Media Players
answer:
In general the mix in the front-of-house should not affect the feedback situation if the mics are behind the PA speakers. Ringing out the feedback in the monitors can be done with the mains muted. For monitors, give the performers only minimum of aux signals they ask for to keep stage volumes and feedback at bay. Good, flat response monitors and and mics are key to feedback reduction. Also, proper aiming of mics and monitors assists in feedback reduction.
Amplifiers, Cables, Cases, CDMP3 Players,
This is a problem and it's one that sould be solved. When the stage volume gets out of control, the house sound suffers both acoustically and because the musicians get distracted and aren't playing as well as they could. Headphones aren't the solution, unless everyone is wearing them (which puts the stage volume well under control).
Berwyn, Bishop Hill, Brookfield, Sound Catalog,