Built-in 24dB per octave crossover. Rotary low mix control to adjust the amount of signal used for low frequency sound enhancement. Rotary tune control to adjust the center frequencies of the high pass filter from 1 to 8kHz. Rotary processor control to adjust the amount of processing in overall sound mix. Rotary high/low mix control to adjust the amount of high/low frequency signal used for sound enhancement. IN/OUT switch operates on both channels, in the OUT position the unit is bypassed. Balanced XLR inputs and outputs.