relax gain LPF to 25Hz.

diff --git a/libs/ardour/amp.cc b/libs/ardour/amp.cc
index caf00dc4964ad082d07c3d238ee6b160838376c4..07f79ed5a89c402fd5d0ed77aa1f0566f566797e 100644 (file)
--- a/libs/ardour/amp.cc
+++ b/libs/ardour/amp.cc
@@ -107,7 +107,7 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
                        }
 
 
-                       const double a = 62.78 / _session.nominal_frame_rate(); // 10 Hz LPF; see Amp::apply_gain for details
+                       const double a = 156.825 / _session.nominal_frame_rate(); // 25 Hz LPF; see Amp::apply_gain for details
                        double lpf = _current_gain;
 
                        for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
@@ -210,7 +210,7 @@ Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, ga
        /* Low pass filter coefficient: 1.0 - e^(-2.0 * π * f / 48000) f in Hz.
         * for f << SR,  approx a ~= 6.2 * f / SR;
         */
-       const double a = 62.78 / sample_rate; // 10 Hz LPF
+       const double a = 156.825 / sample_rate; // 25 Hz LPF
 
        for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                Sample* const buffer = i->data();
@@ -289,7 +289,7 @@ Amp::apply_gain (AudioBuffer& buf, framecnt_t sample_rate, framecnt_t nframes, g
        }
 
         Sample* const buffer = buf.data();
-       const double a = 62.78 / sample_rate; // 10 Hz LPF, see  [other] Amp::apply_gain() above,
+       const double a = 156.825 / sample_rate; // 25 Hz LPF, see [other] Amp::apply_gain() above for details
 
        double lpf = initial;
         for (pframes_t nx = 0; nx < nframes; ++nx) {