on 2013-09-12 at 22:22 Victor Lazzarini wrote:

> It looks a bit like aliasing, which I guess can happen depending on
> sizes of tables, and on parameters. Have you tried larger tables (>
> 16384) for both sine and sigmoid? Also your grain size is a bit small,
> did you try doubling it (0.04)?

hi victor and oeyvind, i tried all these suggestions but nothing changed
with respect to the problem i'm referring to. also the relation between
fundamental and formant frequencies has no effect that i can see. 

these are not aliases but rather like sub-harmonics, and the cause seems
to be the relation between grain rate and sample rate, as oeyvind
suggests. please compile the attached orchestra at 44100 and 48000 and you
should see that the spectrum is clean only when the sampling rate is a
multiple of the fundamental frequency. at least that's what i think to
detect.