> If you can tune the band, it's no longer a fixed filter bank. It becomes
> parametric, or at least, "paragraphic."
Yes.
>What you are describing here is
>really a classic parametric equalizer---"Cut/Boost," "Freq," and
"Bandwidth"
>are the three controls on each channel of a parametric.
And if a fixed filter bank is somewhat related to a graphic EQ (difference
being the way of attenuation), then the "filter bank" counterpart of a
parametric EQ would be - you guessed it -
the ordinary BPF. The existing MOTM triple resonant filter would be
a "semi parametric filter bank" (with external mixer), and a set of
SEM-Style
filters would be a fully parametric version. I don't want to tell more than
Paul
recently did on analogue heaven, but the SEM-style VCF to come will have
a few features that will go a little beyond your dreams of VC parameters
actually ...
> I've always wondered if a parametric ∗vocoder∗ would be interesting.
I never thought that. It's part of a Vocoder designer's hard work (;->) to
lay out the filters such that they are
- flat in passband
- steep at edges
- not overlapping
- but summing to 0dB with adjacent bands wide open.
You can never do this on the fly, with knobs for all the parameters.
It's definitely not as easy as just changing bandwidth.
I do encourage experiments like that, with individual filters and stuff
(who cares if things don't overlap as long as it sounds good ?), but
it would be sucide to design a self contained vocoder like that.
And in the end, a vocoder is a building block of its own, even if
it's full of components that would make nice stand alone modules
as well.
Just my opinion, of course.
JH.