Did you make it work in a patch? if so, can you share it? :) Maybe someone could work on a "fix" on the source and send it to miller, perhaps this could be updated for the next version release (0.47).
cheers 2015-11-22 19:32 GMT-02:00 Matt Barber <brbrof...@gmail.com>: > Yeah, so all that really needs to be done is to force symmetry by copying > the 0-pi phase inverted to the pi-2pi phase + guard points for [tabosc4~]. > I did that and it's been stable for 3.5 hours. It wouldn't be too hard to > fix this in the Pd source; it would be a marked improvement to [osc~] even > with the 512-pt table and linear interpolation. > > On Sun, Nov 22, 2015 at 12:43 PM, Matt Barber <brbrof...@gmail.com> wrote: > >> OK, subtracting out the DC is more stable, but still deteriorates after a >> bit, since the exact value likely changes with frequency due to >> interpolation. So the solution is going to have to be in writing the table. >> We can do it in Pd but we're hampered by the six-digit limit on specifying >> 2pi directly as a float. The most accurate pi I can think of for feeding >> through [cos] is [0 -1( -- [atan2]. [cos] uses the cosf() function from C, >> which expects floats instead of doubles, so hopefully the symmetry is >> better. I'm going to try it for a while and write back. >> >> Matt >> >> On Sun, Nov 22, 2015 at 11:16 AM, Roman Haefeli <reduz...@gmail.com> >> wrote: >> >>> On Sun, 2015-11-22 at 10:44 +0100, volker böhm wrote: >>> > hi, >>> > i think the timbre change in the FM example is due to a less than >>> ideal cosine wavetable which is used for osc~ (and cos~ etc.). >>> > the "cos_maketable(void)" in d_osc.c produces a waveform which is >>> slightly asymmetric, i.e. it has a tiny DC offset. >>> > this in return, causes the timbre shift when used in an FM context >>> (asymmetric FM). >>> > vb >>> >>> Well spotted. >>> >>> Roman >>> >>> _______________________________________________ >>> Pd-list@lists.iem.at mailing list >>> UNSUBSCRIBE and account-management -> >>> http://lists.puredata.info/listinfo/pd-list >>> >>> >> > > _______________________________________________ > Pd-list@lists.iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list > >
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