This has been a source of debate on this NG for some time now, and I
have been part of it.

The Gospel of Live Sound, as inscribed in stone by Moses and handed
down since the time of Christ, mandates "Thou Shalt never operateth
Power Amps at less than Settingus Maximus". That is, amp knobs full
out maxed.

As I stated before, if I operated my Church mixer at unity(levels peak
betw. 0dB and +3dB) AND kept the amps wide open, the noise and
feedback alone would keep satan from that place(!) not to mention
DEAFEN the entire congregation, band, and Pastor. Even 33 bands of EQ
notching out both the stage monitors and the house would not help the
fb; our facility is simply too small.

Currently we are running, at 4ohms, 375Watts per monitor to our stage,
and 390W to each main(a Mackie 15"woofer/horn tweeter variety). This
is more than enough power for our sanctuary(60ft deep, 30ft wide, 9ft
acoustitile ceiling) capacity 110.
Mains elevated so that tweeters are 8' above floor.

All I ask is: To reap the benefit of "extra headroom" of running the
amps full out, where and what in my gain structure should I adjust?

Thanks,

ChrisCoaster
CC


Power amps at max is usually not right.


Adjust the input trims so that the peak lights come on rarely (if ever), your
channel faders will be at 40-80% of their scale and the master faders are at
75% of scale. This gives you room to adjust signal where the fadert has the
best resolution.

Then adjust your power amps so that they provide the desired SPL's for your
church.

This will keep the noise floor of the board down and will provide your board
with the output necessary for your documentation recorders.

The attenuator on the power amp does not control power, it is only sensitivity
of the amp that is changed.

If you are running an entire system at full capacity you still may not want the
power amp max'ed.
For the most headroom (where there isn't going to be any) the board, eq and
power amps should reach clipping at the same time, then run it a couple of dB's
less.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty

(Richard Kuschel) wrote in message

Power amps at max is usually not right.


Adjust the input trims so that the peak lights come on rarely (if ever), your
channel faders will be at 40-80% of their scale and the master faders are at
75% of scale. This gives you room to adjust signal where the fadert has the
best resolution.

Then adjust your power amps so that they provide the desired SPL's for your
church.

This will keep the noise floor of the board down and will provide your board
with the output necessary for your documentation recorders.

The attenuator on the power amp does not control power, it is only sensitivity
of the amp that is changed.

If you are running an entire system at full capacity you still may not want the
power amp max'ed.
For the most headroom (where there isn't going to be any) the board, eq and
power amps should reach clipping at the same time, then run it a couple of dB's
less.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty
_____________________________
But Rich, Mike, I thought that maxxed amp volumes was inviolate P.A.
Gospel. That doesn't mean I agree with it, but every live sound
person I know swears by it!

I'm glad to see a couple folks in my court on this issue. : )

-ChrisCoaster

"ChrisCoaster" wrote in message
om...
(Richard Kuschel) wrote in message

Power amps at max is usually not right.


Adjust the input trims so that the peak lights come on rarely (if ever),
your
channel faders will be at 40-80% of their scale and the master faders
are at
75% of scale. This gives you room to adjust signal where the fadert has
the
best resolution.

Then adjust your power amps so that they provide the desired SPL's for
your
church.

This will keep the noise floor of the board down and will provide your
board
with the output necessary for your documentation recorders.

The attenuator on the power amp does not control power, it is only
sensitivity
of the amp that is changed.

If you are running an entire system at full capacity you still may not
want the
power amp max'ed.
For the most headroom (where there isn't going to be any) the board,
eq and
power amps should reach clipping at the same time, then run it a couple
of dB's
less.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty
_____________________________
But Rich, Mike, I thought that maxxed amp volumes was inviolate P.A.
Gospel. That doesn't mean I agree with it, but every live sound
person I know swears by it!


Do they run big name groups? Every sound consultant/contractor swears AT
that! Check with the manufacturer on how to set up the gains. They all
agree to NOT run an amp at max. In fact most pros run an amp rated at 1.5
to 2 times the watt rating of the speaker(s). What will happen when you run
that amp at max? What will happen when a speaker is rated at 300 watts and
the amp is rated at 450 to 600 adn you max it out?

--
Mike D.

www.stopassaultnow.org

Remove .spamnot to respond by email


I'm glad to see a couple folks in my court on this issue. : )

-ChrisCoaster


---
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"Mike Dobony" conveyed the
...

Do they run big name groups? Every sound consultant/contractor swears AT
that! Check with the manufacturer on how to set up the gains. They all
agree to NOT run an amp at max. In fact most pros run an amp rated at 1.5
to 2 times the watt rating of the speaker(s). What will happen when you run
that amp at max? What will happen when a speaker is rated at 300 watts and
the amp is rated at 450 to 600 adn you max it out?

--
Mike D.

www.stopassaultnow.org
_________________________
I don't think I'd want to to be around to find out(!)

Seriously though, I'm NOT arguing with you - I'm simply reporting back
here what I've heard from self-ascribed "experts" in the field.

My only concern is I hope the three of us here don't get flamed,
because some of those "experts" may be lurking here.

Take care,

ChrisCoaster

Do they run big name groups? Every sound consultant/contractor swears AT
that! Check with the manufacturer on how to set up the gains. They all
agree to NOT run an amp at max. In fact most pros run an amp rated at 1.5
to 2 times the watt rating of the speaker(s). What will happen when you
run
that amp at max? What will happen when a speaker is rated at 300 watts
and
the amp is rated at 450 to 600 adn you max it out?

--
Mike D.


Probably nothing bad will happen as long as you don't clip the system.

An amp of double the power rating of a speaker is safer than an amp at the
power rating of the speaker being clipped.

I regularly use amplifiers with 300 watt ratings on 80 watt speakers. i just
don't clip them.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty

in article , Richard Kuschel at
wrote on 9/15/03 13.36:

Do they run big name groups? Every sound consultant/contractor swears AT
that! Check with the manufacturer on how to set up the gains. They all
agree to NOT run an amp at max. In fact most pros run an amp rated at 1.5
to 2 times the watt rating of the speaker(s). What will happen when you
run
that amp at max? What will happen when a speaker is rated at 300 watts
and
the amp is rated at 450 to 600 adn you max it out?

--
Mike D.


Probably nothing bad will happen as long as you don't clip the system.

An amp of double the power rating of a speaker is safer than an amp at the
power rating of the speaker being clipped.

I regularly use amplifiers with 300 watt ratings on 80 watt speakers. i just
don't clip them.
Richard H. Kuschel
"I canna change the law of physics."-----Scotty


You're always more likely to destory a speaker by underpowering it rather
then overpowering... One of the first rules about audio I was taught.

J


--
josh.snider
cave.productions
416.524.6927

ChrisCoaster wrote:
Uh oh, sounds like we may have a "Max Knobs" defense brewing here...

-CC

I guess neither the advice you've gotten on this thread nor the email I sent you
was what you wanted to hear.

Steve O'Neill wrote in message ...
ChrisCoaster wrote:
Uh oh, sounds like we may have a "Max Knobs" defense brewing here...

-CC

I guess neither the advice you've gotten on this thread nor the email I sent you
was what you wanted to hear.
____________________
Both assumptions are wrong and are just that - assumptions.

Except for the last two posts(Richard's and Josh's), everything I've
heard here is in line with my instincts and rings of common sense with
regards to running power amps. The tone of Richard and Josh's posts
seem to impress me as hinting at running the amp gains full out, thus
my "Max Knobs" rebuttal.

Please send me your e-mail again as my service drops messages from
time to time and I may not have gotten it.

regards and apologies for any misunderstandings,

-ChrisCoaster