Nyquist (pronounce it like Klopstock!)

diff --git a/libs/ardour/dsp_filter.cc b/libs/ardour/dsp_filter.cc
index 0eef61a0f4b5a032fe2f346662e724f522ad1d3f..d1aa6cd9aeca1d2cc0b9220e845dc7c45b653945 100644 (file)
--- a/libs/ardour/dsp_filter.cc
+++ b/libs/ardour/dsp_filter.cc
@@ -197,9 +197,9 @@ Biquad::configure (double a1, double a2, double b0, double b1, double b2)
 void
 Biquad::compute (Type type, double freq, double Q, double gain)
 {
-       if (Q <= .001)     { Q = 0.001; }
-       if (freq <= 1.)    { freq = 1.; }
-       if (freq >= _rate) { freq = _rate; }
+       if (Q <= .001)  { Q = 0.001; }
+       if (freq <= 1.) { freq = 1.; }
+       if (freq >= 0.4998 * _rate) { freq = 0.4998 * _rate; }
 
        /* Compute biquad filter settings.
         * Based on 'Cookbook formulae for audio EQ biquad filter coefficents'