--- a/dom/media/tests/mochitest/head.js
+++ b/dom/media/tests/mochitest/head.js
@@ -415,17 +415,18 @@ function setupEnvironment() {
       ['media.peerconnection.remoteTrackId.enabled', true],
       ['media.peerconnection.rtpsourcesapi.enabled', true],
       ['media.navigator.permission.disabled', true],
       // If either fake audio or video is desired we enable fake streams.
       // If loopback devices are set they will be chosen instead of fakes in gecko.
       ['media.navigator.streams.fake', WANT_FAKE_AUDIO || WANT_FAKE_VIDEO],
       ['media.getusermedia.screensharing.enabled', true],
       ['media.getusermedia.audiocapture.enabled', true],
-      ['media.recorder.audio_node.enabled', true]
+      ['media.recorder.audio_node.enabled', true],
+      ['media.webaudio.audiocontextoptions-samplerate.enabled', true]
     ]
   };
 
   if (!WANT_FAKE_AUDIO) {
     defaultMochitestPrefs.set.push(
       ["media.volume_scale", "1"],
     );
   }

--- a/dom/media/webaudio/AudioContext.cpp
+++ b/dom/media/webaudio/AudioContext.cpp
@@ -6,16 +6,17 @@
 
 #include "AudioContext.h"
 
 #include "blink/PeriodicWave.h"
 
 #include "mozilla/ErrorResult.h"
 #include "mozilla/OwningNonNull.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/Preferences.h"
 
 #include "mozilla/dom/AnalyserNode.h"
 #include "mozilla/dom/AnalyserNodeBinding.h"
 #include "mozilla/dom/AudioBufferSourceNodeBinding.h"
 #include "mozilla/dom/AudioContextBinding.h"
 #include "mozilla/dom/BaseAudioContextBinding.h"
 #include "mozilla/dom/BiquadFilterNodeBinding.h"
 #include "mozilla/dom/ChannelMergerNodeBinding.h"
@@ -201,28 +202,32 @@ AudioContext::Constructor(const GlobalOb
                           ErrorResult& aRv)
 {
   nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(aGlobal.GetAsSupports());
   if (!window) {
     aRv.Throw(NS_ERROR_FAILURE);
     return nullptr;
   }
 
-  if (aOptions.mSampleRate > 0 &&
-      (aOptions.mSampleRate - WebAudioUtils::MinSampleRate < 0.0 ||
-      WebAudioUtils::MaxSampleRate - aOptions.mSampleRate < 0.0)) {
-    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
-    return nullptr;
+  float sampleRate = MediaStreamGraph::REQUEST_DEFAULT_SAMPLE_RATE;
+  if (Preferences::GetBool("media.webaudio.audiocontextoptions-samplerate.enabled")) {
+    if (aOptions.mSampleRate > 0 &&
+        (aOptions.mSampleRate - WebAudioUtils::MinSampleRate < 0.0 ||
+        WebAudioUtils::MaxSampleRate - aOptions.mSampleRate < 0.0)) {
+      aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+      return nullptr;
+    }
+    sampleRate = aOptions.mSampleRate;
   }
 
   uint32_t maxChannelCount = std::min<uint32_t>(WebAudioUtils::MaxChannelCount,
       CubebUtils::MaxNumberOfChannels());
   RefPtr<AudioContext> object =
     new AudioContext(window, false, maxChannelCount,
-                     0, aOptions.mSampleRate);
+                     0, sampleRate);
   aRv = object->Init();
   if (NS_WARN_IF(aRv.Failed())) {
      return nullptr;
   }
 
   RegisterWeakMemoryReporter(object);
 
   return object.forget();

--- a/dom/media/webaudio/test/test_audioContextParams_recordNonDefaultSampleRate.html
+++ b/dom/media/webaudio/test/test_audioContextParams_recordNonDefaultSampleRate.html
@@ -35,14 +35,15 @@ function startTest() {
     recorder.start(1000);
     ok(true, 'recorder started');
     is('recording', recorder.state, 'check record state recording');
   } catch (e) {
     ok(false, 'Can t record audio context');
   }
 }
 
+SpecialPowers.setBoolPref("media.webaudio.audiocontextoptions-samplerate.enabled", true);
 startTest();
 SimpleTest.waitForExplicitFinish();
 </script>
 </pre>
 </body>
 </html>

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -661,16 +661,18 @@ pref("media.cubeb.logging_level", "");
 pref("media.cubeb.sandbox", true);
 pref("media.audioipc.pool_size", 2);
 // 64 kB stack per pool thread.
 pref("media.audioipc.stack_size", 65536);
 #else
 pref("media.cubeb.sandbox", false);
 #endif
 
+pref("media.webaudio.audiocontextoptions-samplerate.enabled", true);
+
 // Set to true to force demux/decode warnings to be treated as errors.
 pref("media.playback.warnings-as-errors", false);
 
 // Weather we allow AMD switchable graphics
 pref("layers.amd-switchable-gfx.enabled", true);
 
 // Whether to use async panning and zooming
 pref("layers.async-pan-zoom.enabled", true);