+++ /dev/null
-declare name "lowboost";
-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("music.lib");
-
-
-//------------------- low-frequency shelving boost (table 2.3) --------------------
-
-V0(g) = pow(10,g/20.0);
-K(fc) = tan(PI*fc/SR);
-square(x) = x*x;
-denom(fc) = 1 + sqrt(2)*K(fc) + square(K(fc));
-
-lfboost(fc, g) = TF2( (1 + sqrt(2*V0(g))*K(fc) + V0(g)*square(K(fc))) / denom(fc),
- 2 * (V0(g)*square(K(fc)) - 1) / denom(fc),
- (1 - sqrt(2*V0(g))*K(fc) + V0(g)*square(K(fc))) / denom(fc),
- 2 * (square(K(fc)) - 1) / denom(fc),
- (1 - sqrt(2)*K(fc) + square(K(fc))) / denom(fc)
- );
-
-
-//------------------------------ User Interface -----------------------------------
-
-freq = hslider("[1]freq [unit:Hz][style:knob]", 1000, 20, 20000, 0.1);
-gain = hslider("[2]gain [unit:dB][style:knob]", 0, -20, 20, 0.1);
-
-
-//----------------------------------- Process -------------------------------------
-
-process = vgroup("low-freq shelving boost", lfboost(freq,gain));
-