tbvcf
Files: tbvcf.h, tbvcf.c

Emulation of the Roland TB-303 filter

Functions

sp_tbvcf_create(sp_tbvcf **tbvcf)
sp_tbvcf_init(sp_data *sp, sp_tbvcf *tbvcf)
sp_tbvcf_compute(sp_data *sp, sp_tbvcf *tbvcf, SPFLOAT *input, SPFLOAT *out)
sp_tbvcf_destroy(sp_tbvcf **tbvcf)

Optional Parameters

fco: Filter cutoff frequency
(Default value: 500)
res: Resonance
(Default value: 0.8)
dist: Distortion. Value is typically 2.0; deviation from this can cause stability issues.
(Default value: 2.0)
asym: Asymmetry of resonance. Value is between 0-1
(Default value: 0.5)

Inputs

input: Signal input.

Outputs

out: Signal output.

Example Code

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include "soundpipe.h"

typedef struct {
    sp_noise *ns;
    sp_tbvcf *tn;
} UserData;

void write_noise(sp_data *sp, void *udata) {
    UserData *ud = udata;
    SPFLOAT in = 0;
    SPFLOAT out = 0;
    sp_noise_compute(sp, ud->ns, NULL, &in);
    sp_tbvcf_compute(sp, ud->tn, &in, &sp->out[0]); 
}
int main() {
    srand(time(NULL));
    UserData ud;
    sp_data *sp;
    sp_create(&sp);
    sp_noise_create(&ud.ns);
    sp_tbvcf_create(&ud.tn);
    sp_noise_init(sp, ud.ns);
    sp_tbvcf_init(sp, ud.tn);
    sp->len = 44100 * 5;
    ud.tn->dist = 1.0;
    sp_process(sp, &ud, write_noise);
    sp_noise_destroy(&ud.ns);
    sp_tbvcf_destroy(&ud.tn);
    sp_destroy(&sp);
    return 0;
}