HDTenEightyP/NetNews huggingface dataset:
From: serge@dgbt.doc.ca (Serge Ah Hee)
Subject: Re: Where can I find the Nyquest theorem
Organization: The Communications Research Centre
Date: Wed, 26 Aug 92 16:46:55 GMT

In article <1992Aug25.200552.12909@fcom.cc.utah.edu> dave@news.ccutah.edu (dave martin) writes:
>Where can I find the exact statement of the Nyquest theorem?  I have seen
>some articles attributing certain properties of digital audio to the Nyquest
>theorem which happen to be false.  I am trying to find out if the theorem
>is in error (unlikely) or if the author of the piece I read is wrong (more
>likely).
>
>dave@csulx.weber.edu
>DMARTIN@CC.WEBER.EDU

Any signals and systems textbook should have a chapter on sampling...You can also check out a dsp textbook.

-- 
Serge Ah-Hee                  "Most troubles come from the fact that people 
serge@dgbt.doc.ca		take for granted of what they have, and 
				only care for what they want."
My opinions are mine only.
Newsgroups: rec.audio
From: gekko@sjere.Berkeley.EDU (Atanu Mishra)
Subject:  SONY STRAV970 center channel Que
Keywords: STRAV970, center channel
Reply-To: gekko@sjere.Berkeley.EDU (Atanu Mishra)
Organization: Tandem Computers, Inc.
Date: Thu, 27 Aug 1992 22:52:53 GMT



Hi,
 This question is directed primarily to SONY STRAV970 owners, though
others might also have some useful suggestions!

 The AV970 receiver/amp does not come with a center-channel amp,
unlike it's sister model, the AV1070. I am interested in finding out
about a suitable amp + speaker combination for the center-channel. Not
quite sure about the specs for the channel, but if I am not too off
the mark, the power output is 15W. I currently have Infinity-Ref 3
front speakers. Conventional wisdom has it that ideally one should
have similar speakers for the front and center channels - which
does not sound OK to me, at least in this case!
 Any and all suggestions ( including prices/places etc. ) welcome.

Thanks,
Atanu

 email: mishra_atanu@tandem.com
From: tuohy@dune.Eng.Sun.COM (Willam Tuohy)
Newsgroups: rec.audio
Subject: Re: Tubes
Followup-To: tuohy@eng.sun.com
Date: 28 Aug 1992 21:11:38 GMT
Organization: Sun Microsystems, Mt. View, Ca.
Distribution: usa
NNTP-Posting-Host: dune

In article <collin.714964752@angelo> collin@angelo.amd.com (Collin K. Ong) writes:
>Anybody have ideas as to where I could get large diameter, thick walled
>tubes made or cardboard, wood, etc.?  I would like about 15" diameter.
>I'm thinking of making a sub similar in design to the Hsu Research one.
>Hardware stores?  Construction sites? ???
>Thanks...

Construction supply houses sell stiff-walled tubing in many sizes, 
from about 8" diameter up to several feet in diameter.  Wall thickness
is from 1/4" up, but the tubing is really stiff, don't let the thickness
(thinness) fool you.  It's used for concrete forms for columns on 
overpasses and such.

I got some at Berke Construction Supply in Oakland.
(Maybe it's spelled Birk or Birke or something).  Sonotube is one type,
BekeTube is what it's called at Berke.

>
>collin@brahms.amd.com

Bill
Xref: sparky rec.audio:11972 rec.video:10775
From: henken@ocf.berkeley.edu (Matthew J. Henken)
Newsgroups: rec.audio
Subject: Speaker placement
Date: 28 Aug 1992 21:55:27 GMT
Organization: U. C. Berkeley Open Computing Facility
Distribution: usa
NNTP-Posting-Host: headcrash.berkeley.edu

Hello again!  I've been pestering for quite awhile about equipment
recommendations and opinions.  A great many people responded with information
that allowed me to improve the sound of the system I was going to buy as well
as to save money.  Thanks to all of you.  This is the final system purchase:

NAD 5000 (I was going to get the 5440, which is the same unit without the
	  headphone jack, but with all the raving about the Sony MDR-V6's
	  going on around hear, and since they were on sale for about $60
	  I decided to go for the 5000)

Adcom GFA-555II
Magnepan 2.6/R

Ungrateful wretch that I am, I am back to ask yet more questions of the
proven net.wisdom that resides in this group:  Where do I put the speakers?

The room that the system will be in is 12 by 17 with about 9.5' ceilings
(actually, they could go into another room which is 9 by 13 with 9.5'
ceilings, but it seemed more accoustically "sound" (yeesh) to put them
in the larger room).  I wish I could draw neat ASCII pictures, but I can't.
A bay window takes up almost all of one of the short walls.  A closet
door is in the middle of the other. (This is starting to sound like Zork).
Should I place them along the long or short walls?  Should I love or fear
the bay window?  Any other rules-of-thumb to get me going for a first
placement of the speakers which won't be awful (I realize that regardless of
the general rules I follow, I'll have to play with them to get really the
most from them).  Any help you could provide (again) would be most
appreciated.

Thanks so much,

Matthew J. Henken
henken@ocf.berkeley.edu
From: lstowell@pyrnova.mis.pyramid.com (Lon Stowell)
Newsgroups: rec.audio
Subject: Re: SONY STRAV970 center channel Que
Date: 29 Aug 92 00:29:35 GMT
Reply-To: lstowell@pyrnova.pyramid.com (Lon Stowell)
Organization: Pyramid Technology Corp., Mountain View, CA
Originator: daemon@sword.eng.pyramid.com

In article <1992Aug28.201022.4930@watson.ibm.com> rrogers@watson.ibm.com (Ryan Rogers) writes:
>
>   When looking for a center speaker (which will typically recieve
>signals from a very small range of the frequencies, that of voices),
>you need one which will concentrate on those frequencies. 
    
       If you like soundtrack music, get a center speaker with the
       same range as your main stereo pair.  ANY signal which is
       largely mono (as in a central music instrumental solo) will
       appear in the center channel...and it is NOT band limited.

       Also be very careful that the frequency response is almost
       identical (or better just use 3 alike) to the mains...timbral
       changes as voices move from left or right to center stage can
       ruin the effect.  Or sound effects moving from left to right,
       such as aircraft, etc. etc.   

> Also,
>center channel speakers (if there any good at all) will have a case
>that inhibits magnetic forces from getting in or out.  This is
>due to the fact that a center speaker will most likely be near a
>tv, and you can't have the two components interacting with each
>other.
>
    Most use cancelling magnets inside the speaker cabinet....this
    works.

   One hates to mention the name, but Stereo Review does have a
   current article on surround.  Take it with the usual dose of salt
   but it wouldn't hurt to note that even the "everything sounds
   great" folks now also are convinced that the center speaker is
   just as critical as the left and right.
From: borowski@hpspkla.spk.hp.com (Don T. Borowski)
Newsgroups: rec.audio
Subject: Re: How do I use a "bias fine adjustment?"
Date: 2 Sep 92 18:43:35 GMT
Organization: Hewlett Packard Company, Spokane, Wa.

In rec.audio, mather@sees.bangor.ac.uk (Paul Mather) writes:

>My cassette deck has a "bias fine adjustment" control on it.  I remember
>reading in my instruction booklet what this was and how you used it.
>
>What does this control actually do?  I know it varies the recording
>bias, but since I don't know exactly what role the bias has when
>recording, I'm a little in the dark about why you'd want to adjust it?

It turns out the magnetic tape is in reality very non-linear.  I once had
the bias oscillator quit on a tape recorder of mine.  There was still an
audio signal going to the head however.  Listening to the playback, I had
a hard time even understanding speach!  To make the tape appear linear, a
high frequency signal (bias) is added the the audio signal going to the
head.

>I have a faint recollection that the fine adjustment control is used
>to "tune in" different brands of tape to the cassette deck.  Could
>someone briefly explain why this is necessary?

To high of bias can cause erasure, especially of high frequencies.  Too low
of bias, and you are back to the non-linearity problem again.  The optimum
point seems to be at a level just before the erasure effect begins.  This
level varies with the type of tape (type I, II, IV), and there is even
variation from lot-to-lot of one manufacturer's tape.

>Finally, could someone suggest how I might use my fine bias control
>to "tune in" a tape in practise?  I recently used a That's EM-X tape
>which came out sounding a little bassy when recording with Dolby on.

The usual procedure is to tune your FM tuner to an empty frequency, with
the interstation muting turned off.  The hiss which results contains a good
sampling of all audio frequencies.  You then record this at about -20 on the
record level meters.  Then play back, and compare the sound to the hiss
coming directly from the tuner.  Listen especially to the high frequencies.
Try adjusting the bias to match the sound as closely as possible.

If the Dolby levels are correctly set, it should not matter whether or not
you have the Dolby turned on when you do this.  However, strictly speaking,
you would have to reset the Dolby levels for every tape (or lot of tapes),
just like you have to reset the bias.


Donald Borowski    WA6OMI    Hewlett-Packard, Spokane Division
"Angels are able to fly because they take themselves so lightly."
                                       -G.K. Chesterton
Newsgroups: rec.audio
From: misra@vijay.NoSubdomain.NoDomain (Vijay Kumar Misra x4018)
Subject: Re: Shoppers Advantage on CompuServe
Organization: Intergraph Corporation, Huntsville, AL.
Date: Fri, 4 Sep 1992 20:24:30 GMT

In article <1992Sep3.032951.18753@babbage.ece.uc.edu>, fkrauthe@vlsilab.ece.uc.edu (Frank John Krautheim) writes:
|> Oh no, another is this mail order place any good.
|> 
|> Anyway, has anyone used the shoppers advantage club on Compuserve?
|> They have really good prices (competive with 6th Ave.) on Denon,
|> Pioneer, Hafler, Onkyo, Adcom, etc.  No Yamaha (bummer no DSP-A1000).
|> They have full factory warranty and will extend short warranty's
|> to 2 years.  
|> 
|> I am considering purchasing the new Denon AVC-3030 from them.  This
|> is a nice unit with 110 l/c/r and 35 r, DSP unit, loads of in/outputs,
|> and a exceptional price of $950 including shipping/handling and tax.
|> 
|> Just wondering if anyone has used this and what your experiences were.
|> And all you modemers out there might check it out for great prices and
|> a good warranty.
|> 
|> John
|> 
|> --
|> 			      ______________		   _
|>                               )_____________)     ________/ \________
|>    John Krautheim                       \\       (________   ________)	
|> 				         \\         /   / \_/
|>    fkrauthe@thor.ece.uc.edu               \\_______/  _/ There's no intelligent 
|>    University of Cincinnati		 _/ ..  ...    \  life down here.
|>    Department of Computer Engineering    \_____________/   Beam me up Scotty.



I bought Denon's full set from them and got extremely cheap and many other
things and so far no problem. I bought one microwave from them which had
some problem with it and they just asked me to return it and ups person
came 2 days later and took it away and they asked me to either cancel or
reorder another product. Great place to buy and save money and get satisfaction
as bonus.

Vijay

Newsgroups: rec.audio,aus.hi-fi
From: shiv@bnr.ca (Shiv Naimpally)
Subject: Re: Choosing cassette decks
Keywords: decisions, decisions, *1000
Reply-To: shiv@bnr.ca (Shiv Naimpally)
Organization: Bell-Northern Research Ltd.
Date: Mon, 31 Aug 92 19:24:33 GMT

Technics RS322. 2 dual bays, both bays autoreverse, autoreverse record,
B, C, HX Pro. I've used mine heavily - no problems, dubs music very 
nicely. Very reasonable price. 
Newsgroups: rec.audio
From: shiv@bnr.ca (Shiv Naimpally)
Subject: Re: How do I use a "bias fine adjustment?"
Keywords: cassette decks, gizmos, misplaced instructions.
Reply-To: shiv@bnr.ca (Shiv Naimpally)
Organization: Bell-Northern Research Ltd.
Date: Wed, 26 Aug 92 20:40:10 GMT

The bias fine adjust is used to adjust the recording head's bias current
to suit the particular tape formulation you are using. The best advice
is to stick to one brand of tape so that you don't have screw around with
this. Note that it only affects recording, not playback so you can play
all kinds of tapes without having to make any adjustments.

When a tape is under-biased (ie. insufficient bias) the high frequency
response goes up so the tape will sound bright and you may hear excessive
hiss. When it is underbiased the tape will sound muffled and dull.

I think you can use interstation FM hiss (white noise) to help adjust.
Keep recording and playing back while adjusting the bias until you get
a good match between source and tape. If you're real picky, take it 
to your dealer along with the brand of tape you use and have them
adjust it for you.
From: borowski@hpspkla.spk.hp.com (Don T. Borowski)
Date: Wed, 26 Aug 1992 18:37:24 GMT
Subject: Re: cd player shutdown
Organization: Hewlett Packard Company, Spokane, Wa.
Newsgroups: rec.audio

In rec.audio, bower@pecan.cns.udel.edu (Tyson Bower) writes:

>I quote from page ten of my Pioneer PD-M530 owner's manual.
>
>"Caution:
> Do not unplug the power cord or do not turn off the power with
> an audio timer during playback, as this could result in damage to
> the disc."

Someone at Pioneer ought to be shot!  What about power failures?  
Should I avoid listening to CDs when there are thunderstorms anywhere
within 50 miles (lightning might hit the lines, causing a power drop
out).  Perhaps Pioneer can warn me a minute before some car hits a
utility pole so that I can eject the disc.  What poor design!


Donald Borowski    WA6OMI    Hewlett-Packard, Spokane Division
"Angels are able to fly because they take themselves so lightly."
                                       -G.K. Chesterton

Newsgroups: rec.audio
From: Barry Thomas <thomasb@ucs.indiana.edu>
Subject: Sub woofer kits
Organization: Indiana University
X-Useragent: Nuntius v1.0
Distribution: usa
Date: Tue, 1 Sep 1992 13:26:38 GMT

My son would like to build a sub-woofer from a kit.  He has some
carpenter skills (he didn't get them from me), so I believe he is
interested in building a cabinet and installing the inards.  

I don't normal follow this group so if there is a FAQ list please point
me in that direction.  I would, however, appreicate any advice kits,
sources, prices, etc.  I said I send a note on the net, but I suspect
I'll end up making a donation to the cause.  Money _IS_ and object here!

Thanks in advance
Barry Thomas
thomasb@ucs.indiana.edu
Indiana University

Opinions expressed our my own and do not represent the University
From: prabhu@unix1.cs.umass.edu (rajesh prabhu)
Newsgroups: rec.audio
Subject: (hyper)sensitive CD player
Date: 25 Aug 92 19:54:53 GMT
Reply-To: prabhu@unix1.cs.umass.edu (rajesh prabhu)
Distribution: na
Organization: University of Massachusetts, Amherst

Hi !
     My CD player has developed this problem : It skips when there
is any sudden movement in the room, much like a turntable does -- In most
cases, it jumps exactly one minute forward. It doesn't do it with any
specific CD, and seems to getting more and more frequent - sometimes an
action as simple as a footstep has it skipping.

     Now the question - how do I rectify it ? Is it something as simple
as getting a clean-up kit, or will I need to take it to the dealer for
service -- it's a Sony CDP-190 that I've had for a year and a half, and
it's been used on the average 2-3 hrs a day. It's still within the warranty
period, but the shop that I bought it from isn't (conveniently) near.

     Any help/tips will be appreciated !


Thanks in advance,

-- Raj
------------------------------------------------------------------------

Rajesh Prabhu   prabhu@cs.umass.edu
		
Xref: sparky rec.audio:11881 rec.video:10658
From: jamison@hobbes.Corp.Sun.COM (& Gray)
Newsgroups: rec.audio,rec.video
Subject: Technics SA-GX505 (was Re: A/V Prologic Receivers--FULL SUMMARY!)
Date: 27 Aug 92 19:43:05
Organization: Fun Microsystems, Inc.
NNTP-Posting-Host: hobbes
In-reply-to: mike%jim.uucp@wupost.wustl.edu's message of Tue, 25 Aug 1992 21:34:14 GMT

Thanks, Mike, for a nice summary.  

I guess it's about time for me to post some comments on my
Technics SA-GX505 Audio/Video reciever.  I got mine for
$300 at an inventory clearance sale, and it's performed
pretty well for a few months now (actually, it's cost me
over $1000 more than that, because it got me interested
in home theater and forced me into buying a 27inch Sony
and a Pioneer LD player :-))

Some Basic features of the SA-GX505:
	* Dolby Pro-logic
	* 110 Watts/ch main left & right, 10 Watts center & rear
	* Two video inputs
	* parametric equalizer, with several memories & presets
	* 30 radio presets
	* remote

Things I like:
	* Nice big volume knob, servo-controlled from remote
	* All the volume I need in left & right channels
	* Good surround from Laserdisc.
	* Nicely designed front panel, functionally & aesthetically

Things I don't like:
	* The "universal" remote, while big enough to float
	  Huck and Jim down the Mississippi, only controls other
	  Technics devices (tape, CD, VCR), none of which I possess.
	  Moreover, not all features of the reciever can be controlled
	  from the remote!  The particularly annoying omissions are:
		* Center channel volume!
		* Dolby 3 mode (left, right, center)
		* A way to select "Tuner" without changing the radio
	  	  station (only way to get tuner from remote is to
	 	  pick a preset station).
		* A way to turn tape monitor off (selecting a tape
		  deck function turns on tape monitor, but there's
		  no way to turn off)
	  All the Technics A/V recievers I've examined seem to use
	  the same lame remote, so this is something to watch out for
	  even on the higher-up models.
	* Not enough volume in center channel - 10 Watts just doesn't
	  seem to be enough.  It's possible that my NHT center channel
	  speaker is inefficient, but I don't think that's the problem.
	* Must be on for video to pass through (is this common?)
	* "Mute" is on the remote only, and not on the unit itself.

Though the latter list is much longer than the "like" list, 
I'm actually pretty happy with it, especially given the price
I paid for it.  If I had it to do over again, I would make sure
I got something with better remote control, more center channel
volume, and probably another video input (maybe in front), since
I borrow a camcorder now and then, and might buy one someday.

					-- Jamie

--
Jamie Gray, jamison@Eng.sun.COM        "I am the milkman of human kindness;
Sun Microsystems, Mountain View, CA     I will leave you an extra pint"
From: u9264442@cc.uow.edu.au (Andrew William Easton)
Subject: Recievers with optical digital input?
Organization: University Of Wollongong
Date: Tue, 1 Sep 92 00:20:45 GMT


I am considering buying a Sony CDP-991, which has (as I'm sure the audiophiles
know) an optical digital output. I originally intended to buy a reciever (as
opposed to seperate amp & tuner), something along the lines of the Yamaha
RX-400 (yes, I know this is _very_ old, I haven't looked at recievers lately).
My question is, if I did want to use the optical digital out on my CD player,
is there a reciever with an optical digital in anywhere in this world? If not, 
why not?
My other question is, is there a _noticeable_ difference in sound quality
between using optical digital or analog signal between components, or between
using a reciever or amp/tuner?

Thanx in advance

The Bearded One..... 

------------------------------------------------------------------------------
| u9264442@wampyr.cc.uow.edu.au | "I've had enough of Irish Americans who... |
| 				| talk about the resistance, the revolution  |
| You've all seen a disclaimer  | back home, and the glory of the revolution,|
| before. Mine's the same.      | and the glory of dyin' for the revolution. |
|				| _FUCK_ THE REVOLUTION!!!"  	- Bono       |
------------------------------------------------------------------------------

From: deanc@hpdmd48.boi.hp.com (Dean Cashen)
Date: Wed, 26 Aug 1992 16:26:25 GMT
Subject: Re: (hyper)sensitive CD player
Organization: Hewlett Packard - Boise, ID
Newsgroups: rec.audio

In rec.audio / prabhu@unix1.cs.umass.edu (rajesh prabhu):

>      My CD player has developed this problem : It skips when there
> is any sudden movement in the room . . .

>      Now the question - how do I rectify it ? Is it something as simple
> as getting a clean-up kit . . .
>    . . .   it's a Sony CDP-190 that I've had for a year and a half, and

My CD player does the same thing, and has been getting progressively
worse (although, it doesn't skip by any exact amount, like you said
yours does).  Of course, mine's a Sony too (there was a string not long
about Sony CD players skipping, and I have 5 dead, or dying Sony
products in my home; I haven't had good luck whatsoever with their
equipment).

In the previous strings, which are now passed, someone suggested cleaning
the guides the laser assy rides on, and lubing them.  I tried it without
success.

I'd appreciate any tips too -- replacing broken Sony equipment is
adversely affecting my cash flow!

Dean Cashen
-- Boise

--------<disclaimer>----------
HP and I share some views, but
the ones above are all mine...
From: dplatt@ntg.com (Dave Platt)
Newsgroups: rec.audio
Subject: Re: 1-beam vs 3-beam
Date: 1 Sep 92 18:41:43 GMT
Organization: New Technologies Group, Inc.  Palo Alto CA

>>I had heard that the 3-beam design is cheaper to implement
>>that the one beam.
>   
>   Allegedly true.  And the fact that the number "3" is bigger than
>   a "1" allows marketing literature to convert a vice into a
>   feature.   
>
>   My understanding was that the good 1 beamers required expensive
>   hand alignment of the optics.....and hand labor is notoriously
>   expensive and unreliable.  

I believe that you may have the issues reversed.

To summarize from Ken Pohlmann's book "The Compact Disk":

- Four tracking technologies have been developed: one-beam push-pull,
  one-beam differential phase detection, one-beam high-frequency wobble,
  and three-beam.

- Three focusing technologies have been used: a cylindrical lens using
  astigmatism, a knife-edge using Faucault focusing, and critical-angle
  focusing.  

- Two combinations of these are used in common practice: one-beam
  push-pull with Foucault focusing, and three-beam tracking with
  astigmatic focusing.  Other combinations don't work as well.

- One-beam pickups are usually mounted on a pivoting arm, but can be
  mounted on a linear sled.  Three-beam pickups are always sled-mounted.

- Three-beam-pickup optics are inherently _more_ complex than
  one-beam... they have at least five optical components, where the
  one-beam version has only four.  Three-beam designs require critical
  adjustment of several components;  single-beam designs require only
  one (horizontal placement of the photodiode).  Both designs require
  adjustment of the drive current for the laser diode.

- Three-beam designs are more complex, mechanically - they require a
  sled (two rails) with a linear drive.  One-beam designs can use a
  pivoting arm.

- Neither design has an inherent performance advantage over the other...
  pickup performance must be evaluated on the basis of individual
  players.

So... why are three-beam designs used at all, if they're more complex
and require more critical adjustments?  I'm not certain what the entire
story is... but I've heard that patents and licensing are a real issue.
It may be that it's less expensive (overall) to use a three-beam design,
and adjust it carefully during manufacture, than to license the rights
to use the one-beam design.

-- 
Dave Platt                                                VOICE: (415) 813-8917
              Domain: dplatt@ntg.com      UUCP: ...netcomsv!ntg!dplatt
 USNAIL: New Technologies Group Inc. 2468 Embarcardero Way, Palo Alto CA 94303
Newsgroups: rec.audio