--- a/webaudio/specification.html	Tue Mar 26 14:06:14 2013 -0700
+++ b/webaudio/specification.html	Tue Mar 26 16:41:45 2013 -0700
@@ -2795,7 +2795,7 @@
 
 interface <dfn id="dfn-ConvolverNode">ConvolverNode</dfn> : AudioNode {
 
-    attribute AudioBuffer buffer;
+    attribute AudioBuffer? buffer;
     attribute boolean normalize;
 
 };
@@ -2810,7 +2810,8 @@
   <dt id="dfn-buffer_ConvolverNode"><code>buffer</code></dt>
     <dd><p>A mono, stereo, or 4-channel <code>AudioBuffer</code> containing the (possibly multi-channel) impulse response
       used by the ConvolverNode.  At the time when this attribute is set, the <em>buffer</em> and the state of the <em>normalize</em>
-      attribute will be used to configure the ConvolverNode with this impulse response having the given normalization.</p>
+      attribute will be used to configure the ConvolverNode with this impulse response having the given normalization.
+      The initial value of this attribute is null.</p>
     </dd>
 </dl>
 <dl>