#1
I'm house sitting for my grandparents for a couple days so I wanna use this time to fine tune my bands PA system (my grandpas our drummer). My question is.....the mixer, the EQ, the crossover......they all have input/gain knobs/faders......how am I supposed to sync them up? I know for the mixer its best to leave the main fader on unity/0 and then bring up the channel faders as needed, but what about the input on the EQ and the crossover? Should I leave those at unity/0 as well? It doesn't have as full of a sound if I do that but if I turn them up I obviously get a decent amount of hiss (we don't have a noise gate).

Also for the crossover what is the best settings to put it on when it comes to the other settings on it? We have been keeping the "cutoff" on 240hz for a while. Is there a "general/best setting that FOH guys use?" And should I adjust the low and high output knobs for personal preference? I'm gonna keep messing with it while I wait for some of your suggestions. Thanks
#2
I turn up the gain till the signal is just under the red at the loudest point, the use the faders to determine how loud within the mix of the P.A. The EQ is about tone so it's just personal presence.

Sorry if I didn't answer all the points clearly, i'm really tired.
#3
Quote by anthsband
My question is.....the mixer, the EQ, the crossover......they all have input/gain knobs/faders......how am I supposed to sync them up? I know for the mixer its best to leave the main fader on unity/0 and then bring up the channel faders as needed, but what about the input on the EQ and the crossover? Should I leave those at unity/0 as well? It doesn't have as full of a sound if I do that but if I turn them up I obviously get a decent amount of hiss (we don't have a noise gate).


The term for what you are asking about is "gain staging." You start at the end closest to the source and go from there. So, in a PA, the source is the microphone. Your first stop is the gain/input/trim knob on the channel. (different manufacturers label them differently, but these are the most common).

Start with the channel and the master fader at zero. Not unity gain, but zero. Usually labeled as minus infinity. There should be a meter somewhere - probably just a little LED light. Turn up the input/trim (with the mic on and picking up signal as if you were practicing) until it starts to flash red every now and again, and then back off it. Red means clipping. Clipping means distortion. Lots of clipping means blowing the inputs. The odd little flash of red is no big deal, but ideally, you don't want it to flash red at all. Some mixers will flash yellow before it goes red. That can be helpful.

Once you've got your inputs set, put your master fader at unity. Time now to set your channel faders. At this point, all you're doing is setting levels relative to each other. Don't worry about your overall volume just yet. Set your channel faders to where you think you want them. EQ each channel to taste. The EQ *should* be before the input trim, so adjusting EQ *shouldn't* start clipping your channel. Make finer adjustments on your channel faders so that your volumes are good relative to each other.

Finally, adjust your master fader so that the volume is where you want it. I'm assuming this is a powered PA mixer, and that the mixer is not going into a separate power amp. Otherwise, there's another step involved.

Quote by anthsband

Also for the crossover what is the best settings to put it on when it comes to the other settings on it? We have been keeping the "cutoff" on 240hz for a while. Is there a "general/best setting that FOH guys use?" And should I adjust the low and high output knobs for personal preference? I'm gonna keep messing with it while I wait for some of your suggestions. Thanks


Ah, crossovers....

Your settings for this will be dictated by what the crossovers are controlling. Check the frequency response of the speakers you are using. That should at least give you a starting point.

Let's say you've got:

a pair of 12" PA speakers rated at 80hz - 18Khz.
a pair of subs rated at 40hz to 120 hz.

Your speakers overlap between 80hz - 120hz. Your crossover setting should be somewhere in that range, then. Where will depend on where your speakers seem to best respond. For instance, if the upper range of your subs is pretty tinny at 110hz, but your mains are pretty solid down to 90 hz, then the best place for your crossover is probably around 90hz.

In any case, 240hz sounds high... unless you've got a crossover between a pair of lower-range bins rated upwards only to about 400hz, and a pair of tweeters (aka horns) rated from 200hz and up.... but that would be pretty weird.

More likely would be a pair of mid-range speakers rated from 100hz - 12 khz, and a pair of horns rated from 10 khz to 18 khz... in which case you would set your crossover for somewhere around 11 khz.

Once you've got that dialed in, the output knobs can be used to "season to taste."

CT
Could I get some more talent in the monitors, please?

I know it sounds crazy, but try to learn to inhale your voice. www.thebelcantotechnique.com

Chris is the king of relating music things to other objects in real life.
#4
thanks for the tip, although I must have worded my original question weirdly cuz both of you responded talking about adjusting the gain on the channels of the mixer haha I'll try and ask it more clear.
Heres what we use:

http://pro-audio.musiciansfriend.com/product/dbx-Stereo-2WayMono-3Way-Crossover?sku=H72800

http://pro-audio.musiciansfriend.com/product/Yamaha-MG166CX-16Channel-Mixer-With-Compression-and-Effects?sku=630257

http://pro-audio.musiciansfriend.com/product/dbx-215s-Dual-15Band-Graphic-EQ?sku=H71336


The input/gain knobs I was referring to were the ones on the crossover and the EQ units....both knobs are on the far left. Should I be keeping those at unity/0 as well as the main fader on the mixer so everything is kept at a "clean even volume?"

Also Axeman you mentioned something about the mixer being powered......it isn't we have an unpowered mixer that goes into 3 power amps (one for the monitors, mains, subs). I read somewhere that you are supposed to keep the power amps fully cranked and then adjust the volume using the mixer to fully take advantage of the power of the power amps.

EDIT: You said about looking at where the subs/mains frequencies match up.....we use Harbinger speakers...the subs are 32-250hz and the mains are 40-19khz. Last night I found that setting the crossover at 140hz sounded the best. 240 was muddy and anything below 140 just sounded really weird
Last edited by anthsband at May 27, 2011,