[sdiy] Vocoder dabblings

[KD KD]

Really nice!
Impressive coding, getting all those SVF's etc and the whole lot sounding
so well already, way better than many pristine analogues, in fact better then
many VST's to.

Make a Euro module people will buy, the Rolls Royce's is waiting for you!

Ad a simple internal carrier and modulator oscillator, simple saw and
PW will do.

2012/10/21, Richie Burnett <rburnett at richieburnett.co.uk>:
> Hi guys and girls,
>
> Been playing about with coding up a Vocoder just for fun after recently
> having to design a filter bank for a commercial job.  Have included a few
> audio examples of the results I'm getting for those interested:
>
> http://www.richieburnett.co.uk/temp/vocoder1.mp3
> http://www.richieburnett.co.uk/temp/vocoder2.mp3
> http://www.richieburnett.co.uk/temp/vocoder3.mp3
> http://www.richieburnett.co.uk/temp/vocoder4.mp3
> http://www.richieburnett.co.uk/temp/vocoder5.mp3
> http://www.richieburnett.co.uk/temp/vocoder6.mp3
> http://www.richieburnett.co.uk/temp/vocoder7.mp3
> http://www.richieburnett.co.uk/temp/vocoder8.mp3
>
> Technical specs as follows:
>
> Processor is dsPIC30F6012A 16-bit DSC from Microchip running at 25MHz.
> Audio sample rate is 24kHz.  Vocoder is 20 bands (20 analysis + 20
> synthesis), each 1/3rd octave, filters are 8th order Butterworth band-pass
> response (24dB/oct slope each side)  (160 seperate state-variable filters in
>
> total!)  Lowest band is 60Hz, highest band is 6kHz, although the bands in
> the lowest octave do little with speech signals.  Sibilance from modulator
> above 6kHz is high-pass filtered and mixed in with the modulated carrier to
>
> increase intelligibility.  +3dB/oct spectral tilt is added for classic
> sawtooth/square based carriers, and -3dB/oct spectral tilt is added for
> white noise carrier.  No user-interface or spectral display.
>
> Modulator audio was either Radio-4 news, or audio sample played from Akai
> sampler.  Carriers are various waveforms or white noise from Roland SH-09,
> or hoover sound from Juno-2.
>
> Never built a vocoder before, either analog or digital so please be kind...
>
> -Richie,
>
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