Another Gain structure question. What do I turn down.?

Fanman20

Greetings Guys

If have been enjoying following your forum, very informative.
I have completed your suggestion, both in the manual and in this forum, in setting up my gain structure.
Makes sense and understand the concept
But the system I am using is about 3 times loader than I need, so when I put a mic / CD etc though the system what \"level\" should I turn down to run the system at a comfortable SPL?

1 Amps
2 Driverack PA
3 Main desk output
4 Channel fader
5 Channel gain

I am guessing amps
Thanks Mark

Dra

Excellent question, but loaded, somewhat.

\"Unity\" is the goal.

I \"lean\" towards amps - You'll have to re-calibrate the balance (not a big deal), but you'll find that your AFS (feedback) system will work faster with the signal hot and the amps cool (down). The problem here is IF you need more volume DURING a gig, that can be a major oops.


DRA

Gadget

Unity is A goal but not THE goal... Unity gain means that if we start with 1 volt at the input of the first device we should still be at 1 volt at the amps... theoretically...The goal of the Gain structure is to get all the equipment working in their optimum voltage range...that is to say they are all speaking the same electrical language, and running in their optimum range. Getting the best signal to noise ratio in the analog sections is the number one priority, the individual channels become most important to signal to noise, especially when using a number of channels in the case of live sound, certainly less of a problem for DJ..and Karaoke where 2-3 channels are in use.

As Dra pointed out even though you don't need the extra headroom, it's nice to have it when it's needed so my vote is for the master faders. I do this all the time since I need to start out the night quieter, even at the expense of FOH sound where the monitors are clearly loud enough to affect the mix and make it less intelligible. It's a fact of life I have to deal with. The owner is more afraid of loosing customers to loud sound as opposed to less than optimum sound. It's nearly impossible to tell a band \"give me your quietest stage volume for the first set\" and get it and the rest of the night right. So for the first set it usually is a struggle to get the sound set for later, then turn down a bit... the only logical place is the master faders (in the case of the DRPA especially with no remote capability) Even with the master faders on the 260 available for this purpose they are not ganged together and so each channel would need to be set separately.. not good... So master faders it is.

My system is dead quiet running KILL volume.. and dead quiet with the master faders down, so there isn't really any reason to not do it this way.. at least for me.

Cheers mate!
G

Dra

I can't prove it, but I actually started a post that went at noise levels and Masters. Like Gadget says, every situation warrants a different approach to get the best sound application. Good luck and let us know which way you go and how it goes when you get there.

DRA

Fanman20

Thanks for your thought
I like both thoughts so I might I use both ideas
set the master fader down maybe 15 db, turn the amps up to \"working level\"
This gives me the head room Gadget was mentioning.
Where is Kevin thoughts?

I am helping a church out with this problem at the moment
They have 5 out of 13 channel lights peaking. Channel faders up about a 1/3. Master fader up about a 1/3. DR 260 how nows where and amps up about 1/2
Fold back channel send on about 2 foldback masters on about 2 and amps nealy full

I have to start from scratch so like to get it right

they heve a 260
Thats the good news
I own a DRPA
thats the bad news

Dra

The correct # of channel input lights clipping is -0-.

DRA

Fanman20

Thats new information to me. Did not know that (thought it was something like +6 db)

Thanks

I tend to run desks just below when the clipping light comes on
If the clipping light comes on I turn the channel gain down a bit

Mark

Gadget

On the mixer, if you have PFL to the output meters (when the PFL button is depressed the master output meter... one of them... becomes a channel meter. This allows you to view in better detail the level on that channel.. Now set the channel fader to unity-0- and set the input gain so that the input signal peaks no more than 30% above -0- vu.This insures no channel clipping and plenty of headroom.

The input channels on the mixer are the worst place other than the DR to have clipping. If you don't have PFL meters, find the channel clip point and turn the input gain control down about 10-12 db. So, if your mixer has +22 input capability like the Mackie VLZ mixers you will have 10-12 DB of headroom, If you want more just be sure your at least averaging about +3 over -0-vu.

Gadget

Fanman20

Thanks guys

I have tried the \"Master fader down 5 db and amps up about 1/3\" thought
This has worked well by giving a little headroom at the masters.
and the amp on 1/3 gave me the volume I needed in the room
Liked that way of setting up the mixer

Gadet wrote
On the mixer, if you have PFL to the output meters (when the PFL button is depressed the master output meter... one of them... becomes a channel meter. This allows you to view in better detail the level on that channel.. Now set the channel fader to unity-0- and set the input gain so that the input signal peaks no more than 30% above -0- vu.This insures no channel clipping and plenty of headroom.

I agree with that concept but then you need to turn the channel fader down? leaving the fader at about - 10db??

I like to run a desk a \"o\" db on faders so when I have to turn all faders down I know where to put them back to. (old age makes me forget where they were)

How do other set up their desks??
Mark