The MCFx2 is ALM's state variable 'MCF' filter made double. It features 2 identical classic analog 3 pole state variable filter cores each with Low, High and Band Pass (or Notch) outputs. Direct and voltage control is provided for both filter cut offs and resonance. Switches allow the filters to function as one, with the 'Feed' switch internally routing audio from one filter to the other in series and the 'Link' switch linking the cut off controls for both filter cores. MCFx2 expands on the great sounding MCF filter to offer both serial and parallel functionality for stereo operation, dual peak, tighter slopes and other complex filtering set ups.

FREQUENCY CONTROLS
Sets the base frequency for the filter cut offs. The v / oct and frequency inputs are added to these.

RESONANCE CONTROL
Sets the level of resonant peaks atop the cut off frequencies. The resonance can get particularly aggressive going into self oscillation with the control past 12 o'clock.

OUTPUTS
Each filter output is 3 pole with an 18dB / oct slope.
Low - low pass filter outputs. Passes frequencies below the cut off.
High - high pass filter outputs. Passes frequencies above the cut off.
BP / Notch - band pass or notch filter outputs. Jumpers on the rear of the module select one or the other for each filter.
Passes frequencies within (BP) or outside (Notch) a narrow region around cut off frequency.

LINK BUTTON
Links the left cut off to parallel control both filters. The right controls will now set the max range of the right core. Both filters will track together when the right cut off is fully clockwise.

FEED BUTTON
Routes the output of the left filter core to the input of the right (unless patched), with the desired output filter type selected via jumper at the rear of the module.

FREQ INPUTS AND ATTENUATORS
Control voltage inputs here are combined with knob offsets to set the final cut off. Attenuversion control allows for both attenuation and inversion of the CV. Expects approx. -5V - 5V input.

RES INPUTS AND ATTENUATORS
Attenuated control voltage inputs here are combined with knob offsets to set the final resonance.
Expects approx. -5V - 5V input.

AUDIO INPUT 'In'
Signal inputs to the filter cores for processing.
Input sources may need to be attenuated, filter will drive from hotter input levels.
The Left input is normalised to the right (unless 'Feed' is enabled).