diff --git a/src/InstrumentPlayer.js b/src/InstrumentPlayer.js
index 81dbacb..718fad5 100644
--- a/src/InstrumentPlayer.js
+++ b/src/InstrumentPlayer.js
@@ -34,12 +34,17 @@ function InstrumentPlayer (outputNode) {
  * @param  {number} note - a MIDI note number
  * @param  {number} sec - a duration in seconds
  * @param  {number} instrumentNum - an instrument number (0-indexed)
+ * @param  {number} vol - a volume level (0-100%)
  */
-InstrumentPlayer.prototype.playNoteForSecWithInst = function (note, sec, instrumentNum) {
+InstrumentPlayer.prototype.playNoteForSecWithInstAndVol = function (note, sec, instrumentNum, vol) {
+    var gain = vol / 100;
     this.loadInstrument(instrumentNum)
         .then(() => {
             this.instruments[instrumentNum].play(
-                note, Tone.context.currentTime, {duration : sec}
+                note, Tone.context.currentTime, {
+                    duration : sec,
+                    gain : gain
+                }
             );
         });
 };
diff --git a/src/index.js b/src/index.js
index bb6fa7c..047d83b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -91,15 +91,16 @@ AudioEngine.prototype.loadSounds = function (sounds) {
 };
 
 /**
- * Play a note for a duration on an instrument
+ * Play a note for a duration on an instrument with a volume
  * @param  {number} note - a MIDI note number
  * @param  {number} beats - a duration in beats
  * @param  {number} inst - an instrument number (0-indexed)
+ * @param  {number} vol - a volume level (0-100%)
  * @return {Promise} a Promise that resolves after the duration has elapsed
  */
-AudioEngine.prototype.playNoteForBeatsWithInst = function (note, beats, inst) {
+AudioEngine.prototype.playNoteForBeatsWithInstAndVol = function (note, beats, inst, vol) {
     var sec = this.beatsToSec(beats);
-    this.instrumentPlayer.playNoteForSecWithInst(note, sec, inst);
+    this.instrumentPlayer.playNoteForSecWithInstAndVol(note, sec, inst, vol);
     return this.waitForBeats(beats);
 };