--- a/webaudio/specification.html	Fri May 18 16:33:29 2012 -0700
+++ b/webaudio/specification.html	Fri May 18 17:01:36 2012 -0700
@@ -1630,7 +1630,8 @@
       seconds) the sound should start playing. This time is relative to the
       <b>currentTime</b> attribute of the AudioContext. If 0 is passed in for
       this value or if the value is less than <b>currentTime</b>, then the
-      sound will start playing immediately. </p>
+      sound will start playing immediately.  Either <code>noteOn</code> or <code>noteGrainOn</code> (but not both) may only be called one time
+      and must be called before <code>noteOff</code> is called or an exception will be thrown.</p>
     </dd>
 </dl>
 <dl>
@@ -1644,7 +1645,9 @@
       <p>The <dfn id="dfn-grainOffset">grainOffset</dfn> parameter describes
       the offset in the buffer (in seconds) for the portion to be played.</p>
       <p>The <dfn id="dfn-grainDuration">grainDuration</dfn> parameter
-      describes the duration of the portion (in seconds) to be played. </p>
+      describes the duration of the portion (in seconds) to be played.
+      Either <code>noteOn</code> or <code>noteGrainOn</code> (but not both) may only be called one time
+      and must be called before <code>noteOff</code> is called or an exception will be thrown. </p>
     </dd>
 </dl>
 <dl>
@@ -1654,7 +1657,9 @@
       describes at what time (in seconds) the sound should stop playing. This
       time is relative to the <b>currentTime</b> attribute of the AudioContext.
       If 0 is passed in for this value or if the value is less than
-      <b>currentTime</b>, then the sound will stop playing immediately. </p>
+      <b>currentTime</b>, then the sound will stop playing immediately.
+      <code>noteOff</code> must only be called one time and only after a call to <code>noteOn</code> or <code>noteOff</code>,
+      or an exception will be thrown.</p>
     </dd>
 </dl>
 </div>