Negative - any sound man worth his salt incorporates compression, gating and limiters into their rack as part of the signal chain. THEN when they "rehearse" their feedback they set the system up so that the attack speed is fast enough to catch it and level the signal before it even becomes a problem. I can take my vocal microphone (wireless Shure Beta 87) out to the middle of the dance floor in front of the PA and sing a song because we have everything running through a pair of PreSonus ACP-88 Compressor/Gates. Buy PreSonus ACP-88 8-Channel Compressor/Gate | Compressors & Limiters | Musician's Friend And to that end, there is a threshold on each and every mic on the stage - I can sing softly into the mic, I can sing loudly into the mic, and I can scream into the mic - everything is picked up and dynamics are heard up to a certain level. At that point the compressor/gate kicks in and levels the signal so that it never rises above a certain point. Gain levels are important, but for our PA the real key to the elimination of feedback are the compressors. Seriously - we never have a feedback problem - it just isn't part of the equation, no matter where the mic is.