[sdiy] Harmonic bandwidth

[Ben Lincoln]

I would think that in an actual acoustic instrument, the phases for the 
various harmonic components aren't random, but that they are extremely 
complicated to the point that randomizing the phases of the harmonics in 
an additive synth might give a very similar effect without the extensive 
processing to accurately simulate all of the various resonating parts of 
an acoustic instrument.
How's that for a run-on sentence full of qualifications and assumptions 
and low on facts?
Anyway, if I make the further assumption that that theory is accurate, I 
would think it would be more useful to use some sort of model for 
altering the phases of the harmonics in a complicated, but non-random 
way (so that the effect can be tuned and is reproducible). Sort of like 
a meta-additive synth - you'd have controls for both the amplitude *and* 
phase of each sine wave, and some way of modulating them in an 
interesting way - to bring in another discussion from the list, maybe a 
scanner that would loop through the phase controls and set each one 
based on the state of an LFO.

Ian Fritz wrote:
> I'm especially unclear on "Put random phases to each frequency of the 
> spectrum".  Is this really how acoustic instruments work? It's true 
> that nonlinearities can introduce anharmonicities, as in piano 
> strings, but I don't see how this leads to random phases.