apfelaudio / eurorack-pmod

A eurorack-friendly audio frontend compatible with many FPGA boards, based on the AK4619VN audio CODEC.
https://apfelaudio.com/modules/available/pmod/
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cores/filter: improve low-pass filter example #25

Closed schnommus closed 1 year ago

schnommus commented 1 year ago

The example filter core works but it can be a bit unstable at low cutoffs and seems to suffer from some internal clipping. The current implementation is just lifted from the tinysynth project.

This PR replaces it with ladder low-pass filter that should be a bit more stable, allow self-resonance and sound a bit better. Maybe oversampling would be nice as well.