[sdiy] My FPGA synth implementation

[Chris Strellis]

Hi Ian,

> Very nice project!

Thanks :D

  Would there be any way to modify the eight 
> frequencies?  Things like omitting some of the lower ones and 
> adding more 
> high ones, or making more general anharmonic sounds.

Yes, it would be possible to change the frequencies of each oscillator relative to one another.  Perhaps another 8 controls can be added to do this.  As you can see it can soon become unwieldy to control the synth.

My two controllers have 16 sliders each but only two user programable slots.  This gives me 64 sliders worth of control.  I do have two Peavey PC1600 16 fader controllers as well with 50 programs slots each so I could have lots of control but you see it's getting complex :S

Although I set the synth up to give standard short sounds for sequencing purposes it is much better in generating long evolving sounds.  I should do one of these as an mp3 example with accompanying spectrogram :)

However, with only 8 oscillators it still isn't very harmonically interesting.  It is very much draw bar organ territory.

The main thing is that I now have a development platform to try new algorithms and ideas.  Does the World really need another additive synth or virtual analogue?

I thought maybe have a 16 tap FIR with each coefficient represented by one of the sliders.  With the input driven by multiple saw or square oscillators, it would be interesting to hear the effect of changing the coefficients on the fly :D

I might do an Excel spreadsheet to see if anything interesting pops out.

Cheers

Chris