diff --git a/include/basic_filters.h b/include/basic_filters.h
index 2462978ee..e41046e61 100644
--- a/include/basic_filters.h
+++ b/include/basic_filters.h
@@ -69,7 +69,7 @@ public:
 
 	static inline float minFreq()
 	{
-		return( 0.01f );
+		return( 3.0f );
 	}
 
 	static inline float minQ()
@@ -488,8 +488,9 @@ public:
 				/*, const bool _q_is_bandwidth = false*/ )
 	{
 		// temp coef vars
-		_freq = qMax( _freq, minFreq() );// limit freq and q for not getting
-					      // bad noise out of the filter...
+		_freq = qBound(minFreq(), _freq, 20000.0f); // limit freq and q for not getting
+                                                            // bad noise out of the filter...
+
 		_q = qMax( _q, minQ() );
 
 		if( m_type == Lowpass_RC12  ||