Only add gain node when normalization enabled

src/plugins/htmlAudioPlayer/plugin.js

@@ -121,6 +121,13 @@ class HtmlAudioPlayer {
                     normalizationGain =
                         options.mediaSource.albumNormalizationGain
                         ?? options.item.NormalizationGain;
+                } else {
+                    console.debug('normalization disabled')
+                    return;
+                }
+
+                if (!self.gainNode) {
+                    addGainElement(elem);
                 }
 
                 if (normalizationGain) {
@@ -276,7 +283,7 @@ class HtmlAudioPlayer {
 
             self._mediaElement = elem;
 
-            addGainElement(elem);
+            // addGainElement(elem);
 
             return elem;
         }
@@ -317,7 +324,7 @@ class HtmlAudioPlayer {
         function onVolumeChange() {
             if (!self._isFadingOut) {
                 htmlMediaHelper.saveVolume(this.volume);
-                if (browser.safari) {
+                if (browser.safari && self.gainNode) {
                     self.gainNode.gain.value = this.volume * self.normalizationGain;
                 }
                 Events.trigger(self, 'volumechange');