diff --git a/ChangeLog b/ChangeLog
index f4a813f9f..c589e5979 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,23 @@
 2008-04-03	Tobias Doerffel	<tobydox/at/users/dot/sourceforge/dot/net>
 
+	* include/song.h:
+	* src/core/song.cpp:
+	* src/gui/export_project_dialog.cpp:
+	* src/gui/song_editor.cpp:
+	made song-length being cached and only updated upon changed length or
+	position of TCOs
+
+	* src/core/track.cpp:
+	optimized track::length()-method
+
+	* src/core/mixer.cpp:
+	great improvements on multithreading - one global job-queue protected by
+	a simple mutex where threads pull their jobs from
+
+	* src/core/engine.cpp:
+	delete LADSPA-manager after mixer and FX-mixer as LADSPA-effects in
+	FX-mixer access LADSPA-manger at destruction
+
 	* plugins/ladspa_effect/ladspa_effect.cpp:
 	* plugins/ladspa_effect/ladspa_effect.h:
 	* plugins/bass_booster/bass_booster.cpp:
diff --git a/include/song.h b/include/song.h
index 86e7d1286..e5152404f 100644
--- a/include/song.h
+++ b/include/song.h
@@ -112,8 +112,7 @@ public:
 	inline bool exportDone( void ) const
 	{
 		return( m_exporting == TRUE &&
-			m_playPos[Mode_PlaySong].getTact() >=
-							lengthInTacts() + 1 );
+			m_playPos[Mode_PlaySong].getTact() >= length() + 1 );
 	}
 
 	inline PlayModes playMode( void ) const
@@ -126,7 +125,11 @@ public:
 		return( m_playPos[_pm] );
 	}
 
-	tact lengthInTacts( void ) const;
+	void updateLength( void );
+	tact length( void ) const
+	{
+		return( m_length );
+	}
 
 
 	bpm_t getTempo( void );
@@ -211,7 +214,6 @@ private:
 		return( m_playPos[m_playMode].getTact() );
 	}
 
-	midiTime length( void ) const;
 	inline tact64th currentTact64th( void ) const
 	{
 		return( m_playPos[m_playMode].getTact64th() );
@@ -240,6 +242,7 @@ private:
 
 	PlayModes m_playMode;
 	playPos m_playPos[Mode_Count];
+	tact m_length;
 
 	track * m_trackToPlay;
 	pattern * m_patternToPlay;
diff --git a/src/core/song.cpp b/src/core/song.cpp
index 4f6c9a1ae..184254937 100644
--- a/src/core/song.cpp
+++ b/src/core/song.cpp
@@ -538,15 +538,18 @@ void song::playPattern( pattern * _patternToPlay, bool _loop )
 
 
 
-tact song::lengthInTacts( void ) const
+void song::updateLength( void )
 {
-	tact len = 0;
+	m_length = 0;
 	const QList<track *> & ctl = tracks();
 	for( int i = 0; i < ctl.size(); ++i )
 	{
-		len = tMax( ctl[i]->length(), len );
+		const tact cur = ctl[i]->length();
+		if( cur > m_length )
+		{
+			m_length = cur;
+		}
 	}
-	return( len );
 }
 
 
diff --git a/src/gui/export_project_dialog.cpp b/src/gui/export_project_dialog.cpp
index 0946b24d8..cd95643cf 100644
--- a/src/gui/export_project_dialog.cpp
+++ b/src/gui/export_project_dialog.cpp
@@ -370,8 +370,8 @@ void exportProjectDialog::exportBtnClicked( void )
 							&& !m_deleteFile )
 	{
 		dev->processNextBuffer();
-		int pval = pp * 100 /
-			( ( engine::getSong()->lengthInTacts() + 1 ) * 64 );
+		const int pval = pp * 100 /
+				( ( engine::getSong()->length() + 1 ) * 64 );
 		m_exportProgressBar->setValue( pval );
 		if( engine::getMainWindow() )
 		{
diff --git a/src/gui/song_editor.cpp b/src/gui/song_editor.cpp
index de293bd25..5ac71683b 100644
--- a/src/gui/song_editor.cpp
+++ b/src/gui/song_editor.cpp
@@ -378,7 +378,7 @@ songEditor::~songEditor()
 
 void songEditor::paintEvent( QPaintEvent * _pe )
 {
-	m_leftRightScroll->setMaximum( m_s->lengthInTacts() );
+	m_leftRightScroll->setMaximum( m_s->length() );
 	trackContainerView::paintEvent( _pe );
 }