HDTenEightyP/NetNews huggingface dataset:
From: Dave Dal Farra <gpz750@bnr.ca>
Subject: Re: Wanted to know bi-amp speakers advantages
X-Xxdate: Wed, 6 Jan 93 18:54:40 GMT
Organization: BNR Ltd.
X-Useragent: Nuntius v1.1.1d9
Date: Wed, 6 Jan 1993 18:46:19 GMT


Dick Peirce states in his "BUNK ALERT" piece
that passive loudspeaker crossovers do not disipate power.  

Wow.  I think Dick was going a little overboard and was
not really on the money.

Nearly every truly decent crossover I've ever built or seen
built dissipates some power for reasons other than the 
standard high pass or low pass functions.

Why?  

To correct for a woofer and/or mid and/or tweeter's non-
ideal frequency response:

i.e. to smooth out its response by removing broad humps 
     over certain frequency ranges.  Most woofers I've seen
     need some sort of correction in this manner, wether it 
     is acccomplished via altered filter slopes or by low-Q
     selective notches.
     
Some cases will exist where this is not necessary as the 
drivers will already be flat enough.  These cases are rare.
 
In these cases, the extra loss due to crossover resistance
will be negligible and on the order of 0.5 dB.

But Mark's post was not "BUNK" as the majority of properly
designed crossovers implement frequency response tailoring
and hence dispate power.

An active crossover showing the correct frequency tailoring
will result in a power savings and a resultant increase in 
headroom.

A system I am currently designing utilizes active x-overs
as the woofer (a VERY well-regarded unit) needs up to 6 dB
response correction broadly centered around 1 kHz.

The active crossover effectively QUADRUPLES my "effective"
available amplifier power at these frequencies.


....Dave
From: wsun@jeeves.ucsd.edu (Fiberman)
Newsgroups: rec.audio
Subject: speakers for classical music
Date: 10 Jan 93 22:30:04 GMT
Organization: University of California, San Diego

For all the experts out there:

If money were no object, what speakers are the best for
listening to classical music?

-fm

Newsgroups: rec.audio
From: schippit@seviche.ycc.yale.edu (Mark G. Schippits)
Subject: Re: Bose Speakers
Followup-To: rec.audio
Organization: Yale Medical Informatics
Date: Fri, 8 Jan 1993 13:43:09 GMT

Series V & VI use the same drivers but have different cabinets.  They are
compatable with the same EQ as well.  Both are premium Bose speakers. 
Comparing them to the AM or SE satelite series is like comparing a Mercedes
to a Mercury Lynx.  Ether is is quite adequate and will do the job it just
depends how luxurious a sound quality you seek & how much volume you like
to hear (like how fast you like to drive on the highway!).  The Bose 901's
are quite nice for a dorm.  I have seen them hung from the ceiling to
conserve space.  I own a set of series V 901's and am quite happy for them.
 I doubt I would feel similarly about any earlier version however.  Series
V & VI are state of the art!  The drawback to Bose in all truthfulness is a
lack of "powerfull, deep" bass.  Oh yes, they have power alright.  Sales
reps plug these speakers directly into house current and the speakers are
just as good as they did before the abuse.  No other speaker owner or
manufacture would likely try this one.  Also they have deep base,  HI-Fi
mag vol 86 says to 28hz (-3db).  But the little 4.5" drivers begin to sound
airy and fall apart (bottojm out, distort) at louder volumes of deep bass. 
The sol'n, ideally, a 12 or 15" Velodyne sub-woofer!!  Of course I'm quite
sure the same could be said of the AM5 and most other speakers as small as
the Bose on the market.  The miricle of Bose engineering is not the sound
quality, other manufactures have that down better, but rather squeezing
something close to that quality from such a small box!! Feel free to
contact me if you have more questions re the 901's.  Also I know someone
selling a pair of series V's for $750 but I cannot vouche for their
condition since I have not seen them.


In article <1993Jan7.201647.4897@athena.mit.edu>, dondon@athena.mit.edu
(The Don) wrote:
> 
> Hello, out there!  I am new to this group but I am wondering if you could offer
> some advice to a novice to the world of audio.
> 
> I have a few questions here.  First, I am trying to decide whether to buy the
> Bose AM-VIIs or the 901s.  I will be living in a dorm for the next three years,
> probably and 901s might be overkill.  Also, what are major differences between
> the Bose 901 series IV, V, and VI?  Would a used pair of IV's or V's be a good
> investment?  Finally, can anyone offer advice as to an integrated amp/tuner, or
> preamp-power amp combo for either or both of these speakers?
> 
> Thanks very much in advance.

mark_schippits@qm.ycc.yale.edu
schippit@seviche.ycc.yale.edu
Phone: (203) 785-7443
From: rkeel@fnugget.intel.com (William R Keel)
Newsgroups: rec.audio
Subject: Surround Setup
Date: 4 Jan 93 16:44:49 GMT
Distribution: usa
Organization: INTEL.FOLSOM

I am acquiring an excelent Sony rack system through co-habintation and
I am wondering what the best setup for the surround sound speakers is.
I am assuming that since the surround volume is labeled "Rear", the 
speakers should be placed behind the listening audience.  My question
is, what is the best placement...high, low, pointing at different angles?
How much do accoustics have to do with these speakers?
Another question I have is, will any type of speaker work as surround
speakers?  I have a set of Bose bookshelf speakers that would have a 
richer sound than the small surround speakers that came with the Sony.
Can/should I use these?  And finally...do all surround systems have 
the logic (?) or decoder for accepting surround broadcasts?

Thanx in advance - If y'all mail me the responses, I'll piece together
a post with the responses!

Reed

internet: rkeel@fnugget.intel.com
Newsgroups: rec.audio
From: Mike Ellerson <mellerso@uga.cc.uga.edu>
Subject: FOR SALE - Yamaha DSP 100u system.
X-Xxmessage-Id: <A776EAA361010651@memac.ucns.uga.edu>
X-Xxdate: Mon, 11 Jan 93 09:13:07 GMT
Organization: University of Georgia
X-Useragent: Nuntius v1.1.1d16
Date: Mon, 11 Jan 1993 14:13:07 GMT

Yamaha DSP 100U and Yamaha MX-35 4 channel amp -  This is Yamaha's
digital sound field processor. It has many different digitally stored
soundfield environments with many user adjustable parameters. A really
fascinating piece of equipment. It connects to the tapeouts of your
receiver or between the preamp and amp. It includes a remote control that
will let you control the volume and the various sound field parameters
and will display the settings on a video display. I think this unit was
replaced by the Yamaha DSP 1000. It also includes Dolby Surround and
several movie modes. It requires the use of 2 or 4 additional speakers
for the surround effects. The amplifier can used for four channels at 35
watts/channel or two channels at 70 watts/channel. Paid $900 will sell
for $350.
From: csc@pilot.njin.net (Sean Casey)
Newsgroups: rec.audio
Subject: Any experience with Sony D-515 portable CD player?
Date: 4 Jan 93 19:29:07 GMT
Organization: The Leaning Tower of Patterson Office @ The Univ. of KY

I want to buy a portable that doesn't skip when you breathe on it, and
which has a compression circuit for car use. I've got only a few specs
on the Sony D-515, and I'm wondering if anyone can answer the
following questions:

What is the disk holding mechanism? Some have ball-bearings with
springs that hold the disk in place. In others, the disk just lies on
a platter. The latter doesn't work well in my experience.

Will the memory buffer and the DSP circuit work simultaneously?

Does it come with a car 12 volt adapter?

What kind of batteries does it use? Can it accept an external battery
pack of AAs?

Would you say it seems rugged or fragile?

Is the headphone voltage sufficient? I use a pair of MDR-V6
headphones, and some CD players don't seem to drive them well.

Thanks for anything you can offer on this...

Sean
From: sh09@ns1.cc.lehigh.edu (STEVEN HIGGINS)
Newsgroups: rec.audio
Subject: Re: A receiver as a wake-up alarm?
Date: 8 Jan 93 04:13:56 GMT
Organization: Lehigh University

>>Is it possible to use a stereo receiver as a wake-up alarm?

    Yup, and as source material may I recommend "TIME" by Pink Floyd?
    That ought to do the job......
    :-O

    
-- 

~Steve
sh09@lehigh.edu
From: ah157@cleveland.Freenet.Edu (Rob Henry)
Newsgroups: rec.audio
Subject: Sherwood CD-1000C Question,please help
Date: 5 Jan 1993 19:55:10 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: ah157@cleveland.Freenet.Edu (Rob Henry)
NNTP-Posting-Host: slc10.ins.cwru.edu



I have a sherwood cd1000c single disc cd player.
With certain disks,the disc goes in,spins and the disc indicator comes on
like there is no disc in the player.
I heard that I may be able to adjust 1 of the 3 pots in the player???
Is this true?
Laser intensity or something.
From: gt5708a@prism.gatech.EDU (Preston Hunt)
Newsgroups: rec.audio
Subject: Question about using 6 ohm speakers with 8 ohm only receiver
Date: 9 Jan 93 19:03:48 GMT
Organization: Georgia Institute of Technology

After shopping around for new speakers, I am more confused than ever
about impedances of stereo equipment.  The speaker terminals on the
back of my receiver carry the admonishment "Impedance: Use 8-16 Ohms."
Many of the speakers that I am thinking about buying are 6 ohms, and I
want to be sure it is okay to use them.

I realize that V=IR, and by reducing the resistance by one-fourth, the
receiver must generate 4/3 more current to achieve the same voltage.
This could potentially overheat the receiver.

So, why do speaker manufacturers make lower impedance speakers?  Do I
need to worry about getting only 8 ohm speakers for my receiver, or
will using 6 ohms be okay?

Thanks,
Preston

-- 
Preston Hunt (gt5708a@prism.gatech.edu) | Denuone Latine loquebar?
Georgia Institute of Technology         | Me ineptum.  Interdum modo
P.O. Box 35708, Atlanta, GA 30332       | elabitur.
Newsgroups: rec.audio
From: znpt01@trc.amoco.com (Norman P. Tracy)
Subject: S/PDIF Data rate, was: Re: How can different digital cables sound different?
Originator: znpt01@gpss43
Organization: Amoco Production Company, Tulsa Research
Date: Wed, 6 Jan 1993 16:00:09 GMT


In article <184785@pyramid.pyramid.com>, lstowell@pyrnova.mis.pyramid.com (Lon Stowell) writes:
> In article <gmaltby.38.726234819@unpcs1.cs.unp.ac.za> gmaltby@unpcs1.cs.unp.ac.za (Gavin Maltby) writes:
> >
> >CAn you tell me what is the effective rate of data transmission down
> >a coax link between transport and DAC?
> >
>    It will be over 1.4 mHz...figure it out yourself....32*44100 +
>    whatever overhead bits.
> 
>    And although I've been giving Pascal a rough time about cabling,
>    unless the cable is real garbage or damaged, I'd have to blame
>    the transmitter and/or receiver or power/grounding or RF
>    isolation for any errors in that area.
> 

Both the consumer S/PDIF and professional AES/EBU serial digital audio
interfaces use the same schemes for getting the samples back and forth.

Each sample is 32 bits long and transmitted in a structure called a "sub-frame".
The sub-frame contains 4 bits of pre-amble, 4 bits of auxiliary data, 20 bits
of audio data, 3 bits called validity, user, and channel status, and a parity
bit.  For CD and other 16 bit formats the last 4 bits of the sample are set
to zeros which are still transmitted leaving the sub-frame 32 bits long.  As
an interesting aside the standard actually allows the audio sample to be up
to 24 bits long by using both the audio and auxiliary data fields.  Like any
good standard setting committee (an oxymoron?) they allowed for future expansion.

Also you need to allow for the fact the data is transmitted using bi-phase
mark encoding with a clock embedded at twice the bit rate.

The calculation thus becomes:
sample rate * sub-frame length * 2 (for bi-phase) * 2 (for stereo) = frequency

For CD:
44.1k * 32 * 2 * 2 = 5.6448 Mhz
For DAT:
48k * 32 * 2 * 2 = 6.144 Mhz
For DAT/LP or other 32 kHz sampled audio:
32k * 32 * 2 * 2 = 4.096 Mhz

Even this is still a bit of an oversimplification.  Keep in mind this type
of calculation gives the FREQUENCY going down the cable, not the bit rate.
The bit rate number is half the numbers above because when talking data
rates you typically ignore the coding scheme and thus take out the 2x factor
for the bi-phase encoding.  Also due to the nature of bi-phase encoding the
frequency will vary from the numbers given above depending on the exact values
of the individual samples and subcode bits.

I would agrue that getting circa. 6Mhz signals down a wire requires paying
attention to cable impedance and termination.  The standards committees seem
to agree as they specify 75 ohm Z for consumer and 110 ohm Z for the balanced
professional implementation.

Above information from Crystal Semiconductor CS8401/2 Digital Audio Interface
transmitters data sheet "Appendix A- AES/EBU Reference".  The AES published
the final offical version of the spec. in 1992 series of their journal.

Norman Tracy
znpt01@trc.amoco.com
From: lancer@wpi.WPI.EDU (Stephe Lewis Foskett)
Newsgroups: rec.audio
Subject: Re: What the heck is a Scoopman?
Date: 8 Jan 93 11:15:48
Organization: ZikZak Corporation
NNTP-Posting-Host: wpi.wpi.edu
In-reply-to: mikef@hpcss01.cup.hp.com's message of Wed, 6 Jan 1993 15:59:17 GMT

>>>>> "mikef" == Mike Forman <mikef@hpcss01.cup.hp.com> writes:
mikef> It's really cool.  It, as you
mikef> know, uses stamp sized cassettes for recording.

How much do the casettes cost?  Are they durable?  And stereo?  let's
see...  12 bit, 32KHz, 90 minutes, stamp-sized...  Sounds just great
to me!  Does Sony send out product info on this thing?  And does it
use any compression like those OTHER digital formats?

mikef> The price at Yodobashi Camera in Shinjuku (Tokyo) is currently
mikef> about $600 for the Japan-only version.  It comes complete with
mikef> AC adapter, case, battery, cables, microphone, and one tape.

I'd bet it's more expensive from an import place here in the US...

.s.
--
- so spake lancer@wpi.wpi.edu -  - such is the way of the SysOp: -
- You are a bug. I am superior to you. I can squash you anytime. -
Newsgroups: rec.audio
From: tonyb@juliet.ll.mit.edu ( Tony Berke )
Subject: Re: Class-A-Stasis, FAQ?
Organization: M.I.T. Lincoln Lab - Group 43
	<1993Jan6.223426.1089@cmkrnl.com>
Date: 7 Jan 93 10:20:17

In article <1993Jan6.223426.1089@cmkrnl.com> jeh@cmkrnl.com writes:
    co940@cleveland.Freenet.Edu (Nicholas E. Damato) writes:
   > 
   > Hello, I don't know if this is an FAQ or not, however I thought
   > i'd ask it anyways.
   > I understand the basic principle behind class A, AB, A/AB etc.
   > but i was recently auditioning a threshold amp on a pair of
   > Thiel speakers. I was asking about the usual specs and the     
   > salseman said that threshold uses class-A-Stasis Amplification
   > with "Absolute-Zero" Dynamic headroom. What's the deal here?

   Marketing hype.  

I agree.  My guess as to the engineering behind the hype is that these
amps must have 100% regulated power supplies and big heatsinks, giving
them the same power output on peaks as they have for continuous signals.
The "Absolute Zero" crap sounds like a way of underscoring exactly how
overbuilt the amps are.  Sounds like fun to me !


Tony Berke
From: dbp0@ns1.cc.lehigh.edu (DENNIS B. PRICE)
Newsgroups: rec.audio
Subject: Retail vs. "Crutchfiled" vs. Wholesale ?
Date: 4 Jan 93 17:09:47 GMT
Organization: Lehigh University


 I've been shopping for a CD head unit for my Jeep, and after months of
 feature-comparing, advice from various sources good reliable and not, and a
 quick check on my credit card balance....  :-)  I've decided on a Pioneer
 DEH-780, with the removable faceplate (key for those of us with topless cars).

 I've seen it at Silo, Circuit City, and other retailers for as low as $419.
 This is still out of my price range.  Crutchfiled, who I have purchased a few
 things from in the past and been satisfied (they have the nice wiring
 harnesses and installation stuff), also advertizes this unit for $419.
 I have seen, however, in the back of Stereo Review and similar magazines,
 ads for "Wholesalers" at around $319.!!  That's 100 bucks less!.  Are these
 guys legit?  What am I not going to get if I order from these guys?  It seems
 too good to be true.  They take MC/Visa, so my I'm protected as a consumer.
 The say it has the manufacturer's US warranty, and some even offer a 30-day
 money back guarantee.

 Can someone explain to me a reason why I should *not* order from these
 "Wholesalers"?  What's "Factory Authoirized" mean vs. regular "Authorized" or
 "Distributor Authorized"?

 Reply soon.  I'm anxious!!

 Brad

 
Newsgroups: rec.audio
From: mike%jim.uucp@wupost.wustl.edu (Mike S.)
Subject: Re: Subwoofer dumb question
Organization: BITS, St. Louis, MO
Date: Tue, 05 Jan 1993 08:25:34 GMT

baldwin@frodo.colorado.edu (Dan "Viper" Baldwin) writes:

>	Thanks to all of you who gratiously answered my question. I guess
>the bottom line is that I have to find out if the cross over which controls
>the sub out on my reciever, a Yamaha RX-V850, filters out the frequencies
>below 200Hz which go to the main speakers. Does anyone know if the reciever
>does this ? 

If you are using the subwoofer line output, then no, it's not doing this.

>an alternative set up is to place the sub woofer between the main amp and
>the main speakers. Right ?

If the subwoofer you are using has speaker level inputs (and a crossover),
you can hook those up to the main speaker outputs of the Yamaha, and your
main speakers to the output terminals on the subwoofer.

Mike
-- 
mike%jim.uucp@wupost.wustl.edu
From: gmaltby@unpcs1.cs.unp.ac.za (Gavin Maltby)
Newsgroups: rec.audio
Subject: Re: speakers for classical music
Date: Mon, 11 Jan 1993 09:04:56 GMT
Organization: University of Natal, Pietermaritzburg, South Africa
NNTP-Posting-Host: pc047.cc.unp.ac.za

In article <43291@sdcc12.ucsd.edu> wsun@jeeves.ucsd.edu (Fiberman) writes:
>Path: ee.und.ac.za!shrike.und.ac.za!psgrain!uunet!zaphod.mps.ohio-state.edu!saimiri.primate.wisc.edu!ames!network.ucsd.edu!sdcc12!jeeves!wsun
>From: wsun@jeeves.ucsd.edu (Fiberman)
>Newsgroups: rec.audio
>Subject: speakers for classical music
>Message-ID: <43291@sdcc12.ucsd.edu>
>Date: 10 Jan 93 22:30:04 GMT
>References: <1993Jan9.204055.25877@nstn.ns.ca> <1993Jan10.140107.25425@news.ysu.edu> <C0nrvL.2Co@usenet.ucs.indiana.edu>
>Sender: news@sdcc12.ucsd.edu
>Organization: University of California, San Diego
>Lines: 7
>Nntp-Posting-Host: jeeves.ucsd.edu

>For all the experts out there:

>If money were no object, what speakers are the best for
>listening to classical music?

>-fm

Try Apogee Centaurs (Minors are very good value).  They are a hybrid
cone/ribbon.  The ribbon is very smooth in the mid-range and treble---
perfect for classical (and vocal too).  The familiar cone sound in the 
bass makes an excellent impression, too.  If you want more expensive,
then bigger Apogees (Caliper Signatures are excellent) and Duntech
Sovereigns are brilliant.

Cheers

Gavin
Newsgroups: rec.audio,rec.video,sci.electronics,comp.dcom.lans.ethernet
From: ctdonath@mothra.syr.EDU (Carl T. Donath)
Subject: Re: Help wiring new home for audio/video/phones/computer
In-reply-to: brennan@hal.com's message of 6 Jan 93 00:38:16 GMT
Organization: Syracuse University
Date: Wed, 6 Jan 93 12:26:38 EST

This might be helpful:

Linear Technologies has an interesting ad in EDN 12/24/92: "Send Color Video
1000 Feet Over Low Cost Twisted Pair", complete with schemtaic and 
implementation tips. Looks fairly inexpensive, especially considering the
savings in not using coax. 
--
  __________/ ctdonath@rodan.acs.syr.edu  Carl T Donath \________________
 / Why do people assume that this is the first time things have ever     \
/ been this way and things will stay this way forever?                    \
From: Matt.Ion@p106.f7040.n153.z1.ship.wimsey.bc.ca (Matt Ion)
Sender: UUCP@ship.wimsey.bc.ca
Newsgroups: rec.audio
Subject: How can different digital cables sound different?
Date: Sat, 09 Jan 1993 10:00:32 -0800

 JJ> Now, I'm really confused.  Most of the (bipolar) transistors in MY lab
 JJ> seem to show a Vbe of about .7 volts at saturation, but oddly enough,
 JJ> and right in line with the physics of the situation, the Vce is about
 JJ> .4 volts.

 JJ> Most of the TTL sitting there has substantially less than .7 v at
 JJ> zero.  Almost like it's one Vce saturation voltage, which
 JJ> isn't really very surprising when I look at the circuitry
 JJ> shown in the old TI handbook.  Looking at the TI handbook,
 JJ> most of the "0" levels are stated to be typically .2V, max .4.

 JJ> Most of the CMOS has very low values, once it's settled.  I mean
 JJ> VERY, it's lower than .2  Of course, the CMOS also has a quite
 JJ> different threshold of 0/1, as well, but why confuse the issue
 JJ> any more than it's already confused?

...keeping in mind that TTL requires 5 VDC supply.  Period.  Thus the
thresholds are set.  Most CMOS devices can handle a power supply anywhere
between 3V and 15V, and the thresholds of CMOS logic are defined as
percentages of Vcc rather than as a fixed voltage.
From: boop@cbnewsi.cb.att.com (joseph.a.lapenta)
Subject: Equipment For Sale
Organization: AT&T
Distribution: usa
Date: Tue, 12 Jan 1993 18:45:57 GMT




EQUIPMENT FOR SALE:

Hafler XL-280 power amp (145 W/channel).............$390

Hafler DH-110 pre-amp...............................$250

Denon DCD-910 CD player.............................$259

Spectrum 410 loudspeaker............................$269

*All equipment is in excellent condition and has original boxes
 and manuals.



Joe LaPenta
(201) 386-4883
Newsgroups: rec.audio
From: DPierce@world.std.com (Richard D Pierce)
Subject: Re: Bose Speakers
Organization: The World Public Access UNIX, Brookline, MA
Date: Mon, 11 Jan 1993 11:40:48 GMT

In article <726650872.AA00128@ship.wimsey.bc.ca> Matt Ion writes:
>
>I hear JBL burns in its large sub drivers by hanging them in an anechoic
>chamber, hooking them up to 120VAC/60Hz and running them for 24 hours. V^2/R
>or 120^2/8 gives you about 1800W power dissipation, CONSTANT.
>

Horsecrap on a variety of fronts. First, they don't do this. How do I
know? several reasons: I asked them, they said no; I worked for them, I
never saw them do it; there's no good reason to do it, it doesn't do you
much good and doesn't provide you with any real information; it's
ridiculously expensive tying up an anechoic chamber for burn-in tests; all
the burn-in in the world is done and over with in a minute or two anyway.

Secondly, your calculations of power are based on a flawed assertion. You
claim the impedance is 8 ohms, but ignore the fact that the real impedance
is much different, especially at low frequncies. Let's presume for the
moment that they DO use 120 VAC at 60 Hz (they don't, but let's pretend).
In all likelyhood, they dump the speakers in a relatively small test
enclosure that raises the resonance significantly above the free-air
value. Let's say it raises it to, oh, 60 Hz. Then they hit it with 60 Hz,
120 VAC. We might now find that the imnpedance at this frequency is not 8
ohms, but maybe 90 ohms (quite a reasonable figure, having measured it
fairly recently). Now, the power dissipation is no longer 120^2/8=1800
watts but 120^2/90=160 watts. Big deal.

If your going to "burn in a woofer", in all likelyhood, what you are
trying to do is excercise the suspension. It makes sense to do that at
resonance. This is the frequency that will give you maximum mechanical
excursion for minimum electrical power dissipation. There is nothing to be
learned in a production environment from the sort of test suggested above.
I suggest that it's merely a legend. Maybe having such a legend satisfies
some macho desire, bit it has no engineering or QC value.

-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |