fix Effect bugs

src/AudioPlayer.js

@@ -142,6 +142,7 @@ class AudioPlayer {
      * @param {object} target - target whose node to should be connected
      */
     connect (target) {
+        this.outputNode.disconnect();
         this.outputNode.connect(target.getInputNode());
     }
 

src/effects/Effect.js

@@ -38,7 +38,7 @@ class Effect {
      * @return {boolean} is the effect affecting the graph?
      */
     get _isPatch () {
-        return this.initialized;
+        return this.initialized && this.value !== this.DEFAULT_VALUE;
     }
 
     /**
@@ -46,7 +46,7 @@ class Effect {
      * @return {AudioNode} - audio node that is the input for this effect
      */
     getInputNode () {
-        if (this.initialized) {
+        if (this._isPatch) {
             return this.inputNode;
         }
         return this.target.getInputNode();
@@ -117,6 +117,10 @@ class Effect {
             return;
         }
 
+        if (this.outputNode !== null) {
+            this.outputNode.disconnect();
+        }
+
         let nextTarget = target;
         if (this._isPatch) {
             nextTarget = this;

src/effects/PanEffect.js

@@ -20,14 +20,6 @@ class PanEffect extends Effect {
         this.channelMerger = null;
     }
 
-    /**
-     * Should the effect be connected to the audio graph?
-     * @return {boolean} is the effect affecting the graph?
-     */
-    get _isPatch () {
-        return this.initialized && this.value !== 0;
-    }
-
     /**
      * Initialize the Effect.
      * Effects start out uninitialized. Then initialize when they are first set