diff --git a/cwMIDISynth/cwMIDISynth.js b/cwMIDISynth/cwMIDISynth.js
index 67135a0..fb4228c 100644
--- a/cwMIDISynth/cwMIDISynth.js
+++ b/cwMIDISynth/cwMIDISynth.js
@@ -109,7 +109,9 @@ WebMIDI.cwMIDISynth = (function()
 			return new CWMIDISynth();
 		}
 
-		/** WebMIDIAPI §10 -- MIDIPort interface **/
+		// WebMIDIAPI §4.6 -- MIDIPort interface
+		// See https://github.com/notator/WebMIDISynthHost/issues/23
+		// and https://github.com/notator/WebMIDISynthHost/issues/24
 		Object.defineProperty(this, "id", { value: "cwMIDISynth", writable: false });
 		Object.defineProperty(this, "manufacturer", { value: "chris wilson", writable: false });
 		Object.defineProperty(this, "name", { value: "MIDI synth (Chris Wilson)", writable: false });
@@ -143,6 +145,20 @@ WebMIDI.cwMIDISynth = (function()
 		console.log("cwMIDISynth initialised.");
 	};
 
+	// WebMIDIAPI §4.6 -- MIDIPort interface
+	// See https://github.com/notator/WebMIDISynthHost/issues/24
+	CWMIDISynth.prototype.open = function()
+	{
+		console.log("cwMIDISynth opened.");
+	};
+
+	// WebMIDIAPI §4.6 -- MIDIPort interface
+	// See https://github.com/notator/WebMIDISynthHost/issues/24
+	CWMIDISynth.prototype.close = function()
+	{
+		console.log("cwMIDISynth closed.");
+	};
+
 	// WebMIDIAPI MIDIOutput send()
 	// This synth does not support timestamps
 	CWMIDISynth.prototype.send = function(message, ignoredTimestamp)
diff --git a/sf2Synth1/sf2Synth1.js b/sf2Synth1/sf2Synth1.js
index 2a6dfee..37d4a9f 100644
--- a/sf2Synth1/sf2Synth1.js
+++ b/sf2Synth1/sf2Synth1.js
@@ -108,7 +108,9 @@ WebMIDI.sf2Synth1 = (function(window)
 			return new Sf2Synth1();
 		}
 
-		/** WebMIDIAPI §10 -- MIDIPort interface **/
+		// WebMIDIAPI §4.6 -- MIDIPort interface
+		// See https://github.com/notator/WebMIDISynthHost/issues/23
+		// and https://github.com/notator/WebMIDISynthHost/issues/24
 		Object.defineProperty(this, "id", { value: "Sf2Synth01", writable: false });
 		Object.defineProperty(this, "manufacturer", { value: "gree & ji", writable: false });
 		Object.defineProperty(this, "name", { value: "Sf2Synth1 (gree & ji)", writable: false });
@@ -169,6 +171,20 @@ WebMIDI.sf2Synth1 = (function(window)
     };
 	// end var
 
+	// WebMIDIAPI §4.6 -- MIDIPort interface
+	// See https://github.com/notator/WebMIDISynthHost/issues/24
+	Sf2Synth1.prototype.open = function()
+	{
+		console.log("sf2Synth1 opened.");
+	};
+
+	// WebMIDIAPI §4.6 -- MIDIPort interface
+	// See https://github.com/notator/WebMIDISynthHost/issues/24
+	Sf2Synth1.prototype.close = function()
+	{
+		console.log("sf2Synth1 closed.");
+	};
+
 	// WebMIDIAPI MIDIOutput send()
 	// This synth does not yet support timestamps (05.11.2015)
 	Sf2Synth1.prototype.send = function(message, ignoredTimestamp)