Re: What's this all about?
Peace, love and magic!
Either that or "wanted" is the loudest source and "unwanted" are the sources under the gate's threshold.
This "Primary Source Enhancer" is a very pretty name applied to a feedback suppressor. A long time ago (more than a week) when I was trying to understand feedback, I wrote the following. Hope it's helpful. As always, comments, corrections and catcalls are solicited.
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Feedback Avoidance:
A margin of gain before feedback of at least 6dB is required for reasonably good sound. Smaller margins that still avoid feedback sound bad. When you can increase volume to the point where the whole band is uncomfortably loud and you still don’t have feedback, you’re in pretty good shape.
Feedback occurs when the volume from the loudspeaker going into the microphone is greater than or equal to the volume of the desired source going into the microphone. There’s a bit more to it than this (phase), but that is what you need to keep in mind. Thus, you have two main things you can work with to increase the amount of gain you can get from the loudspeakers before feedback occurs; get the loudspeakers further away from the mics or get the mics closer to the desired sources.
Every doubling of distance decreases SPL by 6dB. Halving of distance increases SPL by 6dB. Loudspeaker sound into mics is bad, thus increasing the distance between the two is good. Violin sound into mics is good, thus decrease this distance when possible. It is usually much easier to decrease the mic to source distance than to increase the mic to loudspeaker distance. Changing a violin mic from stand mounted type 2’ away to miniature bridged mounted type 1.5” away will increase your margin of gain before feedback by 24dB. Microphone to source distance is the secret to feedback free sound reinforcement.
Maintain individual control over left and right house loudspeakers so you can mix stage left instruments to stage right loudspeaker and vice-versa as a feedback reduction tool when needed. Get a console that allows polarity reversal on each microphone input channel. The use of this switch on a channel near feedback can help. Use directional microphones pointed away from the loudspeakers and toward the sources. Use directional loudspeakers pointed away from the mics and reflective surfaces in the room and toward the listeners. Teach vocalists to eat their mics. Try not to use more than one microphone per instrument – every open microphone increases the potential for feedback. When possible, avoid mics and use pickups.