vocoders

[Martin Czech]

:::You can pick up Boss SE-50 effects boxes for $50 nowadays and they have a
:::built in 22 band vocoder. An analog implementation would require several
:::hundred dollars in parts, and the results would be indistinguishable from
:::the $50 DSP unit.


True, as long as you don't attempt to use the filter banks as such,
two seperate filter banks. With lots of feedback (each filter and whole
bank) and clipping in one of the earlier stages.

E.g. the trombone like sounds in my Eimert samples.
I haven't seen a digital system that can do this.

In order to cut cost of an analog implemetation I'd suggest
to design a pcb that serves for all channel slices, be it analyser or
synthesizer. 

Certainly a DSP driven version means least effort, as long as 
the DSP starter/programmer kit is not too expensive.
Short time FFT gives a good analysing efficiency.

btw.: does anybody know if wavelet transform is used in vocoders?
Basically this would mean to have severall hopping FFTs in parallel,
with different window lengths.

m.c.