AP2
2nd order ALLPASS biquad filter with resonance at 0 (=equal slope). LP-HP
Inlets
frac32buffer input
frac32 cutoff frequency
Outlets
frac32buffer output
Parameters
frac32.s.map.pitch freq
Declaration
biquad_state bsl;
biquad_coefficients bcl;
biquad_state bsh;
biquad_coefficients bch;
int32_t tmp[BUFSIZE];
Init
biquad_clearstate(&bsl);
biquad_clearstate(&bsh);
Control Rate
int32_t f;
MTOF(param_freq + inlet_freq, f);
biquad_hp_coefs(&bch, f, INT_MAX);
biquad_lp_coefs(&bcl, f, INT_MAX);
biquad_dsp(&bsh, &bch, inlet_in, tmp);
biquad_dsp(&bsl, &bcl, inlet_in, outlet_out);
for (int i = 0; i < BUFSIZE; i++) {
outlet_out[i] -= tmp[i];
}