+++ /dev/null
-declare name "lfboost";
-declare version "1.0";
-declare author "Grame";
-declare license "BSD";
-declare copyright "(c)GRAME 2006";
-
-//------------------------------------------------------------------
-// DAFX, Digital Audio Effects (Wiley ed.)
-// chapter 2 : filters
-// section 2.3 : Equalizers
-// page 53 : second order shelving filter design
-//------------------------------------------------------------------
-
-import("math.lib");
-import("music.lib");
-
-
-//----------------------low frequency boost filter -------------------------------
-// lfboost(F,G)
-// F : frequency (in Hz)
-// G : gain (in dB)
-//
-//--------------------------------------------------------------------------------
-
-lfboost(F,G) = TF2( (1 + sqrt(2*V)*K + V*K*K) / denom,
- 2 * (V*K*K - 1) / denom,
- (1 - sqrt(2*V)*K + V*K*K) / denom,
- 2 * (K*K - 1) / denom,
- (1 - sqrt(2)*K + K*K) / denom
- )
- with {
- V = db2linear(G);
- K = tan(PI*F/SR);
- denom = 1 + sqrt(2)*K + K*K;
- };
-
-
-
-//====================low frequency boost process ===============================
-
-process = vgroup("lowboost", lfboost(
- nentry("freq (Hz)", 100, 20, 150, 1),
- vslider("gain (dB)", 0, -20, 20, 0.1)
- ) );