checking Csound's fof opcode, formant really seems like a version of it

2017-04-14 1:55 GMT-03:00 Alexandre Torres Porres <porres@gmail.com>:

BTW, here's an excerpt from Formant's code, found in here from line 2451 

LOOP1(inNumSamples,

if (phase3 < onecyc13) {

ZXP(out) = (*(float*)((char*)sine + (((phase3 + tqcyc13) >> xlobits) & xlomask13)) + 1.f)

        *  *(float*)((char*)sine + ((phase2 >> xlobits) & xlomask13));

phase3 += formfreq;

} else {

ZXP(out) = 0.f;

}

phase1 += freq1;

phase2 += freq2;

if (phase1 > onecyc13) {

phase1 -= onecyc13;

phase2 = phase1 * freq2 / freq1;

phase3 = phase1 * freq3 / freq1;

}

);

2017-04-13 21:15 GMT-03:00 Alexandre Torres Porres <porres@gmail.com>:

2017-04-13 19:25 GMT-03:00 JTG III <jordanthomasgibbonsiii@gmail.com>:

Chant was the program that implemented Fof synthesis, both developed at IRCAM in the late 70's/early 80's or thereabouts.
I haven't used SC in a long time, and now I'm unsure about those ugens.
Also, a quick search for anything on the "filter version"  of FOF didn't seem to bring anything up, but there's an article in this anthology of early eighties Computer Music Journal articles that I have at home which at least mentions it, I think. I can check when I get home, or you can find it on Sci-Hub.

"Formlet", the "FOF-like filter", is just a resonant filter with an attack/decay envelope. I was able to replicate it. Though I get the idea that the fof-filter thingy is based on a bank of such filters, huh? "Formant", on the other hand, is described as an "oscillator", it "generates a set of harmonics around a formant frequency at a given fundamental frequency", has parameters for fundamental frequency, formant frequency and bandwidth of the formant frequency. 

I'm really curious on how to implement it as a pd patch ;) - but I don't think I've seen anything like it in the Pd world.

cheers