Mixing techniques?

[Mark Finley]

I'm having a friendly debate with a member of the crew. He's been taught that when you run the mixer, all of the sliders should be in the zero position if at all possible, and you control the volume with the gain knobs.

I say you use the gain knobs to regulate signal strength, and after you have a healthy signal, you then use the sliders to control volume, even if that ends up with a silder that is at -30db.

Is one way of doing it considered "old school"? He's almost twice my age and a good friend, so I want to handle this diplomatically. When one person gets up there and starts adjusting it one way, and EVERYBODY else on the crew does it the other way, it can take half of the next ensemble practice to get everythign back where it should be.

[Lee Ann]

Personally I use a combination of both techniques (so I didn't vote on the poll). I do like to set the gain control so that the faders are near zero position if possible. During the actual service I mainly use the faders to tweak someone's volume if needed, but there are a few of our vocalists that really get "into" it and I end up pulling back their gain.

[sstanton]

One of the big reasons people mix with the gain knobs is so the pre-fader monitors get changed as well as the house. I would say it is more of an old school way of thinking, but I've run into those who are fresh out of "sound tech" school who do it too.

Personally I set the gain for the best range on the fader (usually so at rehearsal it is near 0) then mix with the faders. I only grab the gain if I cannot get enough level with the fader. If it's a mic that is going to have many different voices on it, I run it post-fader in the monitors so I am not adjusting 5 knobs for each person who uses it.

As a matter of etiquette when I run someone else's system I try to make as little changes as possible to their board, cause I wouldn't want to reset my entire board because someone else ran it, I'd be furious.

I think the best thing is to explain to him that this is how we mix here, and that him changing everything causes havoc for the rest of the sound crew, it's not that his way is wrong just different, ask him to please respect the way they mixing is done here.

[dmot]

Originally Posted by Lee Ann

Personally I use a combination of both techniques (so I didn't vote on the poll). I do like to set the gain control so that the faders are near zero position if possible. During the actual service I mainly use the faders to tweak someone's volume if needed, but there are a few of our vocalists that really get "into" it and I end up pulling back their gain.

Hopefully, we will get someone to comment who knows for sure but what Lee Ann said is what I have been taught in a couple of seminars (not schools but two day seminar type things). I was told that gain structure should be set at unity for the best possible use of the boards ability to process the signal. They (seminar leaders) got really worked up about this and they seemed to feel that the majority of sound boards were not run properly as far as gain structure was concerned. Again, hopefully someone who actually knows for sure will comment here.

[Mark Finley]

But wouldn't gain at unity mean that all incoming signals have similar signal strength, and then you use the sliders for output volume?
for me gain=input, and sliders=output

I agree with unity of gain, but not unity of sliders.

[kerwin kanago]

Board designers work to have zero on the slider be the "optimum" spot for overhead vs signal-to-noise ratio. So it's best to set the slider to zero and get it very close with the gain during setup.

Also, if you start at zero you have a reasonable range to bring them up or down on the slider. There is more down than up partly so you can fade things clear out and also because it's a bigger problem is someone yells into a mic than if they back off a step or two.

Zero also lets you bring things up a bit, or down a bit, or fade something out and you always know where to go back to as a starter position, even if you weren't the one that did "setup".

Typically you also have finer control on a slider so you want to use them, not the gain knobs during service, other than, situations like Lee Ann described. Throw in sstanton's comment about pre and post and you've pretty well covered it.

Now, all that said, modern boards have a LOT of dynamic range, a LOT of overhead before clipping and SNR's that can be compromised by 20dB and still be better than people can detect out in the house. So being off a bit on the gain is NOT the end of the world.

[dmot]

Originally Posted by Mark Finley

But wouldn't gain at unity mean that all incoming signals have similar signal strength, and then you use the sliders for output volume?
for me gain=input, and sliders=output

I agree with unity of gain, but not unity of sliders.

I probably shouldn't be trying to answer this and leave it for someone who understands a lot better but "fools rush in." We use a Mackie 24 and set everything to unity - faders, master. Then we solo the channel and turn up the gain until we get unity on the power meter. At that point our amp is set to adjust the overall volume. Then we check the faders to see if we have enough headroom for any changes we may need to make. If not we fudge the gain to give us the room. Are faders are then used to mix the house. We try to mix monitors pre-fade so we don't change the mix for the musicians when we are adjusting the house. My understanding was that when you are not at unity you have the potential to get more noise in your mix and you can over/under power any processing you may be doing.

[cmchamp]

There are too many variables here for me to answer definitively. Using the trim (gain) to mix introduces the possibility of less headroom and more opportunity for clipping input stages making the overall end product less than desireable. Setting "Unity Gain" improperly can introduce much more noise than accepbable at the input stage. The best solution - believe it or not - is to read the recommendations for level setting for the mixer you're using. I've had 'old school' set the trim (gain) on a Mackie 24VLZPro the old way - level up to clip, back it off a bit. That doesn't work on a Mackie board. Additionally, if you don't set your input trim (gain) conservatively enough with vocals during sound check - you'll find after the 'energy' of the service gets going, those vocalse that were at 'unity' are now too close to clip for comfort.
C.

[Mark Finley]

I"m going to admit to doing something that is probably amaturish, but it workds well for our board, and it's easy to teach.

On our board (A&H GL2200) there are four lights for every channel. one green, two yellow, and a red. I tell the mixer guys to set the gain so you get a solid green and maybe a yellow, but if it's consistantly peaking up to 2 yellows you might want to back off a bit.

Flashing green = bring it up a bit if possible (sometimes you can't without feedback)
Solid green & occational yellow = Great
Solid yellow and occational 2nd yellow = back off a bit
Red= you're fired (just kidding)

If we wind up with a slider that is almost all the way down we might fudge those rules a little, but for the most part it works well.

[JCardwell]

Ideally if the gain structure of the board is set properly, so that when you set all the sliders at Unity you have a good basic mix, vocal and instruments, you''ll have enough head room with the sliders you can make minor adjustments to your mix to get the correct mix and your should rarely if ever have to touch the gain control for a channel. I was taught that if you have to constantly adjust the gain for the channels the board isn't set up properly for the venue.

[Gracetech]

To get a signal that is clean to pass through the board you have to get the gain of up to unity. If you pass a lower voltage signal through the board you are liable to pick up more noise as it travels through the console. Now granted we are talking about a very minute amount of noise but thats about the only difference. The noise can really get you when you have things inserted in your channel though.

I let my one engineer that mixes by gain do it his way because their is no real noiticable difference in a live setting. Now that said don't ever try to pull that stuff in the Studio because you would probably get fired. If you think it is fun to reset the board after you guy mixes just have him zero out the board when he's done . All my sound opps are trained to zero out the console when their through. I find this is good training for the sound opps and dosen't make for a boring sound when the next opp steps behind the board. Just my 2 cents. It's actually a good thing that we are mostly digital now so my opps can pull up thier settings from the previous week they mixed and get it sounding their way pretty quick.

crt

[JHVideoGuy]

This topic has been discussed in several other places on line (CSC and SynAudCon mailing lists to name a few). The best explanation of how to properly set the gain structure for you console is from Bill Johnson. It's the 1st article "The Target Gain Method".

Basically he talks about setting the maximum gain per channel as to not overload the busses in the board. He explains how to go about this. I don't know how this applies to VCA consoles as the busses are not signal paths. I guess you'd figure it out as to not overload your main. And I don't think you can overload a buss in a digital board since it's just numbers once it's passed the head amp. But I'm just speculating here.

-dave