--- a/build/automation.py.in
+++ b/build/automation.py.in
@@ -450,19 +450,16 @@ user_pref("extensions.getAddons.getWithP
 user_pref("extensions.getAddons.search.browseURL", "http://%(server)s/extensions-dummy/repositoryBrowseURL");
 user_pref("extensions.getAddons.search.url", "http://%(server)s/extensions-dummy/repositorySearchURL");
 
 // Make enablePrivilege continue to work for test code. :-(
 user_pref("security.turn_off_all_security_so_that_viruses_can_take_over_this_computer", true);
 
 // Get network events.
 user_pref("network.activity.blipIntervalMilliseconds", 250);
-
-// Shut up the media volume level.
-user_pref("media.volume_scale", "0.05");
 """ % { "server" : self.webServer + ":" + str(self.httpPort) }
     prefs.append(part)
 
     if useServerLocations:
       # We need to proxy every server but the primary one.
       origins = ["'%s://%s:%s'" % (l.scheme, l.host, l.port)
                 for l in filter(lambda l: "primary" not in l.options, locations)]
       origins = ", ".join(origins)

--- a/layout/tools/reftest/bootstrap.js
+++ b/layout/tools/reftest/bootstrap.js
@@ -28,18 +28,16 @@ function setDefaultPrefs() {
     branch.setBoolPref("extensions.update.enabled", false);
     branch.setBoolPref("extensions.getAddons.cache.enabled", false);
     // Disable blocklist updates so we don't have them reported as leaks
     branch.setBoolPref("extensions.blocklist.enabled", false);
     // Make url-classifier updates so rare that they won't affect tests
     branch.setIntPref("urlclassifier.updateinterval", 172800);
     // Disable high-quality downscaling, since it makes reftests more difficult.
     branch.setBoolPref("image.high_quality_downscaling.enabled", false);
-    // Shut up the media prefs when running tests.
-    branch.setIntPref("media.volume_scale", "0.05");
 }
 
 var windowListener = {
     onOpenWindow: function(aWindow) {
         let domWindow = aWindow.QueryInterface(Components.interfaces.nsIInterfaceRequestor).getInterface(Components.interfaces.nsIDOMWindowInternal || Components.interfaces.nsIDOMWindow);
         domWindow.addEventListener("load", function() {
             domWindow.removeEventListener("load", arguments.callee, false);