decklyn wrote:Just open up a frequency analyser. A pure sine should be just a slit. If it takes up anymore frequency than that then there is harmonics.
FWIW, a perfect sine won't show up as a slit in a digital frequency analyzer. In a theoretical continuous system it would, but it's a feature of discrete fourier transforms (which I really should learn more about...) that that doesn't actually happen in the digital world.
I'm not 100% sure where I stand on this - I know that wavetable based algorithms aren't intrinsically identical to mathematical wave generation, but I'm not sure whether it's theoretically different in a way that is indistinguishable at real world digital resolutions or whether it actually makes an audible difference. Anyway, I was a bit bored this evening, so I chucked a bunch of waves from Synth1 (decent freebie synth but I'd be suprised if it had a particularly special sine wave oscillator) into audacity and stuck them next to some mathematically generated sines at the same pitches. Anyone want to pick out which is which?
* all in one wav file, 44k / 16 bit PCM
* The order is randomized for each of the 4 pairs, the pitches are from about G#1 down to B0.
* the lengths and fades in and out were done by hand in audacity - so they aren't identical but there won't be any clues to which is which in the attack / release phases
* the synth tones were generated with as close to an init setting as I could get, and then each was peak-normalized to -3dB. The mathematical sines were generated at 0dB and then turned down to -3dB.
https://www.yousendit.com/download/ZW9E ... MlZFQlE9PQ
Personally I'm not sure I can hear a difference. But I'm not listening on great speakers. Now I'm going to stick some halfstep beats over it and send it off to a label or two...