On Fri, 28 May 2004 16:01:45 GMT, Eddie Runner
wrote:

Scott Gardner wrote:

Once you have all of the individual gains set correctly, and you're
trying to balance the relative speaker volumes against each other, I
would change the text to explicity state that you should always make
the adjustments by LOWERING the gain on the speakers that are too
loud, never by raising the gain for the speakers that are too soft.

Its pretty common that I do it the way you say NOT TO....

I sometimes get ALL the gains OFF so there is no sound
and then set something (like the subs) as a reference point, and
then bring the fronts and backs up till the listener hears them...

So I guess I prefer to do it the way you say NOT to do it...

I got a pretty good track record in the last 30 years... wonder how
many 1000s and 1000s of cars I have done that way..??

I would still re-word the last paragraph about adjusting gains in a
multi-amp system. If a reader were to follow the directions in your
paper word-for-word, he'd set the head unit to 75%, and adjust all of
the amps so that they're being driven to full clean volume. So far so
good.

At this point, let's say he notices that his front component speakers
aren't loud enough relative to the subwoofers. Since all you say in
your paper is to "make the adjustments to the amplifiers so the levels
are the same", he might be tempted to just increase the gain on the
amp that's powering the component speakers. If he increases it very
much at all, he's going to be clipping his component amp, since it was
already being driven to max volume from when he adjusted all the amp
gains earlier in the procedure.

The smarter thing to do would be for him to lower the gain on the
subwoofer amp instead to bring the relative volumes into balance.
This will give him the maximum overall volume out of the system while
keeping all the levels correct relative to one another, and not
causing any of the amps to clip with the head volume at 75%.

It probably seems obvious to you since you've been doing this for so
long, but I just though it was worth mentioning since someone with
little or no experience might be using your paper as a guide to set up
his system.

Scott Gardner

Scott Gardner wrote:

I never said to maximize the volume contol, chuckles - I said to
maximize the usable volume swing.

like ALL THE WAY UP..??
if thats not what you mean then EXPLAIN IT!

Scott Gardner wrote:

What happens if the sub amp (to use your example) is much more
powerful than the other amps in the system? After you've set the subs
to whatever level you like, now you have to raise the other amps'
gains up to balance the other speakers' outputs with the subs' output.
If the other amps are significantly less powerful, you could end up
clipping them before they reached an appropriate volume relative to
the subs. Now you have to lower the sub amp's gain and begin again.

I set the amps so they are the same sound level to the listener. or the
sound level that sounds best to the listener...

If 1 amp is 10000watts and 1 amp is 40 watts, that would probably
be a really BAD BAD DESIGN, but I would set the amps up so they
sounded good together...Balanced.. Equal to the listener.... Some folks
might like a little more bass or a little more outta the back or front
speakers,
I would set it up so it sounded good to em...

BUT, if you turn it up it would be obvious that the 40 watt amp would
clip way before the 10,000 watt amp... So IF the user wanted to exceed
the point where the weaker amp clips, I would certainly NOT CHANGE
the gain structure, instead I would suggest a better system design for
the user....

Do you in some way want to modify when the amps clip???
If so, by doing that would really make the system sound
unbalanced and BAD.....



Eddie Runner

On Fri, 28 May 2004 21:30:11 GMT, Eddie Runner
wrote:

Scott Gardner wrote:

I never said to maximize the volume contol, chuckles - I said to
maximize the usable volume swing.

like ALL THE WAY UP..??
if thats not what you mean then EXPLAIN IT!


Since a distorted output from a head unit has never been a problem for
you, don't worry about it. What I meant by "maximizing the usable
volume swing" is to choose a "set point" for the head unit while I set
the amp gains such that I maximize the range that you can turn the
volume knob without the deck output distorting OR the downstream
amplifier clipping. Note that after all of the adjustments are done,
it WILL still be possible to clip the downstream amp, simply by
turning the head volume past the "set point" that I used while setting
the amp gains.

In theory, if I never heard the head unit distort, my "set point"
would be 100% on the head unit's volume knob. Normally, this would
mean that you might not be able to get full volume from the amplifiers
while playing a soft recording. However, the songs I'm playing while
adjusting the gains were recorded at -6 dB, which is very soft. This
extra 3 dB of attenuation gives the "wiggle room" necessary to ensure
that the user will always be able to drive the amps to full volume,
unless they're playing a song that was recorded ridiculously low, like
-12 dB.

Like I said, since distortion from the head unit has never been a
problem for you, you can ignore that whole part of my post and just
use 75% for the head unit "set point" volume like you recommend in
your paper.

Scott Gardner

On Fri, 28 May 2004 22:00:10 GMT, Eddie Runner
wrote:

Scott Gardner wrote:

What happens if the sub amp (to use your example) is much more
powerful than the other amps in the system? After you've set the subs
to whatever level you like, now you have to raise the other amps'
gains up to balance the other speakers' outputs with the subs' output.
If the other amps are significantly less powerful, you could end up
clipping them before they reached an appropriate volume relative to
the subs. Now you have to lower the sub amp's gain and begin again.

I set the amps so they are the same sound level to the listener. or the
sound level that sounds best to the listener...

If 1 amp is 10000watts and 1 amp is 40 watts, that would probably
be a really BAD BAD DESIGN, but I would set the amps up so they
sounded good together...Balanced.. Equal to the listener.... Some folks
might like a little more bass or a little more outta the back or front
speakers,
I would set it up so it sounded good to em...

BUT, if you turn it up it would be obvious that the 40 watt amp would
clip way before the 10,000 watt amp... So IF the user wanted to exceed
the point where the weaker amp clips, I would certainly NOT CHANGE
the gain structure, instead I would suggest a better system design for
the user....

Do you in some way want to modify when the amps clip???
If so, by doing that would really make the system sound
unbalanced and BAD.....



Eddie Runner


I agree that having one amp that could overwhelm the other amps in the
system isn't a good design, but some people don't buy all new
equipment at once, so temporary mismatches often occur. I'm sure
you've seen a lot of this in your shop.

When I'm dealing with one amp that can easily overwhelm the others, I
set up the gains so that when the weaker amp is being driven to max
volume, the stronger amp is only putting out just enough power for the
overall system to sound balanced.

The way I get there is by initially setting the gains on both amps so
that they're being driven to max volume when the head unit is at 75%
(or whatever set point I use). At this point, I now have an
unbalanced system, with the stronger amp overpowering the weaker amp.
To bring the system into balance, I can either increase the gain on
the weaker amp or reduce the gain on the stronger amp. Obviously,
reducing the gain on the stronger amp is the way to go.

When I'm done, the amps will be balanced. For a given input from the
head unit, I'll be using a lot more of the smaller amp's potential
power output, and less of the stronger amp's potentialpower output,
but with mismatched amps, that's what's going to have to happen.

Scott Gardner