This came to my email. The post originated in RAC. I prefer to reply here as
well,
there are others that can help to answer and debunk the audio myths better
than I.

----- Original Message -----
From: "Les" <soundfreak03@sbcglobal.net>
Newsgroups: rec.audio.car
Sent: Wednesday, May 19, 2004 6:30 PM
Subject: Re: System I'm designing - two questions

message

ancient..

amplifier with a

BTW- Most supposed "audiophiles" usually say that >200 is enough.

moot point nowadays

number.

"with higher frequencies, thats true, its not largely
  noticeable at
comfortable hearing levels, but with lower frequncies, it
is a drastically
noticeable difference. amps with much higher damping
factors have MUCH
better control of the woofers. I thought the same as you,
until I tested it
for myself last year, comparing side by side, US amps
DE-3000, and the
USA-3000 , both setup with the same head unit(pre-outs had
low-pass set to
100 Hz, all crossovers and subsonic filters disabled on the
amps, wired to
the same subwoofer configuration, 3000x1 watts @ 2 ohms,
and the gains were
adjusted on both amps until they outputed 130 dB at 40 Hz,
for testing
purposes. I tried to eliminate any varibles other than the
amps themselves..
anyways, the results were as follows: the DE-3000
(advertised damping factor
of >200) did NOT have NEARLY the amount of woofer control
that the USA-3000
(advertised damping factor of >2200),  there was an amazing
difference in
woofer "tightness" and control, not really noticeable so
much when you'd
play straight test frequencies through it, but once it was
set, playing
highly bass reactive music through it, like speed metal and
various rap
tunes. anyways."

Let me see your data. Where are your measurments? It sounds like you relied
solely on looking at the woofer and listening. Both "tests" which don't hold
any water. It is the same snakeoil techniques that marketing people use to
get people to believe the myths anyway. You attempted to make your tests
valid, but without data and measurements it was all for not.

"the engineers over at US AMPS told me on
the phone it was
because of the high damping factor, and i choose to believe
them, since
thats what they went to college for."

You just called up US Amps and talked to the engineers? It seems highly
unlikely. Especially since if they knew what they were doing they would have
told you the truth about damping factor. I did some more research on damping
factors and relation to SQ. Here are some of my results. I found conflicting
websites, as I expected, and I noted one large difference between the 2
arguments. Those that are claiming the big SQ differences often had no data,
other than the type of "evidence" you provided, the rare couple that did had
virtually no explanation of how the numbers were acheived. Those that are
saying that the big number DFs were really meaningless usually provided
numbers, with explanations of how they are achieved, and most showed how it
actually related to the speaker. Which how it actually relates to the
speaker is important, and from what I have seen is overlooked by the Big
number DF camp. Naturally I could find sites that are the other way, this is
just generally what I found. (Yahoo search for "damping factor")

Here is a few articles.
http://www.trueaudio.com/post_013.htm

http://66.218.71.225/search/cache?p=damping+factor&ei=UTF-8&cop=mss&u=www.diyspe
akers.net/Articles/Richard%2520Pierce%2520DAMPING%2520FACTOR.pdf&w=damping+facto
r&d=EE886B7D51&c=524&yc=10240&icp=1

http://otlamp.com/articles/tomcik/

This is one of those, that is kinda right, but never provides any basis for
the numbers achieved.
http://www.leecao.com/caraudio/amplifier.html

Now, a marketing blurb from my favorite pro sound amp company. (Notice no
data, only touting thier amps) I found that most amp manufactures claimed
that big number DFs are important, but most are like Crown and never provide
any hard data.
http://www.crownaudio.com/pdf/amps/136224.pdf

it doesnt
advertise

enough rating and

they sounded too

unit. you want
good

that will argue
with

profile"
Farenheit

produced better
SQ

get sh.t for
this!)

quantum amps( Q 175-2

distorted more at

perhaps it will help

"ohhh i dont know, different quality of crafstsmanship?
different quality of
components? different designs? they just sound different
bro."

They just sound different?? I don't think so.

"Ever compare a
tube amp to a solid state amp side by side? HUGELY
different sound. They
will look almost identical on an oscilloscope if adjusted
right, but they
will still each have a distinct sound."

Sorry, I really meant SS amps. I forget to mention that, but since >99% of
car amps are SS I thought it was an assumed.
There is also more than an Oscope. And Tube amps and SS amps usually do not
have thier specs within the threshold of human hearing.

When you measure then,

differences below
the

different?

"i dont know, you tell me, since you seem to have all the
answers,"

They don't. That is the answer. If you cannot measure a difference then how
can you hear it?? Some mythical fairy just makes amps sound different?

" go by
what my ears tell me.. Sure, if you had a 50 band EQ
attached to every amp
setup  to get them to sound EXACTLY the same at a given
volume level, then
yes, id agree with you.."

That's the point. You don't need a 50 band EQ. Level match them, operate
them within their linear limits, then measure them. The differences, if any,
would be below the threshold of human hearing. The human ear is a remarkable
ineffiencient and inaccurate device. The point of the amps sound the same
argument for me is this, there are more important things to base a purchase
of an amp on.

clipping, then
you

car.

"this is absolute nonesense..there's always differences that
are audible in
every audio setup..otherwise ALL quality amps would cost
the same because
there was no real difference between them, and there woudl
be no need for
audio competition."

Sure there a differnces in every audio setup. I never said there were not.
Amps don't cost the same because of several factors, not just the supposed
SQ. You are forgetting to price in quality, output power, features, and even
reputation. There are SEVERAL factors into determining the cost of an amp.
Your argument is becoming absurd.

Your ESX

clipping it or it

"nope, they were fine.. i had 4 of the same amp.. all
soudned the same."

Then you were clipping it, or possibly hearing something that wasn't there.

A softer sound is often associated with a lower volume. The

the same, the I
heard

"ummm, what else would you have to go by except what you
hear?"

Of course, the ultimate goal of a car audio system is to sound good to you.
But when you realize that there are not SQ differences in your amps it
allows you to focus your search on important features to make sure you get
the best amp for your situation. Then you can spend the money you saved by
not purchasing that "SQ" amp and buy those speakers that you really liked.

"and the
physics DO support that amps will sound different. These
amps dont all share
the exact same componenets, do they? HIGHLY doubtful."

They don't have to use the same components. Components can go into the
quality of the amp, but not really the SQ. Your logic is flawed. Physics
tells us that if we cannot measure the differences then HOW can we hear a
difference? There are not differences to hear. If there is nothing to hear,
then there is nothing to hear. Does that not make sense? Once someone from
the "amps sound different" camp can come up with something besides "I heard
it" or "They just does" then I might listen, for about a minute.

Les