diff --git a/src/DrumPlayer.js b/src/DrumPlayer.js
index b020542..3d1aaf4 100644
--- a/src/DrumPlayer.js
+++ b/src/DrumPlayer.js
@@ -38,7 +38,7 @@ class DrumPlayer {
 
             // download and decode the drum sounds
             // @todo: use scratch-storage to manage these sound files
-            const url = baseUrl + fileNames[i] + '_22k.wav';
+            const url = `${baseUrl}${fileNames[i]}_22k.wav`;
             const request = new XMLHttpRequest();
             request.open('GET', url, true);
             request.responseType = 'arraybuffer';
diff --git a/src/InstrumentPlayer.js b/src/InstrumentPlayer.js
index 627e910..bb3484d 100644
--- a/src/InstrumentPlayer.js
+++ b/src/InstrumentPlayer.js
@@ -9,7 +9,7 @@ class InstrumentPlayer {
      * play note or set instrument block runs, causing a delay of a few seconds.
      * Using this library we don't have a way to set the volume, sustain the note beyond the sample
      * duration, or run it through the sprite-specific audio effects.
-     * @param {AudioNode} outputNode - a webAudio node that the instrument will send its output to
+     * @param {AudioContext} context - a webAudio context
      * @constructor
      */
     constructor (context) {
diff --git a/src/effects/PitchEffect.js b/src/effects/PitchEffect.js
index 7cebc44..3de5c5b 100644
--- a/src/effects/PitchEffect.js
+++ b/src/effects/PitchEffect.js
@@ -59,7 +59,7 @@ class PitchEffect {
     * @returns {number} a frequency ratio
     */
     intervalToFrequencyRatio (interval) {
-        return Math.pow(2, (interval/12));
+        return Math.pow(2, (interval / 12));
     }
 
     /**
diff --git a/src/index.js b/src/index.js
index ea53ea7..ff638ba 100644
--- a/src/index.js
+++ b/src/index.js
@@ -149,7 +149,7 @@ class AudioPlayer {
  */
 class AudioEngine {
     constructor () {
-        var AudioContext = window.AudioContext || window.webkitAudioContext;
+        const AudioContext = window.AudioContext || window.webkitAudioContext;
         this.context = new AudioContext();
 
         this.input = this.context.createGain();
@@ -200,7 +200,7 @@ class AudioEngine {
         let loaderPromise = null;
 
         // Make a copy of the buffer because decoding detaches the original buffer
-        var bufferCopy = sound.data.buffer.slice(0);
+        const bufferCopy = sound.data.buffer.slice(0);
 
         switch (sound.format) {
         case '':
@@ -296,13 +296,14 @@ class AudioEngine {
         // the microphone has not been set up, try to connect to it
         if (!this.mic && !this.connectingToMic) {
             this.connectingToMic = true; // prevent multiple connection attempts
-            navigator.mediaDevices.getUserMedia({audio : true}).then(stream => {
+            navigator.mediaDevices.getUserMedia({audio: true}).then(stream => {
                 this.mic = this.context.createMediaStreamSource(stream);
                 this.analyser = this.context.createAnalyser();
                 this.mic.connect(this.analyser);
                 this.micDataArray = new Float32Array(this.analyser.fftSize);
-            }).catch(err => {
-                log.warn(err)
+            })
+            .catch(err => {
+                log.warn(err);
             });
         }