I had a go at converting a schroeder reverb I found on the max forums, but it sounds like repeated definitions of the allpass are sharing the same buffer or something (it’s giving a weird pitch shifter effect)
anyone have any tips?
(
~genDef = DynGenDef(\funcs,
"
function wrap(x, low, high)local(range, result)
(
range = high - low;
result = range != 0 ? (x - floor((x - low) / range) * range) : low;
result;
);
function mstosamps(ms)( srate * ms * 0.001 );
function linear_interp(x, y, a) ( x + a * (y-x));
function lpf_op_simple(in, damp) local(init, prev, lpf)(
lpf = linear_interp(in, prev, damp);
prev = lpf;
lpf;
);
function allpass_delay(in, gain, delay_samps, buf) local(init, ptr, max_delay, read_pos, frac, a, b, tap, sig, out)
(
!init ? (ptr = 0; init = 1;);
max_delay = mstosamps(3000);
read_pos = wrap(ptr - delay_samps, 0, max_delay);
frac = read_pos - floor(read_pos);
a = wrap(floor(read_pos), 0, max_delay);
b = wrap(a + 1, 0, max_delay);
tap = linear_interp(buf[a|0], buf[b|0], frac);
sig = (in - tap) * gain;
out = tap + sig;
buf[ptr] = sig;
ptr = wrap(ptr + 1, 0, max_delay);
out;
);
function fbcomb(in, gain, delay_samps, damp, buf) local(init, ptr, read_pos, max_delay, frac, a, b, tap, out)
(
!init ? (ptr = 0; init = 1;);
max_delay = mstosamps(3000);
read_pos = wrap(ptr - delay_samps, 0, max_delay);
frac = read_pos - floor(read_pos);
a = wrap(floor(read_pos), 0, max_delay);
b = wrap(a + 1, 0, max_delay);
tap = linear_interp(buf[a|0], buf[b|0], frac);
tap = lpf_op_simple(tap, damp);
out = (in - tap) * gain;
buf[ptr] = out;
ptr = wrap(ptr+1, 0, max_delay);
out;
);
size=in1; damp=in2;
ap1_buf[0]+=0;
ap2_buf[0]+=0;
ap3_buf[0]+=0;
sig = lpf_op_simple(in0, damp);
ap1 = allpass_delay(sig, 0.7, 347 * size, ap1_buf);
ap2 = allpass_delay(ap1, 0.7, 113 * size, ap2_buf);
ap3 = allpass_delay(ap2, 0.7, 370 * size, ap3_buf);
sig = ap3;
x1_buf[0]+=0;
x2_buf[0]+=0;
x3_buf[0]+=0;
x4_buf[0]+=0;
x1 = fbcomb(sig, 0.773, 1687, damp, x1_buf);
x2 = fbcomb(sig, 0.802, 1601, damp, x2_buf);
x3 = fbcomb(sig, 0.753, 2053, damp, x3_buf);
x4 = fbcomb(sig, 0.733, 2251, damp, x4_buf);
s1 = x1 + x3;
s2 = x2 + x4;
o1 = s1 + s2;
o2 = ((s1 + s2) * -1);
o3 = ((s1 - s2) * -1);
o4 = s1 - s2;
left=o1+o3;
right=o2+o4;
out0=left;
out1=right;
"
).send;
Ndef(\schroeder).clear;
Ndef(\schroeder, {
var test = Decay.ar(Impulse.ar(1), 0.25, LFCub.ar(1200, 0, 0.1));
var sig = DynGen.ar(2, ~genDef, test, 100, 0.5).sanitize;
sig;
});
Ndef(\schroeder).play;
);
)
