[music-dsp] wavetable and aliasing (Again)
P.Maddox at signal.qinetiq.com
Wed Apr 30 01:36:00 EDT 2003
> A whole phase? That'd imply B's precise waveform wouldn't matter at all. I
> just can't bring myself to believe that is the case. One version I've
> heard of is, A syncs to B upon B's crossing zero. Is that really just a
It depends on the oscillator.
usually a sync pulse is sent (if the osc has a sync out) at the start of
so ONCE a phase ou get a sync pulse out.
imagine if you wanted to use two analogue oscillators, one an octave below
Osc A = Sawtooth
Osc B = sine (an octave down)
the one an octave down would have a sinewave, the one above would have a
sawtooth, the resultant sound would be a thicker sounding sawtooth, BUT to
get it to sound right you need to lock both oscillators starts together
(phasing can thin the sound a little). with analogue oscillators you cannot
get two different circuits to be exactly in sync with each other. So you
would take the sync out from OscB into OscA, this would ensure that the two
always tracked the same pitch and stayed in sync with each other.
> Whatever the deal is, there is also the difference between hard an soft
> sync. As I've heard the tale told, "hard" means "reset to the beginning of
> the cycle" while "soft" means "flip polarity". Am I getting this anywhere
> in the vicinity of things Right and True?
soft sync has different meanings on different synths sadly..
on some synths it does as you say.
On most of the older ones Soft sync pulls the waveform back to the start but
only for the time the sync in pulse is high....
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