The output of filter 1 is internally connected to the input of filter 2. A secondary input can still be fed into input of the second filter so that two signals are mixed but undergo different stages of high pass filtering. Depending on the frequencies/responses chosen for each filter this mode can produce sounds from the subtle to extreme high pass filtering where the fundamental and first harmonic are easily removed and higher harmonics boosted.
By feeding different control voltages to each filter and adjusting the filter and response pots on each filter sound, interesting dynamics as well as harmonic content can be created.
In this position both filters are uncoupled and independent.
In this position, the audio input into filter 1 is also fed (internally) into input 2 of the second filter. This allows for example, a left/right split of the original unfiltered signal with different CV modulation of cut off frequencies applied and different response (resonant peak) amounts chosen via the pots. Experimenting with different CVs controlling each filter frequency can produce interesting stereo filtering possibilities.
Each filter has an audio input level pot to further control the filtered outputs. We are also working on some audio/video demos of the DHPF which will be posted here in due course.