The Coleman Audio CA500EQ is a 4 band stereo equalizer. The inputs & outputs are balanced on XLR connectors. There is an input level control so you can adjust the audio signal before equalizing to help prevent clipping, and an output level control to readjust the gain of the signal with equalization. The EQ in switch turns the entire equalizer on or off. The stereo/mono switch allows the CA500 to become a mono EQ unit. The audio passes through the left channel first and then througho the right channel providing more EQ options. The high frequencies (8kHz, 10kHz, 12kHz and 16kHz) can be switched between shelving or peak EQ with 10db of boost or cut in 2db discrete steps. The low frequencies (30Hz, 60Hz, 100Hz, and 150Hz) are shelving EQ with 10db of boost or cut in 2db discrete steps. The two mid bands are peak equalizers with frequencies overlapping by 1/4 octave and have up to 14db of boost or cut in 2db discrete steps. The circuits are designed to musical scales, not to mathematical relationships and the variable "Q" circuits maintain the tonal balance as the amplitude is adjusted.