On Tue, Mar 19, 2013 at 04:26:21AM +0100, Tim Goetze
wrote:
A 2nd-order IIR filter is often called a
"biquad"; at musicdsp, look
for that instead.
Not really. A biquad is one way to implement a 2nd order IIR, and
in many cases related to audio DSP, not really the best way.
Anyway, using a biquad for something so simple is giant overkill.
// Else run the filter:
for (i = 0; i < nframes; i++)
{
g1 += w * (gt - g1 - a * g2);
g2 += w * (b * g1 - g2);
out [i] = g2 * in [i];
}
Surely you realise this version executes exactly as many additions and
multiplications per sample as a biquad?