HDTenEightyP/NetNews huggingface dataset:
From: brian@pawnee.eel.ufl.edu (Brian Gentry)
Subject: Re: Need Help W/ ISOBARIC Box Design!
Organization: UF EE Department (student)
Date: Thu, 1 Oct 92 21:44:39 GMT

In article <1a4ohiINN45r@usenet.INS.CWRU.Edu>, ae454@cleveland.Freenet.Edu (Paul Simundza) writes:
|> 
|> 
|>  My friend is Interested in Buying two Kicker 12 Competition speakers,
|> but a standard box to put the 12's in will not fit in his hatch, he
|> has a 88 hyundai Excel...its like 14' high max, about 38' wide, and
|> it has an angle where the seats are in the back. Its around 14-18 inches
|> (I think) deep, deeper on the bottom because of the angle...
|> 
|> Anyways, I hear Isobarics would be a good solution, what i need to know
|> is some info on these boxes(Design, shape etc...) and possibly how to 
|> figure out the dimensions knowing the space in the hatch...LIke the
|> Car audio Stores do....I don't want to be spending hundreds of extra
|> dollars when I could get the wood cheap, and my friend's dad has every
|> tool ever made almost! 
|> 
|> Any help would be GREATLY appreciated!
|> 
|>  
|> 
|> -- 
|> Paul Simundza                  | Cleve.Freenet: ae454@cwru.edu
|>                                | Compuserve: 71441.217@compuserve.com
|>                                | CSU(Internet): pauls@madnick.cba.csuohio.edu


You can design isobarik enclosures just like any other.  To be an 
isobarik system you need to seal two woofers together with a short,
low volume tunnel.  The easiest way is to bolt to drivers face to face
and seal the assembly into a sealed or ported box.  When designing
an isobarik enclosure, you do all of the math exactly the same except
that you cut the Vas in half as compared to one driver.  For example
if one brandX model Y woofer works best in a 2 cubic foot enclosure,
then 2 brandX model Y woofers sealed together (isobarik) will work
exactly the same in a 1 cubic foot enclosure.

As to the shape, it really doesn't matter as long as you don't constrain
the flow of air around the woofer.  In general non-parallel walled
enclosures produce less resonances (standing waves) than parallel wall
(rectangular solid) enclosures.  If you are going to use a rectangular
solid enclosure the best ratio is the golden section.  This is supposed
to put the resonances at 1/3 octave intervals.  To make a rectagular
solid enclsure with the golden section, make one dimension x long the next
one 1.61(x) long and the next 1.61(1.61)(x) long.  Using the equation
for volume of a rectangular solid V = 1.61^3(x).  So given a known volume
you can get the internal dimensions of the enclosure.

Questions or comments are welcome.

			Hope this helps,
		        Brian L. Gentry
		     (brian@sioux.eel.ufl.edu)
Newsgroups: rec.audio.car
From: brian@creek.eel.ufl.edu (Brian Gentry)
Subject: Re: speakers and enclosures
Organization: UF EE Department (student)
Date: Fri, 2 Oct 92 17:30:43 GMT

In article <1ab2qmINN360@bigboote.WPI.EDU>, walkerr@yaya.WPI.EDU (Robert A Walker) writes:
|> 
|> I've got two realistic 12 inch subs.  Go ahead, i know they aren't 
|> the best or even great, but I am on a seriously restricted budget an i 
|> picked them up for 50 bucks when a friedn of mine upgraded.  Now my 
|> question is I put the statistics for these speaker into the equation
|> Qts^2.87 * 15 * Vad and came up with a volume of 12.414 cubic foot 
|> ported enclosure.  Now is thi{ reasonable or is the equation wrong.
|> Qts = .38
|> Vas = 13.3

As someone else suggested PART of the problem is that the Vas figure
is very large (I assume it's in cubic feet).  The rest of the problem
is the equation.  This is equation gives you a system with the "maximaly
flat" response.  This is the only criterea it fills.  Most drivers don't
perform very well in their "optimum" enclosure.  For example the JL Audio
12-W5 has an "optimum" enlcosure size of ~6 ft^3.  In this enclosure
the system -3 dB point is ~20 Hz.  This is really impressive until you
look at the power handling in the low frequency region.  As I remember
this driver wouldn't handle more than about 15 watts below 50 Hz.
However, if you change the enclosure by making it smaller and moving
the tuning frequency, you can find an excellent compromise between 
power handling, low frequency extension, and passband ripple (flatness).
In the proper enclosure, this driver can handle a lot of power and
have clean low bass.

I suggest that you use an enclosure design program to simulate the
response of your driver in various enclosure sizes and tunings until
you reach the best compromise for your situation.
 
			Brian L. Gentry
		    (brian@sioux.eel.ufl.edu)
From: kmr4@po.CWRU.Edu (Keith M. Ryan)
Newsgroups: rec.audio.car
Subject: Re: Noise canceller
Date: 5 Oct 1992 00:14:38 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: kmr4@po.CWRU.Edu (Keith M. Ryan)
NNTP-Posting-Host: thor.ins.cwru.edu


In a previous article, ssave@ole.cdac.com (The Devil Reincarnate) says:

>
>  A simple question to net.wisdom:
>
>  How do active noise cancelling headphones work?  Anyone?
>  I got curious after I read in an Auto magazine that Toyota
>  is coming out with active noise cancelling inside the passenger
>  compartments in some of its 1994 models.  Must be an extension 
>  of existing noise cancelling headphones, n'cest pas?
>

	I am not quite sure what you are asking, ( mainly the headphones
part ). I know they are working on active noise cancellations. The basic
principle is that a computer senses the road noise ( by straticically 
located microphones ), and then issues commands to a sophisticated speak-
er array, reproducing the noise, but 180 out of phase. This will cancel
the noise out. While this would not be perfect, I have read estimates of
up towards 20 dB's worth of cancellations. However, one of the main problems
is that a major component of road noise are subsonics, which'll be hard
to install a economical method to null those. ( Could you imagine having
to buy subwoofers to make silence? I don't think it'll sell! ) Luckily
for most people, the lower noise only needs to be masked, not nulled. How
ever, all this takes sophisticated DSP, and is very expensive at this stage.

	I havn't heard anything about people wearing headphones while
driving thou. Isn't that illegal in most states?

-- 

	" It's time for Congress to tell the president to shove his 
	veto pen up his deficit! "  
					- Rep. Jim Traficant.
From: jms@a.cs.wvu.wvnet.edu (J Michael Salkovick)
Newsgroups: rec.audio.car
Subject: T.M.Haddock where are you?
Date: 30 Sep 92 12:52:52 GMT

Mr. Haddock,

	Please send me your internet address...I have been trying to
reply to your mail message of two weeks ago with no success...

	Sorry to waste width...

Mike
-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
J. Michael Salkovick  jms@a.cs.wvu.wvnet.edu | "Tryin' to be a pimp...
WVU Computer Science Department              | ...Drive a Nissan Sentra" - YoYo
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
From: picano@en.ecn.purdue.edu (Silvio Picano)
Newsgroups: rec.audio.car
Subject: Concord HPL-520 Car radio part & info needed.
Date: 28 Sep 92 20:58:23 GMT
Organization: Purdue University Engineering Computer Network


Hi.

I am in need of a on/off switch assembly for my car 
radio.  The assembly is a standard on-off-volume 
control, bass-treble control (or fader control...I 
cannot remember for sure), and the post assembly 
for standard (DIN) radios.

Model: Concord HPL-520

Does anyone know if this is somewhat of a "standard
part" (the inside switch wiring looks complex)?

Does anyone know if "Concord" still makes car radios, 
or what their phone number might be?

Thanks.
Silvio
Newsgroups: rec.audio.car
From: finnegan@invader.navo.navy.mil (Kenneth Finnegan)
Subject: BOSE 1401 Car Stereo
Reply-To: finnegan@navo.navy.mil
Organization: Grumman Data Systems	
Date: Mon, 28 Sep 1992 13:59:00 GMT
Nntp-Posting-Host-[nntpd-5425]: invader.navo.navy.mil

This talk about 2ohms versus 4ohms made me think of this:

In 1983, I bought a Bose 1401 stereo system consisting
of an amplifier (actually 4 amps in 1 box), and four
speakers.  Since then, the system has been installed in
5 different cars, and currently resides in my Isuzu
Trooper.  I am amazed that the speakers and amp have
held up as long as they have.  They still sound very
crisp, and there is no sign of physical deterioration
on the speakers at all.

Each of the four amps delivers 25W, but the catch is that
the system only runs at .25ohms.  Yes, one quarter of
an ohm speakers.  The amp is covered with warnings about
not using any other speakers than the ones that were 
supplied with the unit, or serious electrical damage
will occur. The power lead is equipped with a 25 amp
fuse, and the amp gets fairly hot even during light
use.

Anyway, I was wondering if anyone else ever had any
experience with this system, and why Bose dicontinued
their retail car stereo production.  I know they still
produce units for Infiniti, GM, Nissan, etc. for
use as factory installed units, but I haven't seen
any retail Bose car stereo stuff in years.  Anyone?

Kenneth
finnegan@navo.navy.mil
Newsgroups: rec.audio.car
From: jreiser@scott.skidmore.edu (jason reiser)
Subject: Re: ALL YOU MOTHER FUCKERS BETTER READ THIS!!!!!!!!!!!!!!!!!!
Organization: Skidmore College, Saratoga Springs NY
Date: Sun, 27 Sep 1992 09:40:47 GMT

bs753@cleveland.Freenet.Edu (Brett J Grimes) writes:
> 
> ALL YOU MOTHER FUCKERS HAVE THAT GOD DAMN RAP SHIT, GOING DOWN THE
> MOTHER FUCKING STREET AT 3:00 AM IN THE FUCKING MORNING SHIT HAS 
> GOT TO STOP. IM SICK OF YOU MOTHER FUCKERS!!!!! TURN THE FUCKING SHIT
> DOWN. I DON'T WANT TO HEAR THAT SHIT, SOME OF US HAVE A GOD DAMN JOB AND
> HAVE TO GET UP EARLY.  SO FUCK ALL YALL!!!!!!!!!


Well, everyone is entitled to their free speach... that is, until that
person's sysadmin says they're not.  Just something to ponder...

				- Jason

------------------------------------------------------------------------
"Sometimes I think that the surest sign that intelligent life exists
elsewhere in the universe is that none of it has tried to contact us."

"People think it must be fun to be a super genius, but they don't
realize how hard it is to put up with all the idiots in the world" ;-)

					- CALVIN
-------------------------------------------------------------------------
(Not just another sig with a quote, but one that's been custom made
for the situation... WOW!)
From: cjm9321@hertz.njit.edu (The InfoMan)
Newsgroups: rec.audio.car
Subject: Re: Speaking of annoying things...
Date: 27 Sep 92 19:58:11 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.

In article <1a4fifINNm0j@usenet.INS.CWRU.Edu> kmr4@po.CWRU.Edu (Keith M. Ryan) writes:
>
>	The most annoying vehicles in my book are the darn ice cream trucks!
>When I was younger, I hated those darn trucks, with their cutesy jiggles
>playing. I always wanted to run out in the street with a bazooka and blow
>it sky high!  And I still want to! <grin>
>-- 
>
>	What God wants Gods gets... God help us all

	Well, when I was in NYC a while back, there was one that was on
fire. My dream come true.

	What happened was that the desiel fuel caught on fire.

-- 
M A D E   .   . .---. .---.    \  Buy U.S.A. products,  /    xxxxx ==========
  I N     |   |  \    |___|    <     It's YOUR job.     >    xxxxx ========== 
 T H E    |   |    \  |   |    <  Christopher J. Massa  >    ================
-------   `---' `---' '   `    / cjm9321@hertz.njit.edu \    ================
From: burens@4ccvw70.scg.hac.com (Mark Burens)
Newsgroups: rec.audio.car
Subject: Audio ignorant***
Date: 2 Oct 92 04:50:36 GMT
Reply-To: burens@hacgate.UUCP (Mark Burens)
Distribution: la
Organization: Hughes Aircraft Co., El Segundo, CA


There, I've said it.  I admit it.  I don't know the first thing about
audio electronics.  I wouldn't know an ohm if it bit me in the butt.

If someone would like to take the time and explain some of the basics,
I'ld appreciate it.  Or maybe even suggest where a novice could begin
his quest for knowledge.

But first,  my immediate problem:
---------------------------------
My wife bought me an (dare I say it) Audiovox 958ETR 50W unit.  I assume
this unit has a built-in 50W amplifier.  It has leads for four (4) speakers
plus preamp leads.

I currently have it wired to four (4) Jensens rated at 30W continous (60W
max) and the preamp leads are'nt in use at this time.  Positive and negative
leads run from the unit to each speaker with the negatives returning near
the unit to a common ground.  I don't know what gauge wire I'm using but,
suffice it to say it's the size that's provided with the speakers.

The problem is when the volume gets to a certain extent, the unit ceases
to produce music.  It's still on, it just dos'nt make any noise.  If I
turn it off and then back on is O.K. until I turn it up too much.

Is this just a bad brand of stereo?  Is it just a bad idea to have a
head unit with a built-in amp (get's too hot and shut's off)?  Are my
wires too wimpy to handle the job?  Any ideas?

                                    Help!
From: sdexter@scotty.ucr.edu (scott dexter)
Newsgroups: rec.audio.car
Subject: Re: Sony component speakers
Date: 5 Oct 92 19:27:05 GMT
Article-I.D.: galaxy.22696
Organization: University of California, Riverside

In article <111250005@hplred.HP.COM> moussavi@hplred.HP.COM (Farshid Moussavi) writes:
>Hi all!
>
>I was wondering if anyone has any good/bad impressions about 
>Sony's 5.25" component systems, i.e. the XSHL25,35, and 45.
>They seem  like fairly decent component systems for a good price
>(They are no Boston's or MB Quarts, I know).  Any insights
>would be greatly appreciated.  Thank you.
>
>Farshid


I have listened to the XSHL25 's and 26's and was impressed with the woofer.  Solid, accurate bass with out a lot of distortion.  The tweeter, however, was nowhere to be heard (read: tweet got lost; just couldn't hear it).  If I can get a chance to hear the 35's or 36's (have upgraded tweeter), I would probably buy them.  The tweet on the 25's and 26`s just isn`t comparable to the woofer Sony uses with it.  If the tweets are any better on the 35's then they (IMHO) are *VERY* close to Boston's.  (Haven't he



ard MBQ's).

Listen to EVERYTHING YOU CAN -- and TAKE YOUR TIME

   That's the only way you can be happy --

Hope this helps--

Scott
----------------------------------
sdexter@ucrengr.ucr.edu

-- Don't look for answers on the NET;  That's what TA's are for 
Newsgroups: rec.audio.car
From: jreiser@scott.skidmore.edu (jason reiser)
Subject: Re: 2 ohms vs. 4 ohms
Organization: Skidmore College, Saratoga Springs NY
Date: Mon, 28 Sep 1992 02:00:30 GMT

jsc52962@uxa.cso.uiuc.edu (Jeffrey S. Curtis) writes:
> If I can get a two channel amp that's stable at 2 ohms cheaper than a
> four channel amp, and both produce roughly the same net power at each
> speaker, is there any reason not to buy the two channel amp? Does running
> speakers in parallel introduce any problems that would make me not want
> to do this?
> 
> Jeff

So Jeff, let me get this straight.  You're comparing (for example) a
50x2 amp running 4 speakers (2 to each side in parallel) thereby
producing as much as 50 watts to each speaker (100x2 into 2 ohms) to a
50x4 amp running 4 speakers at 4 ohms each.  The difference?  Well,
you are forced into using passive crossovers if the drivers in the
first example differ, where a 4 channel amp does not limit you in this
way.  More importantly, a 2 ohm load has less damping and might
(depending on the quality of the amp) sound kind of mushy. (lacks
punch and acuracy).  A quality amp should not have a problem with a 2
ohm load, but in general there is less distortion and more damping in
a 4 ohm set-up.

Hope I answered your question... I wasn't positive that that's what it
was.

					- Jason
From: kmr4@po.CWRU.Edu (Keith M. Ryan)
Newsgroups: rec.audio.car
Subject: Re: SUB UNDER SEAT/KENWOOD AM
Date: 5 Oct 1992 22:35:47 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: kmr4@po.CWRU.Edu (Keith M. Ryan)
NNTP-Posting-Host: slc12.ins.cwru.edu


In a previous article, sdexter@scotty.ucr.edu (scott dexter) says:

>>     My name is Bill an installer.  I have never heard of a box for
>>under the seat. Although many people have asked this question.  Subs
>>will work any were in the car with the proper enclosure. In other words
>>don't waste your time with this idea.
>>     I am also a Kenwood supplier and if you need this cable call me.
>>I know I can get it for less.   513-651-9695

>-- doesn't MTX make some boxes that have 4" woofers and a passive radiator that are DESIGNED for under-seat applications??  - Saw it in Fall/Winter (91/92) Crutchfield catalog.
>
>-- also, no idea is not worthy of some thought and time ....
>

	Okay, I know the one you're talking about. Kicker also makes a set
with 5 1/4" woofer/passive. However, there is no way that these can reproduce
serious bass, or even decent bass, if one wishes to keep all the variables
within desent ranges. Meaning, a small woofer CAN put out deep bass, but 
don't ask it to have large output. The TDL's puts out deep bass just using
one 6 1/2", yet their enclosures are rather big, and their efficiencies are
below average. In order to fit under a normal seat, the box has to be rather
shallow, and it can not be too long or wide either. Many woofers themselves
could not fit under a seat. You'll get much better performance by putting
the woofer in the door, and sealing it reasonably. And, they won't be muffled
by the seat.
 
	There is a rather advanced technique of building a wide, but
shallow enclosure UNDER the floor board, and having the woofer firing
up throu a hole in the floor. ( usually under your calves, not your seat ).
One example is the Ferrerri Mondial installation featured 2 or so years
ago in Audio. 

	In addition, some model cars with front wheel drive still have that
center bump, yet has no transmission linkage in it. I have seen a system
where they used that, form fitted a fibreglass enclosure, and covered the
bottom with a aluminum plate, and then having twin 8" ers firing up through
the hump, between the center console and seats. However, this is also a
very advanced form, only highly skilled and experienced installers can do
this kind of work! 
	Maybe someday....   :-)


or:

	 			Dash
	/~~~~~~~~~~~~~~~~~~\~~~~~~~~~~/~~~~~~~~~~~~~~~~~~\
               |  |         \        /
           ____|__|____     |  /~~\  |
 	   ~~~~~~~~~~~~	    | |  <-|-|----- Woofer
			    |  \__/  |
                            |  /~~\  |
 		 	    | |  <-|-|----  Woofer
 			    |  \__/  |
        /~~~~~~~~~~~~~~~~~~~~~\     /~~~~~~~~~~~~~~~~~~~~~\
       |    Drivers Seat       |   |	Passenger's seat   |

-- 

	" It's time for Congress to tell the president to shove his 
	veto pen up his deficit! "  
					- Rep. Jim Traficant.
Newsgroups: rec.audio.car
From: jsc52962@uxa.cso.uiuc.edu (Jeffrey S. Curtis)
Subject: Jensen 3269 vs. Sony XS-6930
Organization: University of Illinois at Urbana
Date: Wed, 30 Sep 1992 18:10:10 GMT

I was all set to go buy a pair of Jensen 3269's (the model just below the
current model listed in Crutchfield - 3469) when I stopped by a local
dealer and saw a pair of Sony XS-6930's for the exact same price.  Does
anyone have any experience with either of these sets of 6x9"s, or have
horror stories about either company? The specs on both speakers are
almost identical:

	Jensen		Sony
	------		----
sens	92dB		92dB
range	30-22kHz	30-30kHz
nom	60W		40W
peak	160W		160W
price	$79.97		$79.00

If anyone has any recommendations, please *email* them to me (since I
need to buy these within about 36 hours, and I know how much most of
us hate seeing the "X vs. Y recommendations" posts :-) ).  Thanks!

Jeff
--
*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*
+ Jeffrey S. Curtis sidewinder@uiuc.edu + "Watch the world argue / Argue with +
* "To be great is to be misunderstood." *  itself / Who's going to teach me / *
+ "Insist on yourself - never imitate." +  peace and happiness?" -- INXS      +
*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*
From: kirk@hpcc01.corp.hp.com (Kirk Lindstrom)
Newsgroups: rec.audio.car
Subject: Re: CDs for car stereo
Date: 6 Oct 92 15:49:21 GMT
Organization: Shredding the water of SF Bay, HP-OCD

I like:

Dave Grussin - "Migration" for overall system testing.  Good subwoofer tester
as well as mids and highs.  Great jazz for those of us that love it.

Telarc - "Timewarp":  First 20 seconds of "Alsosprach zurathruster sp?" can't
be heard on most subs.  I'm told it is a pure 16 Hz signal and most speakers
feabily try to play the first overtone.  I have yet to hear a car sub play
this note (though I haven't listened to all that many - just a few shops
where the owners didn't know squat - one even liked green pens on CDs!)

Telarc - "Bachbusters":  tweeter tester to the max.  Very pure notes played on
a synthesiser.  Very good lows also on some tracks.  Cheap-o speakers can't
play the pure notes.  Good for testing system noise also.

Pink Floyd's "Dark Side of the Moon" is decent, but both my home and van
systems have no problems with it.  Good for showing off.

I think the two Telarc's will point out where one can improve their systems
while Migration and Dark Side... are good for enjoyment.

Accoustic Alchemy - Back on the case:  Is a new one I'd put in the same
category as "Migration" - great wide range sound.

Kirk out
Newsgroups: rec.audio.car