[sdiy] Analysis of frequency variation in analogue synths

[Ingo Debus]

Am 04.05.2007 um 02:52 schrieb Magnus Danielson:

> The one-cycle waveform repeat vs. continous waveform experiment is  
> interesting
> in that it attempts to remove time-variant modulations except those  
> at and
> integer multiples of the waveform fundamental itself. Weither it is  
> PM, AM,
> FM, drift or any obscure combo or something else doesn't really  
> care. There is
> however a problem with the approach and that is that care needs to  
> be taken to
> ensure that the VCO is tuned to form an integer (or near integer)  
> multiple of
> samples. The splicing needs some cross-fading to make the wrapping  
> less
> audioble or else that will dominate and by itself take attention  
> away from
> whatever else there might be there that we wanted to check.

At least we get a different pitch if the sample rate isn't an integer  
multiple of the waveform's frequency. Most samplers have a "loop fine  
tune" parameter to correct for this effect in one-cycle-loops.
I can't hear a pitch difference in Colin's example right now though,  
but at the moment it's quite noisy here. Have to try again when it's  
quiter.

Ingo