target manages instrument setting

src/blocks/scratch3_sound.js

@@ -93,7 +93,8 @@ Scratch3SoundBlocks.prototype.setInstrument = function (args, util) {
     var instNum = Cast.toNumber(args.INSTRUMENT);
     instNum -= 1; // instruments are one-indexed
     instNum = MathUtil.wrapClamp(instNum, 0, this.runtime.audioEngine.numInstruments);
-    return util.target.audioPlayer.setInstrument(instNum);
+    util.target.setInstrument(instNum);
+    return this.runtime.audioEngine.instrumentPlayer.loadInstrument(instNum);
 };
 
 Scratch3SoundBlocks.prototype.setEffect = function (args, util) {

src/sprites/rendered-target.js

@@ -484,6 +484,10 @@ RenderedTarget.prototype.updateAllDrawableProperties = function () {
 RenderedTarget.prototype.playSound = function (index) {
     return this.audioPlayer.playSound(this.sprite.sounds[index].md5);
 };
+
+RenderedTarget.prototype.setInstrument = function (num) {
+    this.currentInstrument = num;
+};
 /**
  * Return the human-readable name for this rendered target, e.g., the sprite's name.
  * @override