Low cut SwitchActivates 40 Hz Butterworth, 12 dB/octave high-pass filter, one switch per channel.
Phase Invert SwitchInverts the phase at the output, one switch per output.
x1 / x10 SwitchMultiplies the low-high(mono: low/mid and high/mid) crossover frequency range of the front-panel markings by a factor of 1 or 10, one switch per channel.
Mode SwitchSelects stereo/mono and 2/3-way operation
LF Sum SwitchSelects normal (stereo) or mono-summed low frequency operation and disables Ch 2’s low output phase invert LED to indicate that this output is not operational in the LF sum mode.