diff --git a/src/ObjCRuntime/Dlfcn.cs b/src/ObjCRuntime/Dlfcn.cs
index 48cc2ba31a3..354fcaa2b16 100644
--- a/src/ObjCRuntime/Dlfcn.cs
+++ b/src/ObjCRuntime/Dlfcn.cs
@@ -55,9 +55,6 @@ static public class OpenGLES {
 			static public readonly IntPtr Handle = Dlfcn._dlopen (Constants.OpenGLESLibrary, 0);
 		}
 #endif
-		static public class AudioToolbox {
-			static public readonly IntPtr Handle = Dlfcn._dlopen (Constants.AudioToolboxLibrary, 0);
-		}
 #endif
 	}
 
diff --git a/src/audiounit.cs b/src/audiounit.cs
index 1054187fdd6..95350184b93 100644
--- a/src/audiounit.cs
+++ b/src/audiounit.cs
@@ -527,10 +527,10 @@ AUParameterTree ParameterTree {
 		[Export ("shouldChangeToFormat:forBus:")]
 		bool ShouldChangeToFormat (AVAudioFormat format, AUAudioUnitBus bus);
 
-		[Notification, Field ("kAudioComponentRegistrationsChangedNotification")]
+		[Notification, Field ("kAudioComponentRegistrationsChangedNotification", "AudioToolbox")]
 		NSString AudioComponentRegistrationsChangedNotification { get; }
 
-		[Notification, Field ("kAudioComponentInstanceInvalidationNotification")]
+		[Notification, Field ("kAudioComponentInstanceInvalidationNotification", "AudioToolbox")]
 		NSString AudioComponentInstanceInvalidationNotification { get; }
 
 		/// <summary>To be added.</summary>