bar

Files: bar.h, bar.c

Physical model approximating the sound of a struck metal bar

Functions

sp_bar_create(sp_bar **bar)
sp_bar_init(sp_data *sp, sp_bar *bar, SPFLOAT iK, SPFLOAT ib)
sp_bar_compute(sp_data *sp, sp_bar *bar, SPFLOAT *trig, SPFLOAT *out)
sp_bar_destroy(sp_bar **bar)

Mandatory Parameters

iK: Dimensionless stiffness parameter
(Recommended value: 3)
ib: High-frequency loss parameter. Keep this small
(Recommended value: 0.001)

Optional Parameters

bcL: Boundary condition at left end of bar. 1 = clamped, 2 = pivoting, 3 = free
(Default value: 1)
bcR: Boundary condition at right end of bar. 1 = clamped, 2 = pivoting, 3 = free
(Default value: 1)
T30: 30db decay time (in seconds).
(Default value: 3)
scan: Speed of scanning the output location.
(Default value: 0.25)
pos: Position along bar that strike occurs.
(Default value: 0.2)
vel: Normalized strike velocity
(Default value: 500)
wid: Spatial width of strike.
(Default value: 0.05)

Inputs

trig: Non-zero values will strike the bar.

Outputs

out: Signal output.

Example Code

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

typedef struct {
    sp_bar *bar;
    sp_metro *met;
} UserData;

void process(sp_data *sp, void *udata) {
    UserData *ud = udata;
    SPFLOAT bar = 0, met = 0;
    sp_metro_compute(sp, ud->met, NULL, &met);
    sp_bar_compute(sp, ud->bar, &met, &bar);
    sp->out[0] = bar;
}

int main() {
    srand(1234567);
    UserData ud;
    sp_data *sp;
    sp_create(&sp);

    sp_bar_create(&ud.bar);
    sp_metro_create(&ud.met);

    sp_bar_init(sp, ud.bar, 3, 0.0001);
    ud.bar->T30 = 1;

    sp_metro_init(sp, ud.met);
    ud.met->freq = 1;

    sp->len = 44100 * 5;
    sp_process(sp, &ud, process);

    sp_bar_destroy(&ud.bar);
    sp_metro_destroy(&ud.met);

    sp_destroy(&sp);
    return 0;
}