There have been some posts lately about filters with parameters that can be controlled by audio signals, so I'm posting some filter abstractions I made.

[biquadm.mmb~] -- just like [biquad~] (i.e. accepts coefficients as a list) except you can give it an interpolation time to smooth transitions.
[biquad.mmb~] -- a biquad filter with signal-controlled parameters
[filtercoeff.mmb] -- creates a list of biquad coefficients with various filter choices.
[filtercoeff.mmb~] -- like [filtercoeff.mmb], but with signal-controlled parameters and outlets for [biquad.mmb~]

The help file covers all of the objects. Not the best help file I've made, but it should explain it enough.