Re: Help: How to set gain leve?? - oldroadie - Pro Audio Asylum

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Re: Help: How to set gain leve??

In Reply to: Help: How to set gain leve?? posted by cktc on December 15, 2004 at 11:19:51:

My thinking
Gain structure starts at the mixer. I want as much output from the mixer as possible without distortion.
"Eyeballing the gain structure will get you close with simple tools, using a Volt meter or better yet a scope will get you a lot better setting.
First, turn the amp off.
1. Set mixer to max undistorted out.
Run some recorded pink noise into a channel EQ flat on channel (all at 0). Watching input meters peak the channel out with the top gain control, then back off until the red light just doesn't light anymore. Channel now has maximum input before distortion for this signal.
Turn this channel fader up to 0db on the board. Turn the master faders up and watch the meters. Get the master output to run just under the red (usually +12 or +14 on most boards).
2. Set EQ to match mixer.
With amp still off (I hope) flatten EQ on all inputs. Adjust the input of the EQ until the levels on the board match the levels of the eq.
Do the same for any limiter, compressor, or crossover that you have connected after the EQ.
3. Set amp gain.
Amp still off, unplug speakers. Turn gain controls down. Turn gain controls up until red light hits, back off gain a hair. Mark this location on your amps or commit to memory.
You now have the maximum signal to noise for this system. Use a scope an measure waveform outputs at each stage to get the best results.
Now turn the ammp down, then off.
Get the vocal mic. Talk into the channel, and gain the mic signal to hit about +9 on the input once again, flatten the EQ. Set the board outputs master to about -3 set the channel fader to 0. Turn on the amp. Without touching the board, talk into the mic and turn the gain up on the amps until it's plenty loud, or you get a squeal. Notch the squeal out with the eq, and turn the amp up some more until you have the loudness you want or you've notched the EQ so much there's really no audio left in the system.
Mics should always be behind speakers. Esecially if people whisper into the mic.

Tom

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Follow Ups Full Thread

Topic - Help: How to set gain leve?? - cktc 11:19:51 12/15/04 (12)

gain structure and ringing out the system - DJ's Later 05:59:03 01/07/05 (1)

Re: gain structure and ringing out the system - Servojohn 10:13:31 01/08/05 (0)

Re: Help: How to set gain leve?? - servojohn 19:49:00 12/18/04 (1)

Re: Help: How to set gain leve?? - oldroadie 16:34:18 12/19/04 (0)

Re: Help: How to set gain leve?? - oldroadie 17:43:54 12/17/04 (0)

here is a site on that subject - Ray Kimber 11:03:00 12/16/04 (0)

Re: Help: How to set gain leve?? - STUART 07:19:03 12/16/04 (0)

Re: Help: How to set gain leve?? - Jim York 12:02:04 12/15/04 (4)

Re: Help: How to set gain leve?? - Bob Lee (QSC) 14:31:40 12/15/04 (0)

Re: Help: How to set gain leve?? - cktc 13:52:04 12/15/04 (2)

Re: Help: How to set gain leve?? - Bill Fitzmaurice 15:50:19 12/15/04 (1)

Re: Help: How to set gain level?? - Bob Lee (QSC) 08:36:21 12/16/04 (0)

Follow Ups

Re: Help: How to set gain leve?? - oldroadie 17:43:54 12/17/04 (0)

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