--- a/dom/media/webaudio/PannerNode.cpp
+++ b/dom/media/webaudio/PannerNode.cpp
@@ -562,21 +562,26 @@ PannerNodeEngine::EqualPowerPanningFunct
       orientationY[0] = mOrientationY.GetValueAtTime(tick);
     }
     if (!mOrientationZ.HasSimpleValue()) {
       mOrientationZ.GetValuesAtTime(tick, orientationZ, WEBAUDIO_BLOCK_SIZE);
     } else {
       orientationZ[0] = mOrientationZ.GetValueAtTime(tick);
     }
 
-    float computedGain[2*WEBAUDIO_BLOCK_SIZE + 4];
+    float buffer[3*WEBAUDIO_BLOCK_SIZE + 4];
     bool onLeft[WEBAUDIO_BLOCK_SIZE];
 
-    float* alignedComputedGain = ALIGNED16(computedGain);
-    ASSERT_ALIGNED16(alignedComputedGain);
+    float* alignedPanningL = ALIGNED16(buffer);
+    float* alignedPanningR = alignedPanningL + WEBAUDIO_BLOCK_SIZE;
+    float* alignedGain = alignedPanningR + WEBAUDIO_BLOCK_SIZE;
+    ASSERT_ALIGNED16(alignedPanningL);
+    ASSERT_ALIGNED16(alignedPanningR);
+    ASSERT_ALIGNED16(alignedGain);
+
     for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
       ThreeDPoint position(mPositionX.HasSimpleValue() ? positionX[0] : positionX[counter],
                            mPositionY.HasSimpleValue() ? positionY[0] : positionY[counter],
                            mPositionZ.HasSimpleValue() ? positionZ[0] : positionZ[counter]);
       ThreeDPoint orientation(mOrientationX.HasSimpleValue() ? orientationX[0] : orientationX[counter],
                               mOrientationY.HasSimpleValue() ? orientationY[0] : orientationY[counter],
                               mOrientationZ.HasSimpleValue() ? orientationZ[0] : orientationZ[counter]);
       if (!orientation.IsZero()) {
@@ -606,27 +611,34 @@ PannerNodeEngine::EqualPowerPanningFunct
         } else {
           normalizedAzimuth = azimuth / 90.f;
         }
       }
 
       distanceGain = ComputeDistanceGain(position);
 
       // Actually compute the left and right gain.
-      float gainL = cos(0.5 * M_PI * normalizedAzimuth) * aInput.mVolume * distanceGain * coneGain;
-      float gainR = sin(0.5 * M_PI * normalizedAzimuth) * aInput.mVolume * distanceGain * coneGain;
+      float gainL = cos(0.5 * M_PI * normalizedAzimuth);
+      float gainR = sin(0.5 * M_PI * normalizedAzimuth);
+
 
-      alignedComputedGain[counter] = gainL;
-      alignedComputedGain[WEBAUDIO_BLOCK_SIZE + counter] = gainR;
+      alignedPanningL[counter] = gainL;
+      alignedPanningR[counter] = gainR;
+      alignedGain[counter] = aInput.mVolume * distanceGain * coneGain;
       onLeft[counter] = azimuth <= 0;
     }
 
-    // Apply the gain to the output buffer
-    ApplyStereoPanning(aInput, aOutput, alignedComputedGain, &alignedComputedGain[WEBAUDIO_BLOCK_SIZE], onLeft);
+    // Apply the panning to the output buffer
+    ApplyStereoPanning(aInput, aOutput, alignedPanningL, alignedPanningR, onLeft);
 
+    // Apply the input volume, cone and distance gain to the output buffer.
+    float* outputL = aOutput->ChannelFloatsForWrite(0);
+    float* outputR = aOutput->ChannelFloatsForWrite(1);
+    AudioBlockInPlaceScale(outputL, alignedGain);
+    AudioBlockInPlaceScale(outputR, alignedGain);
   }
 }
 
 // This algorithm is specified in the webaudio spec.
 void
 PannerNodeEngine::ComputeAzimuthAndElevation(const ThreeDPoint& position, float& aAzimuth, float& aElevation)
 {
   ThreeDPoint sourceListener = position - mListenerPosition;