Add note about volume calibration. Fixes #225

html/index.html

@@ -1209,9 +1209,11 @@ <h3>Something else weird is going on</h3>
 
   <p>
 
-  Now we need to calibrate your volume. You probably want to turn your
-  speaker volume back down.  Pick something you're comfortable
-  singing, start singing, and then click <button
+  Now we need to calibrate your volume. This will only apply to music
+  making; the video call portion automatically adjusts to your current
+  volume. You probably want to turn your speaker volume back down.
+  Pick something you're comfortable singing, start singing, and then
+  click <button
   id=startVolumeCalibration>I've begun singing</button>.
 
   <p>