What are the equations for all those funny knobs?

[Brian Towles]

As I try to design my first VCF, I'm trying to correlate how
different filter quality names relate to the frequecny response
of a filter.  Obviously cutoff is cutoff.  What about resonance?
Does that have something to do with the Q value?  Also,
people are always talking about 12db/24db rolloff -- has
anyone ever designed a 36db rolloff filter?  Or is that just
too crazy !? ;)

Thanks
Brian