diff --git a/src/core/sample_buffer.cpp b/src/core/sample_buffer.cpp
index 89d86d311..e0c62279c 100644
--- a/src/core/sample_buffer.cpp
+++ b/src/core/sample_buffer.cpp
@@ -159,7 +159,7 @@ sampleBuffer::~sampleBuffer()
 
 void sampleBuffer::update( bool _keep_settings )
 {
-	const bool lock = ( m_data == NULL );
+	const bool lock = ( m_data != NULL );
 	if( lock )
 	{
 		engine::getMixer()->lock();