[sdiy] Hardware/software LFO Designs

[Scott Nordlund]

Variable sample rates quickly become a dead end once you try to do anything cool
or have more than one oscillator.  There are advantages, you don't have to worry
about interpolation or aliasing, but much more significant disadvantages for
anything beyond monophonic stuff.

I suspect the original Emax, original Emulator III and Korg DSS-1 may have been
the last variable rate machines (if they actually were, I don't know).


> From: grant at musictechnologiesgroup.com
> To: Synth-diy at dropmix.xs4all.nl
> Date: Sun, 4 Jul 2010 21:07:59 -0700
> Subject: Re: [sdiy] Hardware/software LFO Designs
> 
>> Your suggested design is slightly different to mine, in that you're 
>> talking about a
>> variable sample rate, whereas I had a fixed sample rate of 19.5KHz. I'd be
>> interested to know what difference this makes, if any.
> 
> Oooh. That's interesting. I know regarding VCOs there are various approaches 
> using fixed sample rates vs. variable sample rates. Are there any 
> discussions online detailing what must by now be a well worn path?
> 
> I'm am certainly not going to get that kind of speed. My DAC is I2C and my 
> CPU doesn't have hardware I2C, so the best I can get out of it is an update 
> every 170us (if I don't do anything else) and that's only a 5.9kHz rate. And 
> no extra pins. I'm definitely going to have to scale back my expectations.
> 
> GB 
 		 	   		  
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