Equalizer

· Why is equalization needed?
o To increase gain before feedback.
o To compensate for Acoustical problems in the room.
o To tailor the tonal quality of the performance.

· Always start with no equalization (all controls set "flat").
o Equipment manufacturers design their equipment to be used with NO EQUALIZATION.
o Only use equalization to eliminate problems (i.e. feedback, too much bass, too sharp, etc.).
o After the problems are eliminated, there is seldom a need to change equalization to enhance the sound.

· Room factors which may require equalization:
o Sound reflections off of hard surfaces (walls, ceilings, and floors) causes uneven frequency response because of out-of-phase reflections (i.e. drop a stone in a pond and watch the ripples as they hit the shore and reflect back).
o Sound absorption by soft surfaces (seats, people, acoustic treatment) causes loss at high frequencies.
o Every room is different! Some seem to increase high frequencies, others absorb highs. Some resonate with base, others seem to have no bottom end at all.

· Individual channel equalization on the Mixer.
o Adjust for differences in different types of Mikes.
o Adjust for specific instruments (keyboard, guitar, sax).
o Adjust to optimize sound for particular voices (men, women).
o Eliminate feedback points unique to one Mike.
o Reduce breath noise and "pops".
o Compensate for "proximity effect" when performer "eats the mike".

· Monitor equalizer
o Adjust to increase gain before feedback.
o Eliminate "hollow" or "ringing" sound.

· Main System equalizer
o Adjust tonal quality of main speaker system to compensate for room acoustics (texture of walls, floors, or ceiling).
o Only if necessary, adjust to increase gain before feedback.

· Automatic Feedback Eliminator
o This is a special type of equalizer which "listens" for feedback, determines its frequency, and automatically sets a narrow notch filter to eliminate it. Multiple notch filters are set at different feedback frequencies.