[sdiy] Analysis of frequency variation in analogue synths

[Andre Majorel]

On 2007-05-03 12:39 +0100, Colin f wrote:

> Take an analogue synth, and record several seconds of bare
> oscillator sound into an audio app of your choice, through a
> half decent audio interface.  Now take a single cycle of that
> waveform, and create a new file by pasting the single cycle
> repeatedly until you end up with the same length of sample as
> the original recording.
>
> http://www.colinfraser.com/misc/mini-saw-alternate.mp3
>
> 1 minute or each wave, with a short gap between. Play it in a
> loop, turn down the volume, hide the audio app window so you
> can't see which point you're at in the file, then go away for a
> random period of time.  When you return, you'll have no
> preconception of which wave you're listening to, so it should be
> an accurate test of whether you can detect the analogueness of
> the real VCO.
> 
> In isolation, can you tell the two waves apart ?

Yes.

> If you can, how long do you need to listen to the waves to
> decide which is analogue and which is 'digital' ?

I can't. One is less stable than the other so I imagine it's the
analogue one but I wouldn't say either sounds "analogue" or
"digital" or "un-analogue". An unfiltered static sawtooth is not a
sound I like, analogue or not.

> But if I can't hear any extra 'analogueness' in the raw
> oscillator compared to a single-cycle sample of it for the
> typical duration of a note played on the synth, surely that
> means other factors have a much more important influence on
> analogueness than oscillator jitter ?

Or the analogueness only appears when all of those factors are
present. I do know that DCO synths tend to sound worse to me.

Thanks, that was an interesting test.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
Do not use this account for regular correspondence.
See the URL above for contact information.