[sdiy] digital synth design.

[Alwyn Lloyd]

Aloha,

> >I think software isn't that much of a problem (unless you are a pure
> >hardware man) - as long as the patch structure doesn't involve much
> >synthesizing and processing, i.e. mostly sample playback.
>
> Ah, but here the fun starts already:
>

*snip list of paramaters *

exactly.  the paramaters and how you deal with them, and which ones you
offer to be used define how creative you can get with something like this.
and the problem with doing this in software is that goddamn feature creep.
:)

obviously, in a limited resource processor, you start having to skimp on
stuff.

To do fun stuff however, you are going to need modulation sources, such as
lfo's envelopes etc, and destinations, like amplitude, filters etc. mabey
even something more exotic, like loop points etc...

velocity scaling would be nice,  however, if you made perhaps something
similar to the emu proteous engine, you could have several "layers" and
fade a differnt set in on a differnt velocity and fade the other out.  The
options are wide open really.


> >Functionally, hardware shouldn't be too hard as well. Main problem
> >would be to find a suitable processor chip that is a) available in
> >single quantities and b) isn't too nasty to solder (I'm thinking hard
> >core SMT here).

yeah. BGA is out :P  unfortunatly, most processors with the nice features
these days are at least tqfp or lqfp.  Its not _impossible_ to solder
these, surely ??

at least i have the option of going the the uni's electronic fab shop and
getting them to make me a board for a carton...

> Next question is if you want to burden all playback onto the processor,
> or if the processor only becomes master control where playback is done
> by either a (bunch of) slave processor(s) or some dedicated hardware
> circuitry (counters clocked with variable frequency or phase
> accumulators).

i personaly would like to try and do it all on the processor, if only to
keep the hardware design cleaner.  Most processors also have a fair bit of
grunt under the hood there, im actually suspecting the limiting factors at
this time with my current concept are going to be caused by memory space
rather than processing limitations.  However, i could be in for a rude
shock.


Alwyn (Feature Creeping already )  Lloyd