[sdiy] New dsPIC chips with on-chip audio DACs

Tom Wiltshire tom at electricdruid.net
Fri Mar 28 13:10:05 CET 2008

On 28 Mar 2008, at 09:13, jbv wrote:
> as I love to play the devil's advocate once in while, I'd like to  
> ask if
> building synth voices is really the only horizon that offer those new
> & cheap & fast dsPIC chips ?
> I really don't want to trigger any flame war, but I just wonder if  
> it's
> sufficient (if not a bit frustrating) to approach these chips only  
> from
> an analog synthesis point of view (MIDI -> DCO -> VCF -> VCA)...

No, true. The old analogue paradigm is obviously only one thing you  
could do with them. However, I do think it's still got some life in  
it yet. The basic VCO->VCF->VCA signal path corresponds with three  
elements of human sound perception; pitch, timbre, and volume. As  
such it is a comprehensible technology, as each of these elements can  
be altered independently. That's the idea anyway.
I don't think that classic analogue synths provide anything like  
enough variation in each of these parameters though. Three or four  
waveforms isn't anything like enough sonic variation, and a simple  
lowpass filter only offers more harmonics or less harmonics. Not  
everso exciting. (How's that for starting a flame war?!)
That said, I do one day want to build an analogue polyphonic  
instrument like the Jupiter 8 or Prophet T8, and I saw a way to do it  
with a chip like this.

If someone would like to try, I'm sure you could write a 6 or 8  
operator FM synth voice with one too.

> I'm no dsp wizard, but well, a little bit of imagination never  
> kills...
> so why not ask how many osc can be run in parallel for additive
> synthesis, if FFT/iFFT or NN or GA can be implemented, and how
> it could paved the way for new kinds of music gear (affordable and
> made by DIYers), and why not for new kinds of music ?

Ok, I'm convinced! After the analogue voice and the FM voice are  
sorted, we'll be able to go well beyond what's been done before.  
Myself, I feel like I'm still learning the stuff I need to know by  
recreating things that have already been done. People like Dave Smith  
(to name one synth pioneer who is still around and producing new  
instruments) has a 30 year head start on me. I can't run till I can  
walk. But I do hope to get there eventually.


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