From: <
jhaible@...>
>
> A typical BPF (like the Emu UAF, Oberheim SEM filter in BPF mode, and many
> many similar filters) are two pole designs. For a good vocoder filter (a
single
> vocoder BPF!) you'd connect 3 such filters in series, two of them with the
> same Q factor, the 3rd with a different Q, and center frequencies spread
such
> that the "middle" filter is halfway between the "outer" filters on a log
frequency
> scale. Two such blocks are needed for analysis and synthesis of one
channel,
> and 20 channels were a good choice for the "classic" Sennheiser vocoder.
Out of curiosity, what sort of response is this and why is it good for
vocoders? (I would guess that for vocoder channels you'd want plenty of
discrimination between channels.)
...Craig