diff --git a/src/sound/saasound/SAAImpl.cpp b/src/sound/saasound/SAAImpl.cpp
index cb5d8f739..f136eefc6 100644
--- a/src/sound/saasound/SAAImpl.cpp
+++ b/src/sound/saasound/SAAImpl.cpp
@@ -306,6 +306,7 @@ void scale_for_output(unsigned int left_input, unsigned int right_input,
 void CSAASoundInternal::GenerateMany(BYTE* pBuffer, unsigned long nSamples)
 {
 	unsigned int left_mixed, right_mixed;
+	static double filterout_z1_left_mixed = 0, filterout_z1_right_mixed = 0;
 
 #if defined(DEBUGSAA) || defined(USE_CONFIG_FILE)
 	BYTE* pBufferStart = pBuffer;
diff --git a/src/sound/saasound/SAAImpl.h b/src/sound/saasound/SAAImpl.h
index 6cd3048fe..61fa79c58 100755
--- a/src/sound/saasound/SAAImpl.h
+++ b/src/sound/saasound/SAAImpl.h
@@ -36,8 +36,6 @@ private:
 	unsigned int m_nSampleRate;
 	unsigned int m_nOversample;
 	bool m_bHighpass;
-	double filterout_z1_left_mixed = 0;
-	double filterout_z1_right_mixed = 0;
 #ifdef USE_CONFIG_FILE
 	SAAConfig m_Config;
 #endif