diff --git a/README.md b/README.md
index 3830a91d..786ed8e2 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# Recorder.js
+# Recorder.js
 
 ## A plugin for recording/exporting the output of Web Audio API nodes
 
@@ -18,6 +18,8 @@ Creates a recorder instance.
 - **bufferLen** - The length of the buffer that the internal JavaScriptNode uses to capture the audio. Can be tweaked if experiencing performance issues. Defaults to 4096.
 - **callback** - A default callback to be used with `exportWAV`.
 - **type** - The type of the Blob generated by `exportWAV`. Defaults to 'audio/wav'.
+- **sampleRate** - The sample rate.
+- **numChannels** - Determines whether audio is mono (1) or stereo (2). Defaults to 2.
 
 ---------
 #### Instance Methods
diff --git a/dist/recorder.js b/dist/recorder.js
index 42a6ad0f..5b1b8215 100644
--- a/dist/recorder.js
+++ b/dist/recorder.js
@@ -259,7 +259,7 @@
                             /* sample rate */
                             view.setUint32(24, sampleRate, true);
                             /* byte rate (sample rate * block align) */
-                            view.setUint32(28, sampleRate * 4, true);
+                            view.setUint32(28, sampleRate * numChannels * 2, true);
                             /* block align (channel count * bytes per sample) */
                             view.setUint16(32, numChannels * 2, true);
                             /* bits per sample */
diff --git a/examples/example_simple_exportwav.html b/examples/example_simple_exportwav.html
index a28bda64..bd82c7f5 100644
--- a/examples/example_simple_exportwav.html
+++ b/examples/example_simple_exportwav.html
@@ -86,7 +86,7 @@ <h2>Log</h2>
     try {
       // webkit shim
       window.AudioContext = window.AudioContext || window.webkitAudioContext;
-      navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia;
+      navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
       window.URL = window.URL || window.webkitURL;
       
       audio_context = new AudioContext;
diff --git a/lib/recorder.js b/lib/recorder.js
index d19cb210..dfc1ea2e 100644
--- a/lib/recorder.js
+++ b/lib/recorder.js
@@ -210,7 +210,7 @@ var Recorder = exports.Recorder = (function () {
                 /* sample rate */
                 view.setUint32(24, sampleRate, true);
                 /* byte rate (sample rate * block align) */
-                view.setUint32(28, sampleRate * 4, true);
+                view.setUint32(28, sampleRate * numChannels * 2, true);
                 /* block align (channel count * bytes per sample) */
                 view.setUint16(32, numChannels * 2, true);
                 /* bits per sample */
diff --git a/src/recorder.js b/src/recorder.js
index 68ca8ca6..5004c9c5 100644
--- a/src/recorder.js
+++ b/src/recorder.js
@@ -173,7 +173,7 @@ export class Recorder {
                 /* sample rate */
                 view.setUint32(24, sampleRate, true);
                 /* byte rate (sample rate * block align) */
-                view.setUint32(28, sampleRate * 4, true);
+                view.setUint32(28, sampleRate * numChannels * 2, true);
                 /* block align (channel count * bytes per sample) */
                 view.setUint16(32, numChannels * 2, true);
                 /* bits per sample */