitur.

In article <collin.714189811@angelo> collin@angelo.amd.com (Collin K. Ong) writes:

   When taping from CD on my Denon DRM-800 three head deck using Dolby C and
   HX Pro, no matter how much I adjust the bias, the tape always sounds 
   brighter.  I have no problem identifying the tape and the CD within one
   switch.

Have you tried different tapes? I've had my DRM-800 adjusted (internal
bias and level settings) for TDK SA-X and telling the difference between 
tape and CD is really difficult.

If you can't find a tape that corrects your problem, then you should
have the deck adjusted for your favourite tape. I'd recommend it anyway: 
it's not expensive and it's the only way to get the most out of your deck 
and the tape. 

--
	Spirits make me move in mysterious ways...
						   Janne Anttila
-- 
	Spirits make me move in mysterious ways...
From: collin@angelo.amd.com (Collin K. Ong)
Newsgroups: rec.audio
Subject: Re: Taping from CD question
Date: 19 Aug 92 02:03:31 GMT
Organization: Advanced Micro Devices, Inc.

fvr@broom.bae.bellcore.com (Frank Ricciardi) writes:

>In article <1992Aug18.140733.1666@ucbeh.san.uc.edu>, vallamn@ucbeh.san.uc.edu writes:
>|> 
>|> Hi !  I have a question about taping from a CD player on to
>|> a Chromium diodide tape.  When I tape from a CD player
>|> ( Sony CDP 241 ) on to a JVC compact integrated stereo
>|> portable ( PC V 88 ) and I find that the tape, which is
>|> a copy, is always a little crisper ( maybe this is a wrong
>|> word ) than the CD itself.  What I mean is, there is more
>|> zing in the tape than in the CD.  Why is this ?  This does 
>   ^^^^

>	I think what you are experienceing is an unnatural accentuation of the 
>high frequency. Probably due to the fact that you are using a high bias 
>tape in normal position. Recording w/Dolby on and playing back with dolby off 
>often has the same result. 

>	PS. No offense, but the portable is probably not the most accurate 
>tape deck in the world.

When taping from CD on my Denon DRM-800 three head deck using Dolby C and
HX Pro, no matter how much I adjust the bias, the tape always sounds 
brighter.  I have no problem identifying the tape and the CD within one
switch.
From: bower@pecan.cns.udel.edu (Tyson Bower)
Newsgroups: rec.audio
Subject: Re: J&R Music World - Thumbs down
Date: 12 Aug 92 02:30:26 GMT
Distribution: na
Organization: University of Delaware, Newark

I had just the opposite happen.  I had called to make a price inquiry.
The operator quickly answered my question and gave me no hassle.  I
haven't ordered from them yet, but I intend to.
From: chris@lightnin.Columbia.NCR.COM
Newsgroups: rec.audio
Subject: Re: Looking for Surround Sound Emulation
Keywords: Stereo, Surround Sound
Date: 19 Aug 92 19:04:53 GMT
Distribution: na
Organization: NCR Corp, E&M-Columbia, Columbia, SC

In article <1992Aug18.000219.1511@udel.edu> bower@pecan.cns.udel.edu (Tyson Bower) writes:
>
>   stuff deleted
>
>True, the first time I saw a magazine article with the design in it,
>I rigged it up.  I found it to be a novelty at best.  Besides, a
>simple Dolby surround processor can be found very cheaply.  Kenwood
>makes a model which comes with its own speakers.  I've seen
>it advertised for $150.  
>
>I feel the advantages of purchasing a "real" surround processors are
>worth it.  The variable delay alone makes it worthwhile.  Not to mention
>the fact that level balancing can be tricky with the homebrew version.
>
>

  I would like to look into this option (buying a seperate processor) 
since I do not have it built into my receiver.  Has anybody out in netland
had any experience with one of these stand alone units that they would like
to share?  I would be interested in finding out where to order one and what
options I should look for.  I do not necessarily need speakers with the 
unit.
   
     Thanks in advance.



-------------------------------------------------------------------------
 Chris Landi                               
 Surface Mount Operations Center                 NCR MCPD -- Columbia
 phone: (803) 739-7364                           Operations & Distribution
   fax: (803) 739-7362                           3325 Platt Springs Road
 email: chris.landi@ColumbiaSC.NCR.COM           West Columbia, SC 29170
-------------------------------------------------------------------------
From: kirk@hpcc01.corp.hp.com (Kirk Lindstrom)
Date: Mon, 17 Aug 1992 05:22:20 GMT
Subject: Re: A/V receiver recs wanted
Organization: Shredding the water of SF Bay, HP-OCD
Newsgroups: rec.audio

forever to fix, yamaha is much quicker... On top of that, Yamaha is so far
ahead of everyone else, (I.E. They co-developed the digital ProLogic Chip with
Dolby, they have the TRUE 70mm surround mode and 50 db channel separation, and
they invented Digital Soundfield Processing) that it will be state of the art
for many years before anyone else catches up.

							Mike.

P.S.  I am biased but I did a lot of research...
----------
I agree.  I just read that a 6 channel chip has been designed and will
show-up in gear next year.  Several movies have been recorded with it.  I
wonder if the DSP A1000 will drop in price once this is out.  BTW, what is
the best price one can get the A1000 for?  (I may get one before the end of
the year).

Kirk out
Newsgroups: rec.audio
Subject: Mini-Disc any specs?
From: greg@ccc.govt.nz (Greg West)
Date: 20 Aug 92 11:37:56 NZDT
Organization: Christchurch City Council, New Zealand.

Hello there

Does anybody have the 'official' technical specs for mini-disc?
Has mini-disc been released on the market anywhere yet?
 
+-----------------------------------------------------------------------+
| Greg West              "Sometimes a cigar is just a cigar"   S. Freud |
+-------------------------> greg@ccc.govt.nz <--------------------------+
From: rossm@orcrist.EBay.Sun.COM (Ross McCammon - SFD Program Management)
Newsgroups: rec.audio
Subject: 4 Sale - Receiver Parts?
Date: 14 Aug 92 17:51:30 GMT
Reply-To: rossm@orcrist.EBay.Sun.COM
Organization: Sun Microsystems, Inc.
NNTP-Posting-Host: orcrist.ebay.sun.com


FOR SALE:

Pioneer Stereo Receiver SX-434

The amplifier works but the tuner doesn't.

$20 or best offer

I work in Milpitas and live in Fremont

=============================================

I also have for sale:


1985 Montgomery Ward's 19" Color TV/Monitor

	* Remote Control
	* Cable Ready
	* Audio and Video I/O

The IC that controls the adjustable functions (sound, channel, on/off, etc.)
is fried. Right now the TV is stuck ON/channel 7. I have schematics and a 
parts list.

$40 or best offer
From: chrisc@gold.gvg.tek.com (Chris Christensen)
Newsgroups: rec.audio
Subject: Re: class D power amp
Date: 12 Aug 92 16:13:50 GMT
Organization: Grass Valley Group, Grass Valley, CA

In article <1992Aug11.230042.394@ccu1.aukuni.ac.nz> stuartw@ccu1.aukuni.ac.nz 
(Stuart Woolford) writes:
>till@acid-rain.lucid.com (Don Tillman) writes:

>>Other problems with Class D are that there is zero power supply noise
>>rejection (before applying feedback) and that the output filter makes
>>feedback more difficult to apply.  

>I intent to use a switchmode power supply, followed by linear regulation, and
>MUCH filtering, probably switching at about 100KHz, would this seem like a
>sensible setup.

One of the things that people usually forget when filtering a
power supply is the posiblity of common mode noise.  I recommend that
in addition to the bipolar filters that you intend to use that you
also do a common mode filter.

The Peavey Decca Series is a commercial incarnation of a class D power
amplifier.  The response spec of the amps indicate -3dB @ 20Khz.

I think that class D power amps are fun to play with and they are
unique but I put my money in the heavy antique design plane old linear
power amp.  Just my opinion, you didn't ask I offered :-)

-- 
Chris Christensen                  The opinions I express are my own,
chrisc@gold.gvg.tek.com            and sometimes they are wrong!
916-478-3419 FAX 916-478-3887      After all, I *AM* only human.
From: CCEB001@UTXVM.CC.UTEXAS.EDU
Newsgroups: rec.audio
Subject: Re: Temperature and component life
Date: 17 Aug 92 16:12:31 GMT
Article-I.D.: UTXVM.168468F96.CCEB001
Organization: The University of Texas at Austin

In article <133141@lll-winken.LLNL.GOV> turner@rastaman.llnl.gov (David Turner)  writes:
>My new amp lives on the top shelf of my stereo cabinet, which is an old wooden
>armoire.  I noticed that it was getting quite warm up there, so I rigged up a
>hanging thermometer above the amp.  On a hot day, with loud music playing, I
>saw temperatures above 100 degrees F., actually around 110.  I know this is
>warmer than I would like, and I plan on adding a fan and more vents to the
>cabinet.  But it made me wonder:  How warm is too warm?  How much damage am I
>doing to my amp by having it bathed in 110 ambient degrees?  I would be inter-
>ested in seeing a discussion of heat and its effects on stereo components.
 
I have a similar setup in my home.  I solved the problem by using separate
preamp and power amps.  The power amp lives on top of the amoire hidden by
a bit of crown molding etc.  It gets to sit in nice cool room temp air stirred
up by the a/c and ceiling fan.
 
The preamp only draws about 15 watts and so generates very little heat.  If
you check the ratings on the back, you will find that tuners and cd players
are similar power misers.  Turntables and Casstte decks use more power but
not much more and will be happy enough in a closed amoire, if you do not
try to run them all at once.
 
A power amp, integrated amp, or receiver isout of the question because the
power amp section can get real hot.  All audio components show their power
consumption on the back.  You may assume that all watts eventually become
heat.  You can (I have) even get by with minimalist tube gear such as the
old Dyna preamps.  Just check the power rating before you put it in and do
not feel compelled to run it all at once.  It is really hard to find a
midfi power amp and preamp and it costs more than a receiver but it can
be done.  NAD and and Adcom are good choices for this application.
 
A rig like this definitly increases the spouse acceptance factor which is an
important performance metric.  Most amoires have removable backs which make
installing and removing componenets less painful.  They really cuts down the
dust in your gear too.  An antique pie safe with punched metal sides would
probably stay cool with power amps inside and maintain the saf.  :-)   Amoires
and pie safes large enough for audio components are hard to find.  :-(
 
Mike.Coyne@utxvm.cc.utexas.edu
Newsgroups: rec.audio
From: johnme@ecs.comm.mot.com (John Meyer)
Subject: Re: CD noise problem?
Organization: pcb_design
Date: Wed, 12 Aug 1992 12:52:40 GMT

      every now and then my audio system spits out a 1 second burst of noise and
distortion while playing music.this has happened while using the 'cd' player.i'm
doing more testing in other modes to see if its the amp.is this a typical problem
when a cd player is failing? cd player is a Yamaha.



                                                   thanks in advance
                                                        john m.
Newsgroups: rec.audio
From: finnegan@invader.navo.navy.mil (Kenneth Finnegan)
Subject: DAK BSR Compact CD Player
Nntp-Posting-Host-[nntpd-29538]: invader.navo.navy.mil
Reply-To: finnegan@navo.navy.mil
Organization: Grumman Data Systems	
Date: Thu, 13 Aug 1992 17:23:22 GMT

I was recently given a BSR Compact CD player from DAK.  (The
little one that's slightly larger than a CD).
The unit seems quite nice, and according to the catalog it was
purchased from, costs only $89, including the case, headphones
(earphones, actually), AC adaptor, and component patchcord.  Has
anyone had any experience with one of these units?  (No DAK-bashing,
please, I've had good experience with their products and service.) 

My only complaint so far is that the little ear-phones are 
uncomfortable.  Any opinions?

Thanks,

Kenneth
finnegan@navo.navy.mil

"Bang-a-rang!"
From: lionel@cs.city.ac.uk (Lionel Tun)
Newsgroups: rec.audio
Subject: Re: Why does spiking and Blu-Tak work?
Date: 14 Aug 92 12:38:41 GMT
Organization: City University, London

iscstk@nuscc.nus.sg (Siew Teng Kean) writes:
>So the purpose
>of spiking is to isolate, not to couple?

From my position of armchair theory, I gather that either can
apply. If the floor is solid concrete then you want to couple
to that floor with bolts or spikes. But if it is an upstairs
flimsy wooden floor, then you want to isolate from that floor
and instead get inertia from massive stands etc (or hang by
piece of string from the ceiling?).

--
Lionel Tun   (lionel@cs.city.ac.uk)
Vision Group, City University, London, EC1V 0HB. 071-477 8000 x 3889