diff --git a/include/lmms_math.h b/include/lmms_math.h
index 43f699718..ea13f94b7 100644
--- a/include/lmms_math.h
+++ b/include/lmms_math.h
@@ -34,10 +34,6 @@
 #include <cmath>
 using namespace std;
 
-#ifndef M_PI
-#	define M_PI 3.14159265358979323846
-#endif
-
 #if defined (LMMS_BUILD_WIN32) || defined (LMMS_BUILD_APPLE) 
 #ifndef isnanf
 #define isnanf(x)	isnan(x)
diff --git a/src/core/fft_helpers.cpp b/src/core/fft_helpers.cpp
index 0f9444aa6..71e84a8db 100644
--- a/src/core/fft_helpers.cpp
+++ b/src/core/fft_helpers.cpp
@@ -25,7 +25,7 @@
 
 #include "fft_helpers.h"
 
-#include <lmms_math.h>
+#include "lmms_math.h"
 
 
 /* returns biggest value from abs_spectrum[spec_size] array
@@ -73,7 +73,7 @@ int hanming(float *timebuffer, int length, WINDOWS type)
 	
 	for ( i=0; i<length; i++ )
 	{
-		timebuffer[i]=timebuffer[i]*(alpha+(1-alpha)*cos(2*M_PI*i/((float)length-1.0)));
+		timebuffer[i]=timebuffer[i]*(alpha+(1-alpha)*cos(2*F_PI*i/((float)length-1.0)));
 	}	
 
 	return 0;
diff --git a/src/gui/widgets/knob.cpp b/src/gui/widgets/knob.cpp
index 96b40a22f..33987b263 100644
--- a/src/gui/widgets/knob.cpp
+++ b/src/gui/widgets/knob.cpp
@@ -305,7 +305,7 @@ void knob::setarcColor( const QColor & _c )
 
 QLineF knob::calculateLine( const QPointF & _mid, float _radius, float _innerRadius ) const
 {
-	const float rarc = m_angle * M_PI / 180.0;
+	const float rarc = m_angle * F_PI / 180.0;
 	const float ca = cos( rarc );
 	const float sa = -sin( rarc );