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diff --git a/lib/reverb/dsp/Sine.h b/lib/reverb/dsp/Sine.h
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+/*
+	dsp/Sine.h
+	
+	Copyright 2003-13 Tim Goetze <tim@quitte.de>
+	
+	http://quitte.de/dsp/
+
+	Direct form I recursive sin() generator.  Utilising doubles 
+	for stability.
+
+*/
+/*
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 3
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to the Free Software
+	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+	02111-1307, USA or point your web browser to http://www.gnu.org.
+*/
+
+#ifndef _DSP_SINE_H_
+#define _DSP_SINE_H_
+
+namespace DSP {
+	
+class Sine
+{
+	public:
+		int z;
+		double y[2];
+		double b;
+
+	public:
+		Sine()
+			{ 
+				b = 0;
+				y[0] = y[1] = 0;
+				z = 0;
+			}
+
+		Sine (double f, double fs, double phase)
+			{
+				set_f (f, fs, phase);
+			}
+
+		Sine (double w, double phase = 0.)
+			{
+				set_f (w, phase);
+			}
+
+		inline void set_f (double f, double fs, double phase)
+			{
+				set_f (f*2*M_PI/fs, phase);
+			}
+
+		inline void set_f (double w, double phase)
+			{
+				b = 2 * cos (w);
+				y[0] = sin (phase - w);
+				y[1] = sin (phase - w * 2);
+				z = 0;
+			}
+
+		/* advance and return 1 sample */
+		inline double get()
+			{
+				register double s = b * y[z]; 
+				z ^= 1;
+				s -= y[z];
+				return y[z] = s;
+			}
+
+		double get_phase()
+			{
+				double x0 = y[z], x1 = b * y[z] - y[z^1];
+				double phi = asin (x0);
+				
+				/* slope is falling, we're into the 2nd half. */
+				if (x1 < x0)
+					return M_PI - phi;
+
+				return phi;
+			}
+};
+
+/* same as above but including a damping coefficient d */
+class DampedSine
+: public Sine
+{
+	public:
+		double d;
+
+	public:
+		DampedSine()
+			{ d = 1; }
+
+		inline double get()
+			{
+				register double s = b * y[z]; 
+				z ^= 1;
+				s -= d * y[z];
+				return y[z] = d * s;
+			}
+};
+
+} /* namespace DSP */
+
+#endif /* _DSP_SINE_H_ */