This is a collection of optimized biquad filters. They are divided in two groups: static and dynamic filters. Static filters calculate their filter coefficients in “green”, so you can set the cutoff and resonance parameters with GUI controls or hardwire them. Dynamic filters receive their cutoff frequency input as a stream so you can drive it with a modulation source. Static filters demand slightly less CPU than their dynamic counterparts.
For each filter there are two implementations: the so-called Direct Form II and the Transposed Direct Form II. They should be interchangeable for most applications.
The filters will work fine in the audio range with moderate modulation. They will not work with cutoff frequencies below 20 Hz nor for very fast modulation.
Version 1.0: Static and dynamic variants of LP, BP, HP and AP, respectively.