To compensate for Acoustical problems in the room.
To tailor the tonal quality of the performance.
Always start with no equalization (all controls set
Equipment manufacturers design their equipment to be used
with NO EQUALIZATION.
Only use equalization to eliminate problems (i.e. feedback,
too much bass, too sharp, etc.).
After the problems are eliminated, there is seldom a need to
change equalization to enhance the sound.
Room factors which may require equalization:
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).
Sound absorption by soft surfaces (seats, people, acoustic
treatment) causes loss at high frequencies.
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.
Adjust for differences in different types of Mikes.
Adjust for specific instruments (keyboard, guitar, sax).
Adjust to optimize sound for particular voices (men,
Eliminate feedback points unique to one Mike.
Reduce breath noise and "pops".
Compensate for "proximity effect" when performer "eats the
Adjust to increase gain before feedback.
Eliminate "hollow" or "ringing" sound.
Main System equalizer
Adjust tonal quality of main speaker system to compensate
for room acoustics (texture of walls, floors, or ceiling).
Only if necessary, adjust to increase gain before
Automatic Feedback Eliminator
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.