Getting the most out of your rehearsal time and effort:
Show up on time. Showing up is 80% of the gig. On time arrival eliminates issues.
Know the songs. Learn songs at home. Rehearsal is for maximizing everyone's performance and is NOT the time or place to be learning the songs.
EQ for high volumes: The human ear hears more high end rat-blatt and low end boom-rumble as volume increases. The old classic "smile" EQ will not work at high volumes. You have to use midrange, and back off on highs and lows to get a nice fat tone at performance volumes.
A word on volume: Fill the room, don't kill it: it is possible to just plain over-power a room. That's fine if you want to sound like a Saturn 5 lifting off; but too much if you want to sound like music.
Most "sound" problems are EQ problems. Start with all sliders flat, then SLOWLY alter the settings. 3 dB is a lot of difference. Maxing out any slider on the EQ is adds up to 12 dB... which is too much.
Today's "modeling" amps/processors and such produce processed sound. The sound tends to lack dynamics and "cut", so guitar players compensate by kranking it up. Like it or not, guys, less is more when it comes to effects and cutting through the mix. Excessive compression gives a very narrow window to cut through. Fat sound, just loud enough, comes through better. How do your favorite pros solo? Big, fat and sweet would be my guess.
The same applies to keyboards.
Time based effects, like echo, phase, delay and so forth, that may sound great at low volumes produce sonic mud at higher volumes. This is because multiple images of the sound are bouncing around (along with all their harmonics and dynamics). More volume just adds more mud. Turn the effect mix down at higher volumes for improved clarity. Get loud and hear yourself too, imagine that.
EMG guys... do put in new 9 volt batteries when the pups sound ratty.
Guitar guys.. try your guitar volume dials at about 6.5 - 8. There is a narrow sweet spot in there somewhere that gives you the power and harmonics you crave, but not the high end racket you don't. Twiddle your tone knobs for fine tuning the sweet spot.
On the PA, if you are getting a low end feedback. Try backing off on the bass EQ.
Keep all mics pointed AWAY from any PA speaker or monitor. If the mic and speaker get talking to each other directly, the result is a feedback loop.
Use a bass amp for bass. Guitar speakers don't have the travel or the thump for the job so they sound crappy, and it beats on them.
Don't mic drums in a small room. It does not help, and the singer will have a harder time hearing himself.
If the drummer can't hear his own set, the band is playing too loud.
