HDTenEightyP/NetNews huggingface dataset:
From: grego@bit.UUCP (Greg Sanguinetti)
Newsgroups: rec.audio
Subject: Re: Subwoofer amplification
Date: 22 Dec 92 19:37:26 GMT
Article-I.D.: bit.543
Reply-To: grego@bit.UUCP (Grego Sanguinetti)
Organization: BIT  Portland, OR

In article <1992Dec22.005805.20878@organpipe.uug.arizona.edu> tom@afthree.as.arizona.edu (Thomas J. Trebisky) writes:
>In article <1992Dec21.125142.1@tnclus.tele.nokia.fi> lauusitalo@tnclus.tele.nokia.fi writes:
>>In article <1992Dec21.111548.1@tnclus.tele.nokia.fi>, lauusitalo@tnclus.tele.nokia.fi writes:
>>> And as said before that supply needs reconsideration. For full swing
>>> you need about +-24V supply with enough current capacity.
>
>This is probably obvious to many, but when building a power amp and
>designing the power supply, there is an intimate relationship between
>the voltage levels and the current it can deliver into the load.
>
>For example (as a first cut, just think DC and view the speaker as a
>resistive load).  Put 12V across 8 ohms and the max current flow is
>12/8 = 1.5A.  It doesn`t matter if the supply can deliver 100A, only
>1.5A is going to flow into that load no matter what you do given 12V.
>So, you need to scale up the supply voltages.  Get a split +-36 volt

Woops! I thought this thread was about using a car amp to drive a subwoofer?
My mistake I guess. My last post was based on that assumption.

In a car amp is a switching DC-DC converter that takes the 12 (actually 14)
volts from the car and converts it to the necessary internal rails to drive
the amp. It is expecting a single ended ~12v supply and shouldn't be supplied
with more than about 18volts without fear of overloading the input. It
depends on how robust the converter is.

Now if your building an amp and power supply then yes, a 120w amp typically
uses a 40 to 50volt bipolar supply with a minimum of 3A rating.

-grego
-- 
---------------------------------------------------------------------------
Grego Sanguinetti, Bipolar Integrated Technology | Water, water everywhere,
grego@bit.uucp or grego%bit%ogi.cse.edu          | but I'd rather drink
or bit!grego@ogi.cse.edu or ...!ogicse!bit!grego | beer.
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: rec.audio
Subject: Re: ARE 100-110 MINUTE TAPES BAD?
Date: 2 Jan 93 02:14:11 GMT
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA

In article <1992Dec30.071318.8763@mel.dit.csiro.au> gre253@mis.csiro.au (Steven Green (+61 6 276 6813)) writes:
> In article <1992Dec20.001558.7861@iitmax.iit.edu> tranhun1@elof.iit.edu (Hung Q. Tran) writes:
> >
> >I always see the 100-110 minute tapes usually cheaper than the 90 
> >minute tapes.   Are they necessarily delicate?  What difference
> >is there between the quality of a 90 min tape and a 100 min tape.
> >
> >thanks tran

> I've been using TDK MA-110's for a little while now. My impressions to date
> have been _very_ good. They reproduce brilliantly and seem fairly robust.
> I've used quite a few in my car and the handly the wear-and-tear of that
> environment without any problems.

On the other hand, I've had problems with the MA-110's in both car
and my old Kenwood deck at work.  I'd guess it's basically a question
of how good of shape your decks are in.  If you get a clean wind on
the cartridge and the deck is running good, with no slippery old
belts then you should have no problems.  If the tape doesn't wind up
smoothly or the deck doesn't have enough clean torque, you may hear
that draggy action or extra wow/flutter towards the end of the tapes.

Expecially with auto tape players and portables, the safest bet is
still using 60-70-90 minute tapes.  If you want to use longer tapes,
get a few and beat on them for a week or two.  You may find that
they work nice the first couple times and then go downhill as the
tape winds less cleanly and drags more...

As far as quality, the old story was that most > 90 minute tapes
were only available in TYPE I (standard oxide), but with the CD era
you can get high-bias and metal tapes in extended length.  They
still have to use a thinner base, so in addition to the mechanical
issues, there may still be an issue with print-thru.

-- 
George Robbins - now working for,     work:   to be avoided at all costs...
but no way officially representing:   uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
Commodore, Engineering Department     domain: grr@cbmvax.commodore.com
From: sudesh@utkal.njit.edu (T. J. Sudesh)
Newsgroups: rec.audio
Subject: Opinions on PIONEER (A-757) Reference stereo amp......
Date: 22 Dec 92 17:15:20 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.


 Hi,
    Just yesterday I had requested opinions on the pioneer amp(A-757) which is
150W + 150W/4 & 100wpc/8-ohm reference amp.I also purchased the SONY CDP-297
.But to my dismay the system sounds "VERY DUSTY".I also bought JENSEN 3013
3-WAY speakers & an ONKYO AM/FM TUNER.All in all I busted $1200 on this, but the
sound quality seems to be very poor.Could someone out there please guide to the
"blachsheep" of the components, I have purchased ?? Its over a week ago that I 
bought the AMP & TUNER from NBTW.Could I try returning the same now, if the amp 
is the culprit.I'm kinda confused........Please advise.......

Thankx in advance for any help.....

warm regards,
sudesh.
From: cal@gsbux1.uchicago.edu (Cal Lott)
Newsgroups: rec.audio
Subject: Re: is pre-amp necessary for line-level input?
Date: 31 Dec 92 01:43:20 GMT
Organization: University of Chicago Computing Organizations

Youngjoon Kwon     (415)926-2761 <YKWON@SLACVM.SLAC.STANFORD.EDU> writes:

>If I don't use a phono input, is separate preamp necessary for
>line level inputs such as CD, D/A, or tape? (Of course, except for the
>control functions.)
>
>To be more specific, I am thinking of purchasing an Acurus amplifier
>and I have two choices:
>One is more conventional - get a pure power amp, such as A250 and a
>separate line preamp, L10.
>The other is to purchase a "direct-input-amp" DIA-100, which contains
>passive control sections including source-switching and input attenuation.
>
>For now, I don't think I would ever need a 250w/ch capability of A250.
>The only concern I have is whether a separate line-level preamp gives
>any long-term benefit to the system.  (For a short term, I don't think
>I can easily hear a sonic difference between the A250/L10 and DIA-100.)

	The short term may be fine, but I have a couple of more long-
term items that you may want to consider:

	-1) How will that delicate preamp stage fare over the next few
	    years after it spends a great deal of time next to that
            hot, noisy amplifier stage?

	-2) Another benefit of seperate components in addition to
	    higher fidelity (which you mentioned is not a problem for
	    you in this case) is greater flexibility. If you should
	    want to upgrade/change your amp or preamp, you will not
	    be forced to throw one component out with the other.

>I would appreciate any help from the net fellows. (either technical or just
>subjective)
>                                      -Youngjoon

	I am not terribly worried about #1, since Acurus is a fine
line of components. I would carefully consider the flexibility 
issue, however.

	Best of luck in putting together your system.

					-Cal
--
----------------------------------------------------------------------
Cal Lott          "Oh, I see-- I thought 'no' meant 'spoon'!" --Dan
Email me, baby!   cal@gsbux1.uchicago.edu   cjl1@midway.uchicago.edu
----------------------------------------------------------------------
From: shetline@bbn.com (Kerry Shetline)
Newsgroups: rec.audio
Subject: MD and DCC encoding-request for info
Followup-To: rec.audio
Date: 28 Dec 1992 02:52:19 GMT
Organization: BBN
Distribution: world
NNTP-Posting-Host: bbn.com

Does anyone know where or how I could get hold of the standards for MD's
ATRAC encoding and DCC's PASC encoding? I'm just curious to know what
*really* happens to the digital audio data. It's one thing to say that
"sounds that can't be heard (at all/ unless you try real hard/unless you
try/unless you're not tone deaf...)" are thrown out. It's another to say
what happens to the data stream. After all, you certainly can't toss out
PCM data points and get anything useful. My guess (putting bits and pieces
of what I've heard together with some things that I've learned about
voice-specific audio compression) is that the spectral analysis is used to
figure out the trade-offs to be made in some sort of approximating waveform
parameter list -- such as a polynomial or wavelet equation. That is, an
aproximating waveform is choosen that differs from the original waveform
only in content that falls below the calculated psycho-acoustic thresholds.
Am I in the ballpark? (I realize the answers might be different for MD or
DCC.)

Also, I'm wondering about the digital I/O on these new machines. Do they
always process PCM data, or can the actual compressed data be transferred
from one unit to another? (Again, I realize the answers might be different
for MD or DCC.) If they only handle PCM data, would there be a generational
degradation when copying MDs/DCCs (forgetting about serial copy mgt for the
moment)? It seems to me quite likely that there could be -- calculation
round-offs, inconsistent "framing" of the PCM data stream, etc. What I am
asking is,

   if X is a compressed data set
   and DECOMP() is a function that expands compressed data into PCM
   and COMP() is a function that compresses PCM data

is COMP(DECOMP(X)) = X guaranteed?

(It is of course obvious that for a PCM data set Y that DECOMP(COMP(Y))
will rarely equal Y>)

-Kerry


-Kerry
From: twong@civil.ubc.ca (Thomas Wong)
Newsgroups: rec.audio
Subject: Comments on Nakamichi's last year models....
Date: 24 Dec 1992 03:42:27 GMT
Organization: Dept. of Civil Engineering, U.B.C., Vancouver, B.C., Canada
Distribution: world
NNTP-Posting-Host: sam.civil.ubc.ca

Hi everyone. I have been given an opportunity to buy a Nakamichi
Receiver 2 and a Nak Cassette Deck 1.5 which was last years model hence
they can give it to me for almost 40% off. It's a real steal but my
problem is that the other components I want to get (speakers, cd player)
is in other stores hence I can't really do a real comparison until I bring
everything home and hook it up (the other 2 are still undecided yet). So
I was wondering what other people's opinion on these 2 components are.

These will be SALE items so I can't bring them back. That's my problem.
They sound good in their soundroom hooked up to speakers around my price
range but not quality I don't think. So I can't eally compare it with
what I want to buy. So I had them hooked up to something way out of my
price range ($2000 Mirages) and it sounded REAL good. But I was only
going to spend a couple of hunred on my speakers and they probably
won't be of the same quality. Or at least not of the quality of the ones
I've been testing. So I don't know if it's the speaker or the
components. 

Any Nak owners out there? For about the same price, at another store, I
can go with NAD 705 receiver which also sounded real good. But can't
compare them cause different soundroom, speakers, everything was
different. I was also listening to the a Luxman and Denon of the same
price range but weren't as good. Are Naks one level above that of NAD,
Denon, Luxman...etc?

Thanks in advance. I need to know before the end of this week.
But the sooner the less chance of it being sold! :)
Thanks again!

Thomas.


Newsgroups: rec.audio
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: CD Sound Quality
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Sat, 26 Dec 1992 07:22:21 GMT

myers@hpfcso.FC.HP.COM (Bob Myers) writes:
: > Say you sample at 44 KHz.  The maximum theoretical limit of frequency
: > you can capture is half of this, 22 KHz.  However, at this rate there
: > are only two samples per cycle.  With two samples per cycle, a sine
: > wave will sound the same as a square wave.  Surely this is not hi-fi?
: > Suppose you say that you cannot hear this high a frequency.
: > Well, at 11 KHz, there will be 4 samples per waveform.  How close
: > to a pure sine wave can you get with 4 samples?  By looking at it,
: > not very.  I'm not sure how noticable the difference in the sound is.
: > I guess it wouldn't be difficult for someone with a computer with
: > reasonable sound capabilities to try this out.
: 
: God, not this again.  Here, let me introduce you to my good friend, 
: Mr. Fourier, and his friends, Mr. Shannon and Mr. Nyquist.....

He probably believes that the lathe cutter cuts a square wave into 
the vinyl on the analog disc.

Bill
From: co940@cleveland.Freenet.Edu (Nicholas E. Damato)
Newsgroups: rec.audio
Subject: Re: Analog CDs (was: CD Sound Quality)
Date: 27 Dec 1992 05:22:31 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: hela.ins.cwru.edu


I believe that the favorite piece of music that determined the
length of the CD was Beethovens 9th Symphony. I think it was
incredibly short sighted. you could easily have made a 2hr format
at not much of an increase in cost. (Imagine what CD rom could
hold if such were true...)
or in size.
 
I've been following the thread on CD vs. Analog Quality.
My post a few messages back generated a few good flames
via E-mail. I would now like to propose the following hypothesis.
 
Hypothesis:
My friend has a very expensive turntable set-up. over $2200.
He has some fairly recent audiophile pressings, and I have
been listening to them. (mostly ANALOG masters of course...)
THis guy is a die-hard Analog freak, and after listening to
some of his discs, i have to say he has a point. outside of
Dynamic range, and a little surface noise, There definitely
seems to be some sort of "fullness" to the music that simply
isn't present on CDs. My proposition is this: First let me say
that I'm not all that familiar with digital recording technique,
dithering, and all that business. I know that in the synthesiszer
world, the more bits you get (8-16-32) in the sampling, the 
better it sounds. 
 
In CD recording, it is designed to utilize all the bits in a flat
and equal manner across the bandwith of the freq. response.
now, our ears are not "flat" by any means. They are much more
sensitive both to frequency and dynamic changes in the areas
where speech occurs, and in a "head and sholders curve" around
that midpoint. Maybe if Digital recording were modified to      
increase precision in a manner following the response curves of
our ears (i DONT mean boosting the midrange, i mean using more
bits over those frequencied in more precision, the volume would       
remain unchanged) Perhaps we could unluck the analog "missing
link" here.
 
For those rude folks who flamed my opinion that the ear is the
most sensitive dynamic instrument created, I would like to say
that i can't name any microphones with a 120+ Db Dynamic range
at near zero distortion, (notto say the don't exist, I've just
never encountered any...)
 
Anyone agree? disagree? (let's keep things polite here, this
is just a discussion...)
 
ned.
Xref: sparky rec.audio:17426 rec.audio.pro:2652
From: brian@uoft02.utoledo.edu
Newsgroups: rec.audio,rec.audio.pro
Subject: looking for altec 811 horns
Date: 28 Dec 92 17:34:34 EST
Organization: University of Toledo, Computer Services



Hello,

I'm looking to purchase a pair of used Altec H 811B midrange horns. If
anyone is willing to part with a pair, please let me know. I do have the
drivers. I will consider equivalent horns, if so, please describe the horn
size and throat size at the coupling to the driver, and mounting, it would
have to be a flange mount.

brian nelson
sr. systems programmer
university of toledo
brian@uoft02.utoledo.edu
(419) 537-2841
Newsgroups: rec.audio
Newsgroups: rec.audio

I'm happy with my Mirage center channel speaker and it fits your budget.

Kirk out
From: Guha@mcc.com (R. V. Guha)
Newsgroups: rec.audio
Subject: B&W 804s for sale
Date: 30 Dec 1992 10:40:29 -0600
Organization: UTexas Mail-to-News Gateway
NNTP-Posting-Host: cs.utexas.edu



Black B&W 804s, with Sound
Anchor Stands and High pass
allignment filter. Everything
in perfect condition. Streophile
class C (borderline class B). 
List price for the whole 
thing - $2600.

Asking for $1250.

Send me mail at guha@mcc.com.

Guha
From: slin@cisco.com (Steven Lin)
Newsgroups: rec.audio
Subject: Re: CD Changers
Date: 29 Dec 92 10:50:14
Organization: cisco Systems, Inc.
NNTP-Posting-Host: regal.cisco.com
In-reply-to: AOAFF@ASUACAD.BITNET's message of 28 Dec 92 20:49:46 GMT


   From:    AOAFF@ASUACAD.BITNET
   Newsgroups: rec.audio
   Date:    28 Dec 92 20:49:46 GMT

   In article <SLIN.92Dec23140812@regal.cisco.com>, slin@cisco.com (Steven Lin)
   says:
   >
   >This may not be important to many people, but 6-CD magazines are
   >standarized, so if you have several CD players (say, one in your car
   >and one at home), you can quickly move the magazine from one CD player
   >to another.

   standardized? There are at least two types of 6 disk magazines: the
   Pioneer, where the trays swing out in a semi-circle; and the Kenwood/
   JVC type where the trays slide straight out and back.

   Allen

I stand corrected.  I have never seen the Kenwood/JVC type so I don't
know how popular they are, but the so-called Pioneer type cartridge
seems to be popular.  Denon and Pioneer both make CD players that can
accept Pioneer type cartridges.  You can identify these cartridges by
an emblem consisting of six overlapping rings.

Steve
From: jeh@cmkrnl.com
Newsgroups: rec.audio
Subject: Re: questions on new digital formats
Date: 30 Dec 92 04:41:02 GMT
Organization: Kernel Mode Consulting, San Diego, CA

In article <C01pCJ.GLp@cs.columbia.edu>, ethan@cs.columbia.edu (Ethan Solomita) writes:
> In article <1992Dec29.204744.7518@adobe.com> caro@adobe.com writes:
>>
>>Against all this is the common sense guess that the recording industry
>>will tolerate only *one* consumer recordable medium for new releases, as
>>we have seen with the film industry.  To my surprise, there seems to be
>>just as much support for MD as there is for DCC at the moment, but I
>>wonder how long that will last?  Is this Beta all over again?

As I've mentioned elsewhere, maybe not -- it might be 8mm all over again. (8mm
has pretty much won the camcorder market.) 

> 	One thing to note: Sony IS part of the recording
> industry. And they developed the second standard. Now, perhaps
> their two divisions are separate (they should talk to Microsoft
> about this 8), but I expect they planned this.
> 	-- Ethan

But Phillips is part of the recording industry too, or so I thought.  Don't
they own Polygram ?

	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
Uucp:  ...{crash,eisner,uunet}!cmkrnl!jeh
Newsgroups: rec.audio
From: Jonas.Palm@orgk3.lu.se (Jonas Palm)
Subject: Re: CD SOund QUality
Followup-To: rec.audio
Organization: University of Lund, Sweden
Date: Tue, 22 Dec 1992 19:51:17 GMT

In article <24463@alice.att.com>, jj@alice.att.com (jj, curmudgeon and
all-around grouch) wrote:
> 
> In article <1992Dec21.213820.2737@cbnewsh.cb.att.com> ledzep@cbnewsh.cb.att.com (carl.w.muhlhausen) writes:
> >jj,
> >
> >I (and I think other rec.audio crazies) would be interested in what
> >audible improvements we'd get out of more dynamic range and a
> >higher sampling rate. I was under the impression that 16 bits
> >gives more dynamic range than we need and a higher sampling rate
> >would benefit dogs and bats but few humans.
> 
> Well, I'm not sure I'd say that one would get ANY benefit out
> of more that 16 bits in a PROPERLY RECORDED CD.  Now, having
> said that, my experience is that a lot of the CD's I own (I
> do Audio signal processing for a living) are simply
> not recorded decently.  <This from looking at spectra, levels
> and such taken DIGITALLY from the CD>  So, I think that
> 18 bits might help the poor recording engineer.

..goes on to discuss sampling rates...

Could you please make the above statement absolutely clear.
Do you mean that the recording engineer should have (say)
18 bits at his disposal, for instance in order to be able to 
maintain a reasonable safety margin when recording, but that
16 bits should then be sufficient in the actual CD-medium?

The recent article in the JAES some months ago about noise
in the recording-playback chain would seem to imply this, but
you may not agree.

                                       Jonas Palm
From: jj@alice.att.com (jj, curmudgeon and all-around grouch)
Newsgroups: rec.audio
Subject: Re: MiniDisc is here!
Date: 27 Dec 92 03:55:22 GMT
Article-I.D.: alice.24487
Reply-To: jj@alice.UUCP (jj, curmudgeon and all-around grouch)
Organization: NJ State Home for Bewildered Terminals

In article <Bzu539.DDt@news.cso.uiuc.edu> rmg53668@dcl-nxt53 (Ryan Martin Grant) writes:

>Assuming of course that the PASC circuts are dropped for computer srorage, and
>that the important part of the MD is the MO read/write features, they seem

What, pray tell, PASC circuit in the MD?  PASC is used in DCC.
"ATRAC", which is a transform coder, is used in MD, or so
we're told. ATAC, the previous entry involving Sony, was another
of the candidates at the ISO contest where ASPEC won the quality
contest.
-- 
Extremism *Copyright alice!jj 1992, all rights reserved, except transmission
   in the    *by USENET and like facilities granted.      Said permission is
  defense of     *granted only for complete copies that include this notice.
 liberty is no vice.  *Use on pay-for-read services specifically disallowed.
From: mbodas@natukawa.intel.com (Milind Bodas)
Newsgroups: rec.audio
Subject: FAQ?
Keywords: FAQ
Date: 1 Jan 93 00:08:01 GMT
Followup-To: poster
Distribution: usa
Organization: Intel Corporation, Santa Clara, CA

Is there an FAQ for this news group? If so could someone
mail me a copy.

Thanks,

-- Milind
mbodas@mipos2.intel.com
From: chrisc@gold.gvg.tek.com (Chris Christensen)
Newsgroups: rec.audio
Subject: Re: Question about rear speakers for surround sound
Date: 21 Dec 92 17:43:30 GMT
Organization: Grass Valley Group, Grass Valley, CA

In article <28780@oasys.dt.navy.mil> lkelly@oasys.dt.navy.mil
(Lawrence Kelly) writes:

(TEXT EDITED)

>I was talking to
>a salesman who said that it used to be good to get small low watts-per-
>channel rated bookshelf speakers, but now more manufacturer's are
>pushing the rear speakers harder.  I believe that the KRV-7030 outputs
>15 WPC for rear.  Does anyone have any speaker recommendations?  Is
>the salesman correct?   I have been told to look at low end models

The salespersons agenda: Bigger speaker=higher sales commission......... 

I have heard people say that certain modes of "Dolby ProLogic" do
exercise the rear speakers more but I don't believe it, 'specially if
they are listening to a theatrical release.  The people mixing these
movies know well how to fool the audience.  If you hear a rumbling
flyover of a jet or a space ship the LF is coming from the front
speakers.

I have tested the listenability of surround channels that have lots a
low end.  I find it distracting.  My tests and examination of this
affect was based on the Sound Designer portion of my life/business.  I
present it as a professional opinion.

The surround channel is an effects channel.

If you challenge my assumption connect the surround channel to one of
your main speakers and listen to it.  I believe that you will find
that the suround channel is band limited,  if not, I want to know the
movie you used so I can test it for myself!

I have said it before and I will say it now,  the selection criteria
for the surround speakers is: smooth amplitude and phase response will make
the surround "sound" at it's best! 
-- 
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: allana@hpmwtd.sr.hp.com (Allan Armstrong)
Date: Wed, 23 Dec 1992 19:18:33 GMT
Subject: Re: Carver and the FAQ
Organization: HP Santa Rosa Site (SRSD MWTD)