The LxD in a narrow 4HP module in which two different Low Pass Gates carry out their daily task. They were designed to operate independently or combined to form the back end of a synth voice.
Channel 1 is a mildly resonant low pass filter with a slope of 12dB/octave. Channel 2 is a non-resonant low pass with 6dB per octave.
Both renounce cutoff frequency controls and limit themselves to a non-attenuated CV input. The Strike input makes a percussive cutoff modulation even lacking an envelope; just inject a trigger signal and the rest is handled by the inbuilt vactrol which is responsible for the organic-percussive characteristic of the modulation.
The output of Channel 1 is normalled to the input of Channel 2, putting the two channels in series to form the VCF-to-VCA arrangement made popular by many classic monosynths of the 1970’s.
The sound of the LxD is quite unique from the VCF/VCA in those classic synths though, as it is fine tuned to compliment the more harmonically complex sound sources common in the modular synthesizers of today.