[sdiy] Oscillator sampler with sorting capabilities concept

[Jim Credland]

I don't know if it would sound good, but I'm very interested.   I'm also wondering what happens if you do one iteration of a sort between each cycle of a waveform.  You could start with just noise … it might sound like a boring waveform cross-fade, but it might not :)

How far did you get with the pure data implementation? 

cheers! J. 



On 18 May 2013, at 09:30, "cheater00 ." <cheater00 at gmail.com> wrote:

> Hi guys,
> I was wondering what you guys thought of this synthesis technique. Has
> anyone tried this? Could it sound good?
> 
> Here's a chat log between me and a fellow synthesis fan.
> 
> have you ever tried running a waveform through a sorting algorithm?
> That is, take each cycle and sort that. If you sort the waveform fully
> you should get something like a saw. But you could limit the amount of
> work the sorting algo can perform before the waveform cycle is
> released. If you put this parameter on a knob then you could perhaps
> have a somewhat-smooth transition from your current waveform to a saw
> waveform.
> 
> I think it could even work for analogue synths, you'd just need
> somewhat of a buffer
> 
> 
> you could have a sampler which works like this: it has a sync input
> and a wave input from a VCO. when the vco outputs sync, it starts
> sampling the waveform until the next sync. Once that's done, this is
> called "a wave". Now for the output. Every time a wave is sampled, it
> is placed on a queue (fifo). When a vco sync happens, the output
> module takes the next wave from the fifo and starts outputting it. As
> long as the wave is being output, syncs can be ignored (or instead, it
> could jump to the next waveform at index 0, or to the next waveform at
> the same index as it currently is). If there is only one wave left in
> the queue, and the device is getting sync pulses over and over, then
> it could either start outputting silence, or start outputting the last
> wave it had in the queue.
> 
> 
> this way it could work even delay-less (but would mangle the output in
> a fun way)
> 
> 
> Snd of course, while this happens the currently output waveform could
> be mangled by: sorting, randomizing, sorting or shaping according to
> the current waveform shape in a second sampler, etc.
> 
> 
> could be fun when run on FM oscillators which change pitch.
> 
> 
> So what "slaving to another sampler" would mean is that, in the master
> sampler you have the sorting algorithm, and it moves sample 4 to
> position 1. Then the slave sampler doesn't sort its own samples,
> instead it just moves sample 4 to position 1, just like the master
> sampler. I think this might only work if the wave are "normalized" to
> some length, or alternatively if the waves in the slave get resampled
> to the length of the master, or alternatively if the waves in the
> master get resampled to the length of the slave. Resampling slave to
> length of master would mean we either get a nice low-pass effect (if
> the resampling is band-limited) or we get frequency-dependent aliasing
> (if the resampling is not band-limited). The aliasing would not change
> position in an inharmonic way like it usually happens when you alias
> against a static sample rate (like when recording to a low sample rate
> interface); instead aliasing would add a timbral quality which would
> be constant across the keyboard, and work in a musical fashion.
> Because both the master and slave waveforms are sampled at the same
> clock rate, this aliasing process is immune to the clock rate of the
> samplers.
> 
> You could laso have the master send the current wave to the slave and
> you could have the slave use it to wave-shape its wave with that. So
> if the master has a rising saw, nothing happens, and if master has a
> sine wave, then you get a sine shaper.
> 
> If the master sends a wave, where the voltage level of the nth sample
> is instead replaced by the index it has after being sorted, then
> "slave sorting" could work simply by wave-shaping the slave wave by
> that master "sorting index" wave.
> 
> 
> Of course you could have the slave have its own sampling input and
> sampling sync input, but then have its *output* sync to the master's
> sync input or a dedicated output-module sync input. Then if the sample
> memory is really long, and the sync happens every now and then, you
> could have a stutter effect.
> 
> 
> You could even have "markers" in the wave, which happen when a third
> input is triggered. Then, once the output module get sync, rather than
> jump to the beginning of the current wave it could jump back to the
> latest marker or skip forward.
> 
> 
> And if you have a long sample memory then you can just trigger the
> input sync once and have a loop play forever.
> 
> 
> I wonder what everyone thinks of this?
> 
> 
> This is fairly similar to some of the stuff I did in Pure Data at some
> point, but I've only now figured out how this could fit into the
> context of a modular synth.
> 
> 
> Cheers,
> D.
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