diff --git a/Timeline/Disk_Stream.C b/Timeline/Disk_Stream.C
index 57b389b..b2611f4 100644
--- a/Timeline/Disk_Stream.C
+++ b/Timeline/Disk_Stream.C
@@ -52,7 +52,6 @@ size_t Disk_Stream::disk_io_kbytes = 256;
 
 Disk_Stream::Disk_Stream ( Track *track, float frame_rate, nframes_t nframes, int channels ) : _track( track )
 {
-
     assert( channels );
 
     _frame = 0;
@@ -60,20 +59,9 @@ Disk_Stream::Disk_Stream ( Track *track, float frame_rate, nframes_t nframes, in
     _terminate = false;
     _pending_seek = -1;
     _xruns = 0;
+    _frame_rate = frame_rate;
 
-    _total_blocks = frame_rate * seconds_to_buffer / nframes;
-
-    _nframes = nframes;
-
-    size_t bufsize = _total_blocks * nframes * sizeof( sample_t );
-
-    if ( disk_io_kbytes )
-        _disk_io_blocks = ( bufsize * channels ) / ( disk_io_kbytes * 1024 );
-    else
-        _disk_io_blocks = 1;
-
-    for ( int i = channels; i--; )
-        _rb.push_back( jack_ringbuffer_create( bufsize ) );
+    _resize_buffers( nframes, channels );
 
     sem_init( &_blocks, 0, _total_blocks );
 }
@@ -97,14 +85,13 @@ Disk_Stream::~Disk_Stream ( )
 /* THREAD: RT */
 /** flush buffers and reset. Must only be called from the RT thread. */
 void
-Disk_Stream::flush ( bool is_output )
+Disk_Stream::base_flush ( bool is_output )
 {
 
     /* flush buffers */
-    for ( int i = channels(); i--; )
+    for ( int i = _rb.size(); i--; )
         jack_ringbuffer_read_advance( _rb[ i ], jack_ringbuffer_read_space( _rb[ i ] ) );
 
-
 /*  sem_destroy( &_blocks ); */
 
 /*     if ( is_output ) */
@@ -114,7 +101,6 @@ Disk_Stream::flush ( bool is_output )
 
     if ( is_output )
     {
-
         int n;
         sem_getvalue( &_blocks, &n );
 
@@ -145,6 +131,7 @@ Disk_Stream::shutdown ( void )
     if ( _thread )
         pthread_join( _thread, NULL );
 
+    _thread = 0;
     _terminate = false;
 }
 
@@ -168,12 +155,50 @@ Disk_Stream::run ( void )
         FATAL( "Could not create IO thread!" );
 }
 
+void
+Disk_Stream::_resize_buffers ( nframes_t nframes, int channels )
+{
+    for ( int i = _rb.size(); i--; )
+        jack_ringbuffer_free( _rb[ i ] );
+
+    _rb.clear();
+
+    _nframes = nframes;
+
+    _total_blocks = _frame_rate * seconds_to_buffer / nframes;
+
+    size_t bufsize = _total_blocks * nframes * sizeof( sample_t );
+
+    if ( disk_io_kbytes )
+        _disk_io_blocks = ( bufsize * channels ) / ( disk_io_kbytes * 1024 );
+    else
+        _disk_io_blocks = 1;
+
+    for ( int i = channels; i--; )
+        _rb.push_back( jack_ringbuffer_create( bufsize ) );
+}
+
+/* THREAD: RT (non-RT)  */
 /* to be called when the JACK buffer size changes. */
 void
-Disk_Stream::resize ( nframes_t nframes )
+Disk_Stream::resize_buffers ( nframes_t nframes )
 {
     if ( nframes != _nframes )
-        /* FIXME: to something here! */;
+    {
+        DMESSAGE( "resizing buffers" );
+
+        const bool was_running = _thread;
+
+        if ( was_running )
+            shutdown();
+
+        flush();
+
+        _resize_buffers( nframes, channels() );
+
+        if ( was_running )
+            run();
+    }
 }
 
 
diff --git a/Timeline/Disk_Stream.H b/Timeline/Disk_Stream.H
index 2f78e5c..871a06c 100644
--- a/Timeline/Disk_Stream.H
+++ b/Timeline/Disk_Stream.H
@@ -59,6 +59,9 @@ protected:
     int _total_blocks; /* total number of blocks that we can  buffer */
     int _disk_io_blocks; /* the number of blocks to read/write to/from disk at once */
 
+
+    nframes_t _frame_rate;      /* used for buffer size calculations */
+
     volatile nframes_t _pending_seek; /* absolute transport position to seek to */
     volatile int _terminate;
 
@@ -71,6 +74,8 @@ protected:
 
     static void *disk_thread ( void *arg );
 
+    void _resize_buffers ( nframes_t nframes, int channels );
+
 protected:
 
     void block_processed ( void ) { sem_post( &_blocks ); }
@@ -86,7 +91,8 @@ protected:
 
     virtual void disk_thread ( void ) = 0;
 
-    void flush ( bool is_output );
+    void base_flush ( bool is_output );
+    virtual void flush ( void ) = 0;
 
 public:
 
@@ -100,7 +106,7 @@ public:
 
     virtual ~Disk_Stream ( );
 
-    void resize ( nframes_t nframes );
+    void resize_buffers ( nframes_t nframes );
 
 /*     void seek ( nframes_t frame ); */
 /*     bool seek_pending ( void ); */
diff --git a/Timeline/Engine.C b/Timeline/Engine.C
index 84131fc..2d8f582 100644
--- a/Timeline/Engine.C
+++ b/Timeline/Engine.C
@@ -70,6 +70,12 @@ Engine::freewheel ( int starting, void *arg )
     ((Engine*)arg)->freewheel( starting );
 }
 
+int
+Engine::buffer_size ( nframes_t nframes, void *arg )
+{
+    return ((Engine*)arg)->buffer_size( nframes );
+}
+
 
 
 void
@@ -101,6 +107,16 @@ Engine::freewheel ( bool starting )
         DMESSAGE( "leaving freewheeling mode" );
 }
 
+/* THREAD: RT (non-RT) */
+int
+Engine::buffer_size ( nframes_t nframes )
+{
+    /* TODO: inform all disktreams the the buffer size has changed */
+    timeline->resize_buffers( nframes );
+
+    return 0;
+}
+
 /* THREAD: RT */
 /** This is the jack slow-sync callback. */
 int
@@ -232,6 +248,7 @@ Engine::init ( void )
     set_callback( process );
     set_callback( xrun );
     set_callback( freewheel );
+    set_callback( buffer_size );
 
     /* FIXME: should we wait to register this until after the project
      has been loaded (and we have disk threads running)? */
diff --git a/Timeline/Engine.H b/Timeline/Engine.H
index ba2c061..d21e36a 100644
--- a/Timeline/Engine.H
+++ b/Timeline/Engine.H
@@ -55,6 +55,8 @@ class Engine : public Mutex
     void timebase ( jack_transport_state_t state, jack_nframes_t nframes, jack_position_t *pos, int new_pos );
     static void freewheel ( int yes, void *arg );
     void freewheel ( bool yes );
+    static int buffer_size ( nframes_t nframes, void *arg );
+    int buffer_size ( nframes_t nframes );
 
     Engine ( const Engine &rhs );
     Engine & operator = ( const Engine &rhs );
diff --git a/Timeline/Playback_DS.C b/Timeline/Playback_DS.C
index 6f22a56..863b998 100644
--- a/Timeline/Playback_DS.C
+++ b/Timeline/Playback_DS.C
@@ -54,7 +54,7 @@ Playback_DS::seek ( nframes_t frame )
 
     _pending_seek = frame;
 
-    flush( true );
+    flush();
 }
 
 /* THREAD: IO */
@@ -93,7 +93,6 @@ Playback_DS::read_block ( sample_t *buf, nframes_t nframes )
 void
 Playback_DS::disk_thread ( void )
 {
-
     DMESSAGE( "playback thread running" );
 
     /* buffer to hold the interleaved data returned by the track reader */
diff --git a/Timeline/Playback_DS.H b/Timeline/Playback_DS.H
index 1bfe8f6..bced5f3 100644
--- a/Timeline/Playback_DS.H
+++ b/Timeline/Playback_DS.H
@@ -25,6 +25,8 @@ class Playback_DS : public Disk_Stream
     void read_block ( sample_t *buf, nframes_t nframes );
     void disk_thread ( void );
 
+    void flush ( void ) { base_flush( true ); }
+
 public:
 
     Playback_DS ( Track *th, float frame_rate, nframes_t nframes, int channels ) :
diff --git a/Timeline/Record_DS.C b/Timeline/Record_DS.C
index b4ff69d..f65dd3e 100644
--- a/Timeline/Record_DS.C
+++ b/Timeline/Record_DS.C
@@ -199,7 +199,7 @@ Record_DS::start ( nframes_t frame )
     }
 
     /* FIXME: safe to do this here? */
-    flush( false );
+    flush();
 
     _frame = frame;
 
diff --git a/Timeline/Record_DS.H b/Timeline/Record_DS.H
index be6facb..fa7d4dc 100644
--- a/Timeline/Record_DS.H
+++ b/Timeline/Record_DS.H
@@ -43,6 +43,8 @@ class Record_DS : public Disk_Stream
     void write_block ( sample_t *buf, nframes_t nframes );
     void disk_thread ( void );
 
+    void flush ( void ) { base_flush( false ); }
+
 public:
 
     Record_DS ( Track *th, float frame_rate, nframes_t nframes, int channels ) :
diff --git a/Timeline/Timeline.C b/Timeline/Timeline.C
index ba0479e..99ac3a2 100644
--- a/Timeline/Timeline.C
+++ b/Timeline/Timeline.C
@@ -1233,6 +1233,18 @@ Timeline::seek ( nframes_t frame )
     }
 }
 
+/* THREAD: RT (non-RT) */
+void
+Timeline::resize_buffers ( nframes_t nframes )
+{
+    for ( int i = tracks->children(); i-- ; )
+    {
+        Track *t = (Track*)tracks->child( i );
+
+        t->resize_buffers( nframes );
+    }
+}
+
 /* THREAD: RT */
 int
 Timeline::seek_pending ( void )
diff --git a/Timeline/Timeline.H b/Timeline/Timeline.H
index 8ca8349..8453285 100644
--- a/Timeline/Timeline.H
+++ b/Timeline/Timeline.H
@@ -210,6 +210,7 @@ private:
     char * get_unique_track_name ( const char *name );
 
     /* Engine */
+    void resize_buffers ( nframes_t nframes );
     nframes_t process ( nframes_t nframes );
     void seek ( nframes_t frame );
     int seek_pending ( void );
diff --git a/Timeline/Track.C b/Timeline/Track.C
index a6237bd..a7ed8ff 100644
--- a/Timeline/Track.C
+++ b/Timeline/Track.C
@@ -745,7 +745,15 @@ Track::seek ( nframes_t frame )
         return playback_ds->seek( frame );
 }
 
-
+/* THREAD: RT (non-RT) */
+void
+Track::resize_buffers ( nframes_t nframes )
+{
+    if ( record_ds )
+        record_ds->resize_buffers( nframes );
+    if ( playback_ds )
+        playback_ds->resize_buffers( nframes );
+}
 
 /* FIXME: what about theading issues with this region/audiofile being
    accessible from the UI thread? Need locking? */
diff --git a/Timeline/Track.H b/Timeline/Track.H
index 7099595..8be2498 100644
--- a/Timeline/Track.H
+++ b/Timeline/Track.H
@@ -265,6 +265,7 @@ public:
     const Audio_Region *capture ( void ) const { return _capture; }
 
     /* Engine */
+    void resize_buffers ( nframes_t nframes );
     nframes_t process ( nframes_t nframes );
     void seek ( nframes_t frame );
     void record ( nframes_t nframes );