Acid Filter

chirping acid resonance filter with envelope tracking, accent and slide

Acid Filter is that typical squelsh filter you know from acid house records - just with some extra control functionality.

The original Roland TB-303 bassline synth is cool, but it's limited to very simple oscillator waveforms. I wanted to make its diode ladder squelsh filter unit work on whatever audio material I feed it with. An input detector triggers an internal filter envelope either via the main input or a sidechain channel and MIDI note events control accent and slide by velocity and note-overlap.

Hint: Since it's a filter plugin without an oscillator, you have to use a synth with portamento as an input source if you want to achieve those typical TB-303 pitch slide effects. The filter cutoff itself slides as well but it can only accentuate what's already audible.