NO-OP: clarify maths
This commit is contained in:
parent
827be736ae
commit
b142fc4410
@ -168,10 +168,14 @@ Amp::apply_gain (BufferSet& bufs, samplecnt_t sample_rate, samplecnt_t nframes,
|
||||
return target;
|
||||
}
|
||||
|
||||
/* Apply Audio Gain first, calculate target LFP'ed gain coefficient
|
||||
/* Apply Audio Gain first, calculate 1 pole IIR time constant
|
||||
*
|
||||
* Low pass filter coefficient: 1.0 - e^(-2.0 * π * f / 48000) f in Hz.
|
||||
* for f << SR, approx a ~= 6.2 * f / SR;
|
||||
* H(z) = a / (1 - (1 - a) z^-1)
|
||||
* a = -y + sqrt (y^2 + 2y); y = 1 - cos (w) ; w = 2 * π f/SR
|
||||
* a ~= 1.0 - e^(-2.0 * π * f / SR)
|
||||
*
|
||||
* and for very small w (f << SR)
|
||||
* a ~= 6.2 * f / SR;
|
||||
*/
|
||||
const gain_t a = 156.825f / (gain_t)sample_rate; // 25 Hz LPF
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user