The LFE module is a Low Frequency Effect module that controls the LFE channel for a sub-woofer in either stereo or surround. It is a management module that controls the level of the low frequencies from 3 sources.
The Knob at the top, OUTPUT LEVEL, is the master output level and is intended to be run full cloclwise. The next function is a button that reverses the phase of the LFE output. The LFE filter is already flipped out of phase, as the L-R filter is normally inverted. Make sure that if you use this as the LFE filter your sub woofer's internal filter is off or bypassed.
The Filter is a Linkwitz-Reilly 2 pole filter (12 dB/oct) with frequencies at either 80 or 120 Hz, as selected by the next button down.
One special function of the LFE is that it can sum all of the surround channels (up to 8 channels) through a rear D-sub connector that is selectable from the front panel labeled "5 (7) to LFE" Pressing this button switches off all inputs and allows the rear input to be active.
When this function is not being used the input to the LFE is from the rear V-Rack input "BALANCED INPUT". By pressing EXT IN, it switches the input to the "BALANCED INSERT RETURN" input on the rear of the V-Rack.
Each of the 3 inputs has a level control that allows a center calibrate position and then full adjustment above and below that.
The LFE also has a SOLO button that will put the LFE signal into the mains in the solo mode.
The BYP FILTER button, when out, shows that level by pulsating a green LED in the button cap, just like the MX and FX series. When pressed in, the button turns red and the filter is bypassed, but you are still passing through the circuit.