Live Sound - what to do with the summing EQ

[HeadCrusher]

so i did my first live sound the other night.
it was a really small DIY location so nothing special could be expected. equipment over there was really cheap but i only had to mic the bass drum und voices of course anyway. so again: really small!
but...
from time to time i had a few feedback problems (which i had already expected because of the cheap mics and the singers actually standing in front of the pa) which i thought could have been less if i knew how to use the summing eq, right?
so here's my question: are there any certain frequencies you might wanna turn down in order to prevent feedback from vocals in a live situation?
something else: during breaks between songs the bassdrum mic used to slowly start feedback as well when the bassplayer hit a note. is that normal?
oh and btw: there were no compressors, gates, whatsover so i had enough to do re-gaining the vocals everytime the singer decided to sing respectively scream and so on... hence i couldn't try out a lot during the concert itself.
again: really small location!

 

[joeymusicguy]

with venue's like this, its pretty much your job to be the compressor and the gate

ride the volume levels during songs, cut out sound on mic's that aren't in use between songs, etc. etc.

stuff that computers do for us in recording situations via automation, or stuff that good engineers do on actual boards

 

[Ermz]

600 to 800 are common honky feedback frequencies in live situations, particularly for vocals. I mean the rest really depends on the location and positioning of speakers/mics. You're basically assured to get feedback around 6 to 8k

Kick mics are commonly gated in live situations to prevent the problem that you're describing. I have to say that I've never had feedback issues with kick mics though.

A good way to tune a system is to start by playing a CD through that you know really well. Use the graphics to roughly tune it to how you think it should sound on a flat system. Then run a vocal mic through and just keep speaking into it and turning up the volume until you get feedback squeaks. Identify what frequency the squeaks are and turn those frequencies down on the graphic. Repeat this process until you have enough volume out of the system, without having chopped up the sound quality horrendously.

 

[elmuchoescadawg]

The frequency of feedback is dependant on loads of factors, which mics, which speakers shape of room, height of ceiling etc etc. Best thing you can do is before sound check have a bit of a shout around (you know the old one two, one two song right?) and find the offending frequencies and bring them down on the Front of house (summing) graphic. You will also need to do the same with the monitors as well. A gate on the kick drum is pretty important basically because its the instrument your likely to butcher the most with EQ so you will need to protect again any real boosts.

Also with room and channel eq, cut frequncies rather than boosting them if you can. It will really help.

 

[HeadCrusher]

thanks for the tips so far.
the funny thing is: in this venue i couldn't have done anything more than i already did (apart from the summing eq) - no compressors, no gates and no monitors!
i might get to mix there again at the beginning of may - already interested what will be better worse.
btw: when i turned up the kick drum (the fader, not the gain) really high there was a constant "click click click" coming out of the speakers. and when i set the master fader to a certain level the right speaker wouldn't give any sound. just a bit more or less would make it play again. (did i tell you about the crackling sounds when moving the master fader?? )

 

[Ermz]

I've done great live mixes in venues that just had a desk and FOH and monitor EQs. You just have to learn how to tune the system well and you shouldn't run into too many feedback problems. Usually the problem will be getting enough level out of an underpowered system.

 

[elmuchoescadawg]

thanks for the tips so far.
the funny thing is: in this venue i couldn't have done anything more than i already did (apart from the summing eq) - no compressors, no gates and no monitors!
i might get to mix there again at the beginning of may - already interested what will be better worse.
btw: when i turned up the kick drum (the fader, not the gain) really high there was a constant "click click click" coming out of the speakers. and when i set the master fader to a certain level the right speaker wouldn't give any sound. just a bit more or less would make it play again. (did i tell you about the crackling sounds when moving the master fader?? )

That system sounds like what we would call broken