diff --git a/Lib.Audio/Channel.cs b/Lib.Audio/Channel.cs
index 712a45a..ad91bde 100644
--- a/Lib.Audio/Channel.cs
+++ b/Lib.Audio/Channel.cs
@@ -28,7 +28,7 @@ namespace Lib.Audio
         public IFader Fader { get; }
         public IKnob Knob { get; }
         public List<IButton> Buttons { get; }
-        public IControllable Controllable { get; private set; }
+        public IControllable? Controllable { get; private set; }
         
         public void AllocateControllable(IControllable controllable) => Controllable = controllable;
 
@@ -42,6 +42,6 @@ namespace Lib.Audio
             return buttons;
         }
         
-        private void OnFaderPositionChanged(object? sender, float position) => Controllable.SetVolume(position);
+        private void OnFaderPositionChanged(object? sender, float position) => Controllable?.SetVolume(position);
     }
 }
\ No newline at end of file
diff --git a/Lib.Audio/Controls/Fader.cs b/Lib.Audio/Controls/Fader.cs
index cba245a..15aee42 100644
--- a/Lib.Audio/Controls/Fader.cs
+++ b/Lib.Audio/Controls/Fader.cs
@@ -21,6 +21,6 @@ namespace Lib.Audio.Controls
             }
         }
 
-        public event EventHandler<float> PositionChanged;
+        public event EventHandler<float>? PositionChanged;
     }
 }
\ No newline at end of file
diff --git a/Lib.Audio/Controls/Interfaces/IFader.cs b/Lib.Audio/Controls/Interfaces/IFader.cs
index 475bb50..b14d440 100644
--- a/Lib.Audio/Controls/Interfaces/IFader.cs
+++ b/Lib.Audio/Controls/Interfaces/IFader.cs
@@ -10,6 +10,6 @@ namespace Lib.Audio.Controls.Interfaces
     {
         float Position { get; } //TODO: float or double?
 
-        event EventHandler<float> PositionChanged;
+        event EventHandler<float>? PositionChanged;
     }
 }
\ No newline at end of file
diff --git a/Lib.Audio/Interfaces/IChannel.cs b/Lib.Audio/Interfaces/IChannel.cs
index 80b712a..789e8d3 100644
--- a/Lib.Audio/Interfaces/IChannel.cs
+++ b/Lib.Audio/Interfaces/IChannel.cs
@@ -14,7 +14,7 @@ namespace Lib.Audio.Interfaces
         IKnob Knob { get; }
         List<IButton> Buttons { get; }
         
-        IControllable Controllable { get; }
+        IControllable? Controllable { get; }
 
         void AllocateControllable(IControllable controllable);
     }