diff --git a/ChangeLog b/ChangeLog
index 465cebeb79..e08c0687a6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2008-03-01	Tobias Doerffel	<tobydox/at/users/dot/sourceforge/dot/net>
 
+	* plugins/patman/patman.cpp:
+	do not crash in patmanInstrument::playNote() when no file is set
+
+	* include/ladspa_control.h:
+	* src/core/ladspa_control.cpp:
+	fixed missing tempoSyncKnobModel for not crashing when instantiating
+	LADSPA-plugins with time-knobs inside
+
+	* src/lib/sample_buffer.cpp:
+	do not set global mixer lock in update() if no data has been set yet
+
 	* plugins/patman/patman.cpp:
 	do not crash when loading settings where no file is set
 
diff --git a/src/lib/sample_buffer.cpp b/src/lib/sample_buffer.cpp
index 6d3a2a69c1..fe963f934e 100644
--- a/src/lib/sample_buffer.cpp
+++ b/src/lib/sample_buffer.cpp
@@ -122,9 +122,12 @@ sampleBuffer::sampleBuffer( const sampleFrame * _data, const f_cnt_t _frames ) :
 	m_sample_rate( SAMPLE_RATES[DEFAULT_QUALITY_LEVEL] ),
 	m_sample_fragment( NULL )
 {
-	m_origData = new sampleFrame[_frames];
-	memcpy( m_origData, _data, _frames * BYTES_PER_FRAME );
-	m_origFrames = _frames;
+	if( _frames > 0 )
+	{
+		m_origData = new sampleFrame[_frames];
+		memcpy( m_origData, _data, _frames * BYTES_PER_FRAME );
+		m_origFrames = _frames;
+	}
 #ifdef SDL_SDL_SOUND_H
 	// init sound-file-system of SDL
 	Sound_Init();
@@ -152,9 +155,12 @@ sampleBuffer::sampleBuffer( const f_cnt_t _frames ) :
 	m_sample_rate( SAMPLE_RATES[DEFAULT_QUALITY_LEVEL] ),
 	m_sample_fragment( NULL )
 {
-	m_origData = new sampleFrame[_frames];
-	memset( m_origData, 0, _frames * BYTES_PER_FRAME );
-	m_origFrames = _frames;
+	if( _frames > 0 )
+	{
+		m_origData = new sampleFrame[_frames];
+		memset( m_origData, 0, _frames * BYTES_PER_FRAME );
+		m_origFrames = _frames;
+	}
 #ifdef SDL_SDL_SOUND_H
 	// init sound-file-system of SDL
 	Sound_Init();
@@ -180,9 +186,12 @@ sampleBuffer::~sampleBuffer()
 
 void sampleBuffer::update( bool _keep_settings )
 {
-	engine::getMixer()->lock();
-
-	delete[] m_data;
+	const bool lock = ( m_data == NULL );
+	if( lock )
+	{
+		engine::getMixer()->lock();
+		delete[] m_data;
+	}
 
 	if( m_audioFile == "" && m_origData != NULL && m_origFrames > 0 )
 	{
@@ -301,7 +310,10 @@ m_data[frame][chnl] = buf[idx] * fac;
 		m_loop_endFrame = m_endFrame = 1;
 	}
 
-	engine::getMixer()->unlock();
+	if( lock )
+	{
+		engine::getMixer()->unlock();
+	}
 
 	emit sampleUpdated();
 }