Gain Controls?

[TC Entertainments 0]

Hi guys,

 

I've got a new mixeramp, well it's an old one but haven't got round to having it repaired for a couple of years.

 

Please see the pic I've uploaded to http://tc5712.tripod.com/tcentertainments/id3.html

 

Sorry it's a bit big!

 

As you can see I have a gain control on the stereo channel I use (1), seperate gain controls for amp a & b (2) (this model has seperate amps for let/right) and then the usual master volume slider (3).

 

I take it that it's a given that the master volume slider is my main focus but what would you recommend I have the stereo & amp gain controls set to?

 

Cheers.

[diy_disco 0]

i tend to turn my amps onto full

 

then the gains in the middle

 

then control the overall level by the master slider

 

i tend to put each channel to the top when in use and adjust the volumes with the gains

[TC Entertainments 0]

i tend to turn my amps onto full

 

then the gains in the middle

 

then control the overall level by the master slider

 

i tend to put each channel to the top when in use and adjust the volumes with the gains

 

Thanks diy,

 

I'm sure that's what I used to do but the first couple of outings with it I've tried to keep everything 'halfway' for some reason?

 

Does anyone know if one way or the other causes more or less stress on the unit?

 

Cheers,

 

TC

[superstardeejay 0]

OK there is a right way and a wrong way to this!

 

The individual channel gains are important. If they are too high, you risk clipping the input even though the amp section is turned down.

 

You set them by playing the music/cd etc through the channel in question, pressing the PFL button and setting the gain so the VU meter peaks ay 0dB during the loudest passages. This usually happens when the gain pot is pointing to the 0dB mark if for example you are using the line input; there will be an additional scale for mic inputs. Your VU meter assigns the right column of LEDs to the PFL bus when it's selected.

 

The PFL level is affected by the channel EQ pots as well, so set the PFL level after you've adjusted the EQ to taste. This level indicated on the PFL meter is then the level that the master & effects bus will see when the channel fader is pushed up to the 0dB level.

 

Bear in mind the master bus also accepts the FX and aux return levels as well, so if they're in use, you'll need to adjust the master once the FX and any outboard sends are brought into the mix.

 

You can use the amp levels as an overall top limit, such that with the amp levels all the way up, the amp is going to be running flat out when the (non pfl selected) output VUs are in the 0db range, in your case the first yellow LEDs.

 

The main thing is to remember that the VU meter is an indication of mixer level, not amp level. But your clip leds are driven from the amp section, these should never flash if the master VU is not allowed to peak.

 

As you can see, a PA desk is a little more involved than a DJ mixer!

 

[TC Entertainments 0]

Wow!

 

Thanks superstar,

 

I always leave the PFL buttons on for the channels I'm using just to keep an eye on what (I thought) was amp load and then adjusted the gain controls willy nilly through the night as needed!

 

In my local pub senarios it wouldn't be best welcomed if I started testing my max output levels while setting up early in the evening, is that what you're advising?

 

Sorry if I'm being stupid and missunderstood!

 

Cheers,

 

TC

 

 

[superstardeejay 0]

Yes, if it's recorded music, no need to fiddle with the gains once they're set for the devices plugged in; thats what the channel faders are for. Of course they might need a slight tweak if one CD is recorded vastly quieter or louder than another; but this is a CD quality issue isnt it! Bit more difficult to do it with mics without doing a sound check but there you can just use the PFL level in conjunction with your ear and to make sure nothing peaks out if anyone shouts; use it then to 'level' between different makes of mic so the physical channel fader positions bear a useful relationship to each other. It's all about making it easier to set a mix using your eyes as well as your ears. It's more important when you have many channels to mix together for a band or theatre etc.

 

PFL stands for 'Pre Fade Listen' and is similar to 'cue' on a DJ mixer so the right VU meter displays the level before rather than after the channel fader. If you have headphones, the channel with PFL buttons pressed will appear in them.

 

You dont actually need the amp to be working at all to basically set the levels with PFL.

 

Once the PFL levels are set, cancel all the PFL buttons so the VU meter reverts automatically to mixer output level. That is the accurate way of judging amp load.

Some mixers (not yours I dont think) have a flashing PFL light by the main VU meter to remind you you've left one or more PFL buttons in.

 

 

Edited March 30, 2011 by superstardeejay