diff --git a/examples/kong.sf2 b/examples/harp.sf2
similarity index 100%
rename from examples/kong.sf2
rename to examples/harp.sf2
diff --git a/examples/player.ce b/examples/player.ce
index f8a036c..ae41323 100644
--- a/examples/player.ce
+++ b/examples/player.ce
@@ -38,7 +38,7 @@ if (!midi_blob) {
 }
 
 var song = midi.parse(midi_blob)
-log.console("MIDI loaded: " + text(song.note_count) + " notes, " + text((song.duration_ms / 1000).toFixed(1)) + " seconds")
+log.console("MIDI loaded: " + text(song.note_count) + " notes, " + text((song.duration_ms / 1000)) + " seconds")
 
 var player = midi.Player(soundfont, song)
 
@@ -94,8 +94,8 @@ function progress() {
   
   var pos = player.position_ms() / 1000
   var dur = player.duration_ms() / 1000
-  var pct = (pos / dur * 100).toFixed(0)
-  log.console(`\r${pos.toFixed(1)}s / ${dur.toFixed(1)}s (${pct}%) - ${soundfont.active_voices()} voices  `, false)
+  var pct = text(pos / dur * 100)
+  log.console(`\r${text(pos)}s / ${dur}s (${pct}%) - ${soundfont.active_voices()} voices  `, false)
   $delay(progress, 0.1)
 }
 
diff --git a/midi.c b/internal/midi.c
similarity index 97%
rename from midi.c
rename to internal/midi.c
index 3dd86fe..ef50026 100644
--- a/midi.c
+++ b/internal/midi.c
@@ -22,7 +22,11 @@ JSC_CCALL(soundfont_load,
   // Set default output: stereo interleaved, 44100Hz
   tsf_set_output(sf, TSF_STEREO_INTERLEAVED, 44100, 0.0f);
   tsf_set_max_voices(sf, 256);
-  
+
+  // Initialize all 16 MIDI channels with default preset 0
+  for (int i = 0; i < 16; i++)
+    tsf_channel_set_presetnumber(sf, i, 0, i == 9);
+
   return JS_NewInt64(js, (int64_t)(uintptr_t)sf);
 )
 
@@ -56,14 +60,14 @@ JSC_CCALL(soundfont_note_on,
   int64_t ptr;
   JS_ToInt64(js, &ptr, argv[0]);
   tsf *sf = (tsf*)(uintptr_t)ptr;
-  if (!sf) return JS_NULL;
-  
+
   int channel, key;
   double vel;
   JS_ToInt32(js, &channel, argv[1]);
   JS_ToInt32(js, &key, argv[2]);
   JS_ToFloat64(js, &vel, argv[3]);
-  
+
+  if (!sf) return JS_NULL;
   tsf_channel_note_on(sf, channel, key, (float)vel);
   return JS_NULL;
 )
@@ -156,15 +160,15 @@ JSC_CCALL(soundfont_render,
   if (argc > 1) JS_ToInt32(js, &frames, argv[1]);
   
   size_t size = frames * 2 * sizeof(float); // stereo
-  float *buffer = js_malloc(js, size);
+  float *buffer = malloc(size);
   if (!buffer) return JS_NULL;
-  
+
   memset(buffer, 0, size);
   tsf_render_float(sf, buffer, frames, 0);
 
   JSValue blob = js_new_blob_stoned_copy(js, buffer, size);
-  js_free(js, buffer);
-  
+  free(buffer);
+
   return blob;
 )
 
@@ -237,10 +241,11 @@ JSC_CCALL(midi_parse,
 
   // Build events array
   JS_ROOT(events, JS_NewArray(js));
+  JS_ROOT(evt, JS_NULL);
   int idx = 0;
 
   for (tml_message *msg = midi; msg; msg = msg->next) {
-    JS_ROOT(evt, JS_NewObject(js));
+    evt.val = JS_NewObject(js);
     JS_SetPropertyStr(js, evt.val, "time", JS_NewInt32(js, msg->time));
     JS_SetPropertyStr(js, evt.val, "channel", JS_NewInt32(js, msg->channel));
 
diff --git a/midi.cm b/midi.cm
index 7c5744b..5889b87 100644
--- a/midi.cm
+++ b/midi.cm
@@ -20,7 +20,7 @@
  *   player.render(frames) - render audio samples
  */
 
-var native = this
+var native = use('internal/midi')
 
 var SAMPLE_RATE = 44100
 
@@ -87,7 +87,8 @@ function Soundfont(blob) {
 
 // Parse MIDI file
 function parse(blob) {
-  return native.parse(blob)
+  var val = native.parse(blob)
+  return val
 }
 
 // MIDI Player - plays a parsed MIDI through a soundfont
@@ -101,7 +102,7 @@ function Player(soundfont, song) {
   self.soundfont = soundfont
   self.song = song
   self.loop = false
-  
+
   // Process events up to current time
   function process_events(time_ms) {
     var evt = null