diff --git a/src/schule/ngb/zm/events/EventGenerator.java b/src/schule/ngb/zm/events/EventDispatcher.java
similarity index 78%
rename from src/schule/ngb/zm/events/EventGenerator.java
rename to src/schule/ngb/zm/events/EventDispatcher.java
index f8834a0..61722c5 100644
--- a/src/schule/ngb/zm/events/EventGenerator.java
+++ b/src/schule/ngb/zm/events/EventDispatcher.java
@@ -1,22 +1,27 @@
 package schule.ngb.zm.events;
 
+import schule.ngb.zm.util.Validator;
+
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.function.BiConsumer;
 
-public class EventGenerator<E, L extends Listener<E>> {
+public class EventDispatcher<E, L extends Listener<E>> {
 
 	private CopyOnWriteArraySet<L> listeners;
 
 	private ConcurrentMap<String, BiConsumer<E, L>> eventRegistry;
 
-	public EventGenerator() {
+	public EventDispatcher() {
 		listeners = new CopyOnWriteArraySet<>();
 		eventRegistry = new ConcurrentHashMap<>();
 	}
 
 	public void registerEventType( String eventKey, BiConsumer<E, L> dispatcher ) {
+		Validator.requireNotNull(eventKey);
+		Validator.requireNotNull(dispatcher);
+
 		if( !eventRegistered(eventKey) ) {
 			eventRegistry.put(eventKey, dispatcher);
 		}
@@ -39,9 +44,12 @@ public class EventGenerator<E, L extends Listener<E>> {
 	}
 
 	public void dispatchEvent( String eventKey, final E event ) {
+		Validator.requireNotNull(eventKey);
+		Validator.requireNotNull(event);
+
 		if( eventRegistered(eventKey) ) {
 			final BiConsumer<E, L> dispatcher = eventRegistry.get(eventKey);
-			listeners.stream().forEach(( listener ) -> {
+			listeners.forEach(( listener ) -> {
 				dispatcher.accept(event, listener);
 			});
 		}
diff --git a/src/schule/ngb/zm/media/Audio.java b/src/schule/ngb/zm/media/Audio.java
index e2f5137..0292df6 100644
--- a/src/schule/ngb/zm/media/Audio.java
+++ b/src/schule/ngb/zm/media/Audio.java
@@ -5,6 +5,8 @@ package schule.ngb.zm.media;
  */
 public interface Audio {
 
+	String getSource();
+
 	/**
 	 * Prüft, ob das Medium gerade abgespielt wird.
 	 *
diff --git a/src/schule/ngb/zm/media/AudioListener.java b/src/schule/ngb/zm/media/AudioListener.java
new file mode 100644
index 0000000..1600e07
--- /dev/null
+++ b/src/schule/ngb/zm/media/AudioListener.java
@@ -0,0 +1,11 @@
+package schule.ngb.zm.media;
+
+import schule.ngb.zm.events.Listener;
+
+public interface AudioListener extends Listener<Audio> {
+
+	void start( Audio source );
+
+	void stop( Audio source );
+
+}
diff --git a/src/schule/ngb/zm/media/Mixer.java b/src/schule/ngb/zm/media/Mixer.java
index 91b2064..fa68ca8 100644
--- a/src/schule/ngb/zm/media/Mixer.java
+++ b/src/schule/ngb/zm/media/Mixer.java
@@ -41,6 +41,10 @@ public class Mixer implements Audio {
 		this.audios = new ArrayList<>(4);
 	}
 
+	public String getSource() {
+		return "";
+	}
+
 	public void add( Audio pAudio ) {
 		add(pAudio, 1f);
 	}
@@ -50,6 +54,13 @@ public class Mixer implements Audio {
 		pAudio.setVolume(pVolumeFactor * volume);
 	}
 
+	public void remove( Audio pAudio ) {
+	}
+
+	public void removeAll() {
+		audios.clear();
+	}
+
 	@Override
 	public boolean isPlaying() {
 		return audios.stream().anyMatch(aw -> aw.audio.isPlaying());
diff --git a/src/schule/ngb/zm/media/Music.java b/src/schule/ngb/zm/media/Music.java
index 1c53ba7..592a27e 100644
--- a/src/schule/ngb/zm/media/Music.java
+++ b/src/schule/ngb/zm/media/Music.java
@@ -1,5 +1,6 @@
 package schule.ngb.zm.media;
 
+import schule.ngb.zm.events.EventDispatcher;
 import schule.ngb.zm.tasks.TaskRunner;
 import schule.ngb.zm.util.ResourceStreamProvider;
 
@@ -27,10 +28,29 @@ public class Music implements Audio {
 
 	private float volume = 0.8f;
 
+	EventDispatcher<Audio, AudioListener> events;
+	{
+		events = new EventDispatcher<>();
+		events.registerEventType("start", (a,l) -> l.start(a));
+		events.registerEventType("stop", (a,l) -> l.stop(a));
+	}
+
 	public Music( String source ) {
 		this.audioSource = source;
 	}
 
+	public String getSource() {
+		return audioSource;
+	}
+
+	public void addListener( AudioListener listener ) {
+		events.addListener(listener);
+	}
+
+	public void removeListener( AudioListener listener ) {
+		events.removeListener(listener);
+	}
+
 	@Override
 	public boolean isPlaying() {
 		return playing;
@@ -119,6 +139,7 @@ public class Music implements Audio {
 	private void stream() {
 		audioLine.start();
 		playing = true;
+		events.dispatchEvent("start", Music.this);
 
 		byte[] bytesBuffer = new byte[BUFFER_SIZE];
 		int bytesRead = -1;
@@ -146,6 +167,7 @@ public class Music implements Audio {
 
 		playing = false;
 		streamingStopped();
+		events.dispatchEvent("stop", Music.this);
 	}
 
 	private boolean openLine() {
diff --git a/src/schule/ngb/zm/media/Sound.java b/src/schule/ngb/zm/media/Sound.java
index ceda917..e5c52c1 100644
--- a/src/schule/ngb/zm/media/Sound.java
+++ b/src/schule/ngb/zm/media/Sound.java
@@ -25,6 +25,10 @@ public class Sound implements Audio {
 		this.audioSource = source;
 	}
 
+	public String getSource() {
+		return audioSource;
+	}
+
 	public boolean isPlaying() {
 		// return audioClip != null && audioClip.isRunning();
 		return playing;
diff --git a/test/src/schule/ngb/zm/events/EventGeneratorTest.java b/test/src/schule/ngb/zm/events/EventDispatcherTest.java
similarity index 93%
rename from test/src/schule/ngb/zm/events/EventGeneratorTest.java
rename to test/src/schule/ngb/zm/events/EventDispatcherTest.java
index f10979b..97e3f8d 100644
--- a/test/src/schule/ngb/zm/events/EventGeneratorTest.java
+++ b/test/src/schule/ngb/zm/events/EventDispatcherTest.java
@@ -4,7 +4,7 @@ import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
 
-class EventGeneratorTest {
+class EventDispatcherTest {
 
 	class TestEvent {
 
@@ -37,7 +37,7 @@ class EventGeneratorTest {
 
 	@Test
 	void eventRegistry() {
-		EventGenerator<TestEvent, TestListener> gen = new EventGenerator<>();
+		EventDispatcher<TestEvent, TestListener> gen = new EventDispatcher<>();
 
 		gen.registerEventType("start", ( event, listener ) -> listener.startEvent(event));
 		gen.registerEventType("stop", ( event, listener ) -> listener.stopEvent(event));