diff --git a/src/virtual-machine.js b/src/virtual-machine.js
index 4e0a2bb11..e2b18f2a3 100644
--- a/src/virtual-machine.js
+++ b/src/virtual-machine.js
@@ -414,12 +414,34 @@ class VirtualMachine extends EventEmitter {
      * Update a sound buffer.
      * @param {int} soundIndex - the index of the sound to be updated.
      * @param {AudioBuffer} newBuffer - new audio buffer for the audio engine.
+     * @param {ArrayBuffer} soundEncoding - the new (wav) encoded sound to be stored
      */
-    updateSoundBuffer (soundIndex, newBuffer) {
-        const id = this.editingTarget.sprite.sounds[soundIndex].soundId;
+    updateSoundBuffer (soundIndex, newBuffer, soundEncoding) {
+        const sound = this.editingTarget.sprite.sounds[soundIndex];
+        const id = sound ? sound.soundId : null;
         if (id && this.runtime && this.runtime.audioEngine) {
             this.runtime.audioEngine.updateSoundBuffer(id, newBuffer);
         }
+        // Update sound in runtime
+        if (soundEncoding) {
+            // Now that we updated the sound, the format should also be updated
+            // so that the sound can eventually be decoded the right way.
+            // Sounds that were formerly 'adpcm', but were updated in sound editor
+            // will not get decoded by the audio engine correctly unless the format
+            // is updated as below.
+            sound.format = '';
+            const storage = this.runtime.storage;
+            sound.assetId = storage.builtinHelper.cache(
+                storage.AssetType.Sound,
+                storage.DataFormat.WAV,
+                soundEncoding
+            );
+            sound.md5 = `${sound.assetId}.${sound.dataFormat}`;
+        }
+        // If soundEncoding is null, it's because gui had a problem
+        // encoding the updated sound. We don't want to store anything in this
+        // case, and gui should have logged an error.
+
         this.emitTargetsUpdate();
     }