HDTenEightyP/NetNews huggingface dataset:
From: bstdenis@mailbox.fwrdc.rtsg.mot.com (Brian St. Denis)
Subject: improved bass performance
Organization: Fort Worth Research and Development Center, Motorola, Inc.
Date: Mon, 14 Dec 1992 16:47:19 GMT

I have an (one) MTX Road Thunder Pro 12" in the recomended vented box being
driven by a 50 watt alpine amp bridged to 100 watts (roughly).  I do not have
it crossed over in any way ie. it plays all frequencies.  I am considering
getting an MTX electronic crossover.  What type of performance boost should
I hear once it is crossed over?  Is there a reason not to get the MTX crossover?
Will the bass appear to get "lower" after the cross-over?

Thanks for any advice.  And, if there are any other significant differences in
sound performance after crossing it over that I have not asked about, please
let me know.

-Brian
Newsgroups: rec.audio.car
From: tom@dynamo.ecn.purdue.edu (Tom McCain)
Subject: Re: Old Alpine Eq.
Organization: Purdue University, West Lafayette, IN
Date: 20 Dec 92 02:13:51 GMT

srw8050@ritvax.isc.rit.edu (Pez) writes:

: I'm looking for information on an old pre-amp eq. model #3011 I 

That is a 3311.

: believe.  I'm interested in knowing which wires go where.  None of the 
: wires are tagged and I don't have the manual.  I purchased it used in the
: hopes of being able to control my subs with it.  Anyone who can help
: please send e-mail

I used to have one before I purchased my current 3331.  The should be
3 DIN plugs hanging from the back.  One is front amp, one is rear amp,
and the last is sub-woofer amp.  As for the wires in the small white
plug.  I can't remember.  Call Apline...?

--tom
--
	    Tom McCain            tom@dynamo.ecn.purdue.edu


 The world is coming to an end!  Repent and return those library books!
Newsgroups: rec.audio.car
From: demaine@ee.ualberta.ca (Cal Demaine)
Subject: More Ramblings on Aperiodics
Organization: University Of Alberta, Edmonton Canada
Date: Mon, 14 Dec 1992 21:16:18 GMT

I called Speakerworks today.  It seems as if their aperiodics are different
from Autosound 2000's in some ways.

Anyway: I called.  I spoke with some nice fellow who seemed in the know.
Here's what I heard.

  - Cost for 2 membranes suitable for 2 12" subs: $500!

  - They send you the membrane material, and the calculations to work out
  what size of box you require, and (I'm guessing) the surface area of the
  membrane to use.

  - You have to sign a Non-Disclosure Agreement saying that you won't tell
  anyone anything about the design, etc.

  - The size of box required is quite small: He asked what the recomended
  volume for the driver was (I said 2-3 cubic feet) and told me that with
  membranes, I'd require only .4-.5 cubic feet!  Holy Bibles Batman!

  - No mention of any sort of active normalization network, such as AS2000
  includes.

  - The membrane material can (should) be carpeted.  That is to say, it's
  probably unbelievably ugly when not covered.

  - The trunk must be sealed from the passenger compartment.

Hmmm.  Now for the interesting part:

  - For $1000, I could become a dealer for these things.  For that much,
  they send me all the information, and I get to install them for whatever
  I want, whenever I want.         

  - Again, a Non-Disclosure Agreement is required.

  - For the $1000, they provide the necessary calculation information and
  enough material to make one enclosure.  After that, I just find a local
  source for the material.

So, what all this says to me is that:
    A) The material is easy to come by, if you know what it is.
    B) The scheme is simple enough that there is serious risk of everyone
       figuring it out and doing themselves for cheap.

Well, then, not to put Speakerworks out of business, we should continue trying
to figure out how this whole thing works.

  Questions? Comments? Payments?

     - Cal

-- 
--------------------------------------------------------------------------------
  - Cal Demaine                   | "You shot him in the back!"                 
    (demaine@bode.ee.ualberta.ca) |    "His back was to me!"  - El Diablo    
--------------------------------------------------------------------------------
Newsgroups: rec.audio.car
Subject: HOOK SUBS TO A FACTORY STEREO????????
From: $sawchukjr@brandonu.ca
Date: 17 Dec 92 14:06:04 CST
Organization: Brandon University, Brandon, Manitoba, Canada

I own a 1989 Dodge Shadow with the factory deck in it.  I want to leave it
factory, but would also like to install subs in the hatch. Is it permissable
to just splice a line off the back speakers, put RCA's on the ends, then
connect it to an amp with a built in crossover, or is there more to this??
I have heard many stories by locals who think they know what they are talking
about, including some who are considered professionals. (Sometimes I have to
wonder) Please email me your knowledge in this subject.  It is greatly
appreciated.   Thanx.

Jason
Newsgroups: rec.audio.car
From: eddys@citrus.SAC.CA.US ( Steve Eddy )
Subject: Re: CLASS A/MOSFET
Organization: Citrus Grove Public Access ( 916 ) 381-5822    Sacramento CA.  USA
Date: Fri, 18 Dec 1992 00:52:06 GMT
X-Newsreader: Tin 1.1 PL4

blasjw@ntmtv.UUCP (Joseph Blas) writes:

:  I wouldn't say that Class A car amps are unheard of.  Soundstream
:  makes Class A amps.
 
   Well, Soundstream SAYS they make a class-A amplifier. But the sample of
one of their Class A 100 amplifiers was NOT a true class-A amplifier. It was
biased somewhat higher than typical A/B amplifiers, but class-A it was not.
There was also too few output devices and not enough heat sink to allow full
class-A operation. But if there's one thing I've learned in my research into
car audio, it's that manufacturers can bloody well say anything they want
about their gear. Like Jenson's "passive equalizer" (the
PEQ-Somethingorother). 

se

-- 

# Where no man has gone before.                   eddys@citrus.SAC.CA.US
#   *default* .sig file                      csusac.ecs.csus.edu!citrus!eddys
# The undiscovered land.                                   /\../\
From: keys@starchild.ncsl.nist.gov (Lawrence B. Keys)
Newsgroups: rec.audio.car
Subject: Re: How many remote leads?
Date: 17 Dec 92 13:42:41 GMT
Distribution: na
Organization: National Institute of Standards & Technology

In article <1992Dec16.184946.6607@njitgw.njit.edu> cjm9321@hertz.njit.edu (The InfoMan) writes:
>In article <17565@umd5.umd.edu> ui68@linus.umd.edu (Bill Kyte) writes:
>>
>>   I have a small question for the net.  How many leads can you run off of 
>>the head units remote wire? I want to run two or three amps and don't know
>>what to do with the other two remote leads from the amps.
>>Anyone's help would be greatly appreciated.
>>       Thank you
>>                  -Bill
>
>	Crutchfied has something about this in one of there free
>literature booklettes. They say to use a relay (I forgot which one)
                                                ^^^^^^^^^^^^^^^^^^^^

The Crutchfield booklet is called "The Installation Specialist".  It's
free when you place an order.


>connected to the remote of the head unit so that it switches to a fused
>wire connected to the battery. Then the output from the relay would be
>coming directly from the battery so you can connect that wire to a
>distribution block.
>
>					Hope that helps!


                                                  .  
                                                 /                
Larry                            __/    _______/_                 
keys@csmes.ncsl.nist.gov       /                  \               
                          _____     __     _____    \------- ===
            ----------- / ____/   /  /   /__  __/              \
         /     ___    /  / ___   /  /      / /    ____          |
        |    /      \/ /__ /  | /  /__  __/ /__ /       \      / 
        /___         \_______/ /_____/ /______/            ====OO
            \       /                           \       /         
                -                                   -
       ---------------- FAHRVERGNUGEN FOREVER! --------------------            
            The fact that I need to explain it to you indicates
            that you probably wouldn't understand anyway!
       ------------------------------------------------------------
From: hhtra@usho72.hou281.chevron.com (T.M.Haddock)
Newsgroups: rec.audio.car
Subject: Re: Orion telephone number?
Keywords: Orion
Date: 15 Dec 92 19:27:34 GMT
Organization: Chevron

In article <1gl0gkINNk65@rave.larc.nasa.gov>, bell@hops.larc.nasa.gov (John Bell) writes:
|> The subject says it all. Does anyone know the telephone number for Orion? Or,
|> does anyone know of any other place where I can get a service manual for an
|> Orion 250SX?

 The number is   602-730-8200

 You might try  1-800-234-5678  but this may be an ORDERS ONLY number.

 TRAVIS
Newsgroups: rec.audio.car
From: ravalent@mothra.syr.EDU (Bob Valentine)
Subject: Re: Class A MOSFET Power Amp for sale...
Organization: Syracuse University, Syracuse, NY
Date: Sat, 12 Dec 92 20:05:26 EST

In article <1992Dec11.001832.13833@henson.cc.wwu.edu> n8842401@henson.cc.wwu.edu (Matthew Stearns) writes:
>veloovet writes:
>
>>    I have a Bolt MOSFET car power amp for sale
>>    Here are some of the specifications:
>>        Class A...
>>        Full MOSFET power supply...
>
>You of course realize that "class A" refers to a type of 
>power supply, and "MOSFET" refers to another type of 
>power supply.  No one amp can be both!  
>
>...Just thought I'd point this out...

Nope.  "Class A" refers to the amplifier's output stage.  It's the 
best sounding (lowest distortion) class, but it sacrifices on power
output.  MOSFET would be reffering to the p/s in this case.   

Care to explain what a "class A" p/s is?

________________________________________________________________________
\ The name:            -->   Bob Valentine  <--                        /
/ The address:      --> ravalent@mailbox.syr.edu <--                   \ 
------------------------------------------------------------------------
From: cjm9321@hertz.njit.edu (The InfoMan)
Newsgroups: rec.audio.car
Subject: Re: Can I run car stereo on battery charger?
Date: 17 Dec 92 07:02:47 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.

In article <1992Dec16.155512.45695@kuhub.cc.ukans.edu> thompson@kuhub.cc.ukans.edu writes:
>Hello all,
>
>I have a Clarion 9772RT pull out car stereo tape/receiver.  I also have
>a Kenwood 50x2 watt amp, and two Sony 6x9 speakers.  All of this equipment
>is sitting in my room doing nothing (I won't have a car for a while).
>
>I had an idea about how to use this car stereo equipment with the house
>electricity (110 volt I guess).  Can I use a car battery trickle chargerer?
>I can get a 10 amp one for $30.  Am I right in assuming that a 10 amp
>charger charging at 12 volts (car voltage) will yield (10 * 12) 120 watts
>of power before overloading?  I thought I heard that amps * volts = watts.
>Is this true.  If it is, is this a safe way to run my car stereo on my
>house current?  I could use a surge protector to prevent spikes.  Is there
>anything that I should be warned about that might damage my equipment by
>doing this?  
>
>I await any responses.  Thanks.
>
>-- 
>| Charles A. Thompson      | thompson@ukanvm.cc.ukans.edu        |
>| University of Kansas     | thompson@ukanvax.cc.ukans.edu       |
>| > They call me SkiBum <  | 32 bit OS/2 2.0 is for you!         |
>|----------------------------------------------------------------|
>| Listen to Rush Limbaugh from 12-3 EST on the radio EVERYWHERE! |
>------------------------------------------------------------------


	I might be wrong but I think that is a VERY bad mistake.


	The best way to do it would be to get a car battary and connect
it to the battery charger and start from there.


	Well that's probably not the best way, I would assume the best
way would be to get a transformer (Input=120V ac, Output 12V DC)
probably from RS and splice the wire or something.



		I may be wrong on the above, but I'm pretty sure your
idea will not work but destroy your equiptment.

-- 
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: cjm9321@hertz.njit.edu (The InfoMan)
Newsgroups: rec.audio.car
Subject: Re: Class A MOSFET Power Amp for sale...
Date: 15 Dec 92 14:32:00 GMT
Organization: New Jersey Institute of Technology, Newark, N.J.

In article <1992Dec13.183539.20822@nmt.edu> maley@nmt.edu (Mark Maley) writes:
>In article <Bz56Ax.IGJ@citrus.SAC.CA.US> eddys@citrus.SAC.CA.US ( Steve Eddy ) writes:
>>n8842401@henson.cc.wwu.edu (Matthew Stearns) writes:
>>: veloovet writes:
>>: 
>>: >    I have a Bolt MOSFET car power amp for sale
>>: >    Here are some of the specifications:
>>: >        Class A...
>>: >        Full MOSFET power supply...
>>: 
>>: You of course realize that "class A" refers to a type of 
>>: power supply, and "MOSFET" refers to another type of 
>>: power supply.  No one amp can be both!  
>>: 
>>: ...Just thought I'd point this out...
>>
>>   You of course realize that "class A" refers to a type of biasing scheme
>>which is applied typically to amplifier output stages and has nothing to do
>>with power supplies, and "MOSFET" refers to a type of transistor which can
>>be used in power supplies OR amplifier output stages. 
>> 
>> ...Just thought I'd point this out...
>>
>>se
>>
>It is true that an amp can be of class A output design and at the same time
>utilize a MOSFET power supply, but how likely is it to have a true class A
>amplifier which delivers 25w x 4 into 4 ohms powered by a 12V battery?
>Unless my knowledge of class A amplifiers is lacking, I believe that such
>amps have a mere 20% theoretical efficiency.  This would mean that our Bolt
>amp would consume a whopping 500 watts.  Does this seem in the least bit
>practical?  I ask you fellow car audio buffs who, like me, have never heard
>of an amplifier manufacturer named 'Bolt' whether or not this advertisement
>seems in the least bit tainted?  If perchance this is a ligitimate ad, I
>apologize to the owner and ask him to post some more specs on this wonder-
>amp, for i may have an extra $100 obo to spend (besides, my heater isn't 
>working well and I assume runnning this thing into 2 ohms could create
>at least 800 watts of heat, not to mention 200 watts of pure linear
>music power.  Seems like an excellent investment to me!!)
>
>			Mark
>
>maley@jupiter.nmt.edu

	I just want to point out to Mark and anyone else that doesn't
know, is that Bolt is a side company of Orion. Just like Sedonia is of
PPI. They did this to appeal to the "cheaper" crowd.


-- 
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: vincent@garnet.berkeley.edu (Vincent J. Lee)
Newsgroups: rec.audio.car
Subject: Question about Bolt Amps.
Date: 14 Dec 1992 05:38:01 GMT
Organization: University of California, Berkeley
Distribution: world
NNTP-Posting-Host: garnet.berkeley.edu

I am interested in purchasing a Bolt amp from one of my fellow
netters. It is a Bolt Professional series II Model Bt-504
It is rated 200 watts supposedly 4 channel. It is MOSFET class
A circuitry. However, as I'm told the two cannot go together. A 
local stero installer said that the quality was poor and that
it would end up burning out on me before anything. Anybody who
has carnal knowledge of this stuff please let me know. I originally 
wanted to drive a set of 6x9 for my Integra but now I'm told the
speakers won't fit. So I've decided to upgrade the speakers to a set
of 6.5 inch mid-bass speakers with tweets, if I can find them. So
please, if anybody knows if this amp is good and good for my application
please let me know. Thanks.
From: Emery@cup.portal.com (Marcus T Emery)
Newsgroups: rec.audio.car
Subject: What causes "hissing" noise with engine on?
Date: Fri, 18 Dec 92 10:17:37 PST
Organization: The Portal System (TM)
Distribution: world

Hi guys,
What causes the CD/AM/FM in the car to make hissing noise that goes
with the way you rev up the engine?  At times, it's sounds like I have 
a turbo in my car, which is neat, but on the freeway the noise gets
anoying after a while.
From: kirk@hpcc01.corp.hp.com (Kirk Lindstrom)
Date: Wed, 16 Dec 1992 17:55:56 GMT
Subject: Re: CLASS A/MOSFET
Organization: Shredding the water of SF Bay, HP-OCD
Newsgroups: rec.audio.car

>Oh, I'm getting sick of this.  ANYWAY, I do believe that in many car-audio
>circles, MOSFET refers only to the transistors used in the switching power
>supply.  There are notible exceptions, of course.  But I won't note them.
>Considering the unit, I would be surprised if it was anything but a MOSFET
>power supply.

MOSFETS are used in many home audio amps that want to drive low impedance
loads and I'm pretty sure the Bolt amp uses them for output devices.
Problem is, MOSFETS sound much worse than transistors in my opinion
in output stages.  They ARE much cheaper and easier to make which is
why they are popular.

A $1200 Hafler amp uses 24 parallel MOSFETS so it can nearly drive a
short and arc weld your speakers.  Of course, other amps sound better
but don't do such a good job of welding.  8-)

Kirk out
=> "We are what we pretend to be."  -  Kurt Vonnegut Jr.
+---------------------------------------------------------------------+
| Kirk Lindstrom - OCD Product R & D | Hewlett-Packard Co.  M/S: 91UA |
|   Engineer/Scientist, Hardware     |                                |
|------------------------------------| Optical Communication Division |
|       kirk@hpoclpa.hp.com          |                                |
|    Kirk Lindstrom / HP0100/UX      | 370 W. Trimble Rd.             |
| ph 408 435 6404 | fax 408 435 6286 | San Jose, CA  95131-1096       |
+---------------------------------------------------------------------+

Newsgroups: rec.audio.car
From: brian@hopi.eel.ufl.edu (Brian Gentry)
Subject: Re: Books, FAQ's etc
Organization: UF EE Department (student)
Date: Fri, 11 Dec 92 20:14:48 GMT

In article <1992Dec8.094827.29963@csd.uwe.ac.uk>, ir_johns@csd.uwe.ac.uk (Ian Johnson) writes:
|> 
|> Help! I'd like to start improving my audio system, unfortunately
|> my knowledge is close to zero. What I'd like to know is of books
|> FAQ's and any other good sources of info so that I could answer
|> questions such as:

|> 1. If a speaker is rated at 300W Max. Music Power, what wattage
|>    would be sensible to power it.

As Kirk said, you kind of have to ignore most manufacturer's ratings.
Very good speaker manufacturers like JBL, EV, etc. will give you information
on how much power their speakers can handle at certain frequencies AND
in certain enclosures.  In the case of bass drivers, the enclosure is
one of the most important criteria for how much power the driver can
handle. 

|> 2. One speaker 15 inch powered by a 400W amp vs. 2 x 10 inch by
|>    200W, which would be loudest , best & why?

Kirk already totaly covered this one....

|> 3. Sensitivity is quoted as Db @ 1 watt @ 1 metre, what does the
|>    figure tell you?

This figure is subject to how the manufacturer measured it, but here's what
it's supposed to be:  If you put 1 watt of pink noise (equal energy per 
octave) into this speaker and place an SPL measurement device 1 meter
away from the face of the driver, the device should give you this rating.
So, for a 91 dB @ 1 watt and 1 meter driver, you should measure 91 dB of
sound pressure when standing 1 meter from the face of the driver and giving
the speaker 1 watt of pink noise input.  This figure is usefull in determining
the output of the driver at any power level.  Every time you double the 
amount of power in, you should get 3 dB more out of the driver.  So with this
91 dB @ 1 watt and 1 meter driver, if you put in 2 watts you should get 94 dB,
4 watts => 97 dB, 8 watts => 100 dB, etc.  Every time you give a driver 10
times the power, you get 10 more dB out.  With the same driver:  1 watt => 91 dB
10 watts => 101 dB, 100 watts => 111 dB, 1000 watts => (probably destroys
the driver but maybe gives you 121 dB).

As long as I'm covering this, I should mention that every time you double
your distance from the driver you LOSE 6 dB.  Conversely, if you halve your
distance from the driver you should gain 6 dB.  Example:  with the same driver
as above with 1 watt input:  1 meter => 91 dB, 1/2 meter => 97 dB, 
2 meters => 85 dB, 4 meters => 79 dB, etc.

Newsgroups: rec.audio.car
From: jbhuber@iastate.edu (Joseph B Huber)
Subject: Portable CD player in car
Organization: Iowa State University, Ames, IA
Date: Sat, 19 Dec 1992 23:42:47 GMT

Has anyone solved the noise problems that occur when the output from a
portable CD player powered by DC-DC converter is played through the car stereo
amplifier?

This thread was discussed a few weeks ago, but I don't believe anyone mentioned
a working solution. I apologize if I missed it.

Over Christmas break, I will have an opportunity to work on my car in a HEATED
shop, and this is one of the problems I want to work on.

Thanks.
-- 
Joe Huber 
(jbhuber@iastate.edu)        | Capt. James T. Kirk on the 2nd law of thermo: 
Dept. of Mech. Egr.          |  "It's not a hundred percent efficient,
Iowa State University        |   but nothing ever is."
From: bell@hops.larc.nasa.gov (John Bell)
Newsgroups: rec.audio.car
Subject: Orion telephone number?
Date: 15 Dec 1992 16:18:28 GMT
Organization: NASA Langley Research Center
Distribution: world
NNTP-Posting-Host: hops.larc.nasa.gov
Keywords: Orion

The subject says it all. Does anyone know the telephone number for Orion? Or,
does anyone know of any other place where I can get a service manual for an
Orion 250SX?

Thanks in advance!

-----
John Bell
NASA Langley Research Center
bell@hops.larc.nasa.gov
From: eddys@citrus.SAC.CA.US ( Steve Eddy )
Newsgroups: rec.audio.car
Subject: Re: Class A MOSFET Power Amp for sale...
Date: 19 Dec 92 22:46:03 GMT
Organization: Citrus Grove Public Access ( 916 ) 381-5822    Sacramento CA.  USA
X-Newsreader: Tin 1.1 PL4

jreiser@scott.skidmore.edu (Jason Reiser... Asleep) writes:
: 
: Class A in a car is not possible in an output stage from what I have
: read... still looking for the source, though I suspect Autosound 2000.
: As for tubes, Milbert introduced their BaM-230 about 4.5 years ago.
: It is a $2000 (list) 30 watt per side tube amp using 6JN6 output
: tubes.  The problem with tubes in autosound had to do with the high
: voltage needed to drive them, but this baby is supposed take care of
: the problems with an impressive p/s.  I'd love to get my hands on one!
: 
: 				- Jason
: -- 
 
   Class-A not possible in a car? I must not have read that part. Glad I
didn't, too, or else I wouldn't have built a class-A amplifier for car audio
:)

se

-- 

# Where no man has gone before.                   eddys@citrus.SAC.CA.US
#   *default* .sig file                      csusac.ecs.csus.edu!citrus!eddys
# The undiscovered land.                                   /\../\
Organization: Sophomore, Mechanical Engineering, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.audio.car
Date: Fri, 11 Dec 1992 22:07:21 -0500 
From: Steve Anthony Nilsen <sn1k+@andrew.cmu.edu>
Subject: Fix scratch in CD?

I have just a small nick in a favorite CD that causes my car CD player to
mistrack one certain song.  The CD plays fine in home CD players, but it's
enough to confuse the one in my car.  Is there any way to slightly polish
this out?  It always mistracks about 50 seconds into the song and takes
like 20 more to get past the scratch unless I cue it ahead.  The nick is really
small, like the size of a fingernail clipping.  Is there something I can use to
fill it slightly?

Steve
Newsgroups: rec.audio.car