The Three Sisters module has three individual filter paths: LOW, CENTRE and HIGH each with it's own input and output. ALL interacts with all three filters at the same time: the input feeds every individual filter input while the output mixes the filter outputs equally.
FREQ simultaneously controls the cutoff frequency of all filters but the behaviour differs depending on the mode (see below). The operational range is extremely wide. The V/8 input can be used for playing the filter tonally as LOW follows exactly adn HIGH & LOW approvimately 1V/octave.
SPAN determines the spacing between LOW and HIGH from CENTRE frequency but it does not affect CENTRE.
!Q controls the filter quality in a bi-polar fashion: beyond 12h position the potentiometer works like a normal filter resonance up to oscillation. Below center position is acts like an anti-resonance cancelling phases at low !Q settings and generally has a subtle character.
There are two modes of operation: crossover und formant:
LOW is a low pass, HIGH a high pass, both with a slope of -24dB per octave. CENTRE fills the gap between the other filters and is a band pass with -12dB.
Modulating FREQ will move the cutoff frequencies of LOW and HIGH but will alter the width of the pass band.
!Q generates two resonance peaks, these of LOW and HIGH.
All three filters become 12dB/octave steep band passes which is great for creating vocal results and percussive sound or to mix disparate sounds in an interesting spectral way.
In this mode FREQ will also move CENTRE's cutoff frequency. !Q generates three filter peaks and the anti-resonance inverts HIGH to a lowpass and LOW to a high pass.
It is recommended to play a lot and to experiment with the individual inputs and outputs for creating feedbacks or e.g. to modulate the SPAN parameter.
Use the filter as a resonator. for creating vocals, as a spectral gate, triple sine wave generator, frequency crossover or a spectral mixer.
audio inputs: high, low, centre, all
audio outputs; high, low, centre, all
CV inputs: Quality, Span
Freq input, FM input
3U Eurorack module, 10HP wide, 30mm deep
power consumption: 100mA @ +12V and 93mA @ -12V