Live mixer settings change works, but not instantly (playback buffer is filled in already).

ABStemPlayer/ViewModels/PlaybackViewModel.cs

@@ -1,4 +1,5 @@
 using System.Collections.ObjectModel;
+using System.ComponentModel;
 using System.Windows.Input;
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
@@ -132,6 +133,41 @@ public sealed partial class PlaybackViewModel : ObservableObject
         await _engine.PlayAsync();
     }
 
+    partial void OnMixerChanged(MixerViewModel? oldValue, MixerViewModel newValue)
+    {
+        if (oldValue != null)
+        {
+            foreach (var stem in oldValue.Stems)
+            {
+                stem.PropertyChanged -= OnMixerSettingsChanged;
+            }
+        }
+        if (newValue != null)
+        {
+            foreach (var stem in newValue.Stems)
+            {
+                stem.PropertyChanged += OnMixerSettingsChanged;
+            }
+        }
+    }
+
+    private void OnMixerSettingsChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        if (sender is not StemChannelViewModel stem)
+            return;
+
+        var mixerSettings = new MixerSettings
+        {
+            Stems = Mixer.Stems.Select(x => new StemMixSettings
+            {
+                GainDb  = x.GainDb,
+                Enabled = x.Enabled,
+                Pan     = x.Pan
+            }).ToList()
+        };
+        Task.Run(async () => await _engine.UpdateMixerAsync(mixerSettings));
+    }
+
     partial void OnCurrentTimeChanged(TimeSpan value)
     {
         foreach (var band in Bands)

ABStemPlayer/ViewModels/StemChannelViewModel.cs

@@ -5,8 +5,8 @@ public partial class StemChannelViewModel : ObservableObject
     public StemType Type { get; }
 
     [ObservableProperty] private bool  _enabled = true;
-    [ObservableProperty] private float _gainDb = 0f;
+    [ObservableProperty] private float _gainDb;
-    [ObservableProperty] private float _pan    = 0f;
+    [ObservableProperty] private float _pan;
 
     public StemChannelViewModel(StemType type)
     {

AudioCore/Models/MixerSettings.cs

@@ -5,6 +5,8 @@ public sealed class StemMixSettings
     public bool Enabled { get; init; } = true;
     public float GainDb { get; init; } = 0f;
     public float Pan { get; init; } = 0f; // -1..+1
+
+    public override string ToString() => $"{(Enabled ? "[x]": "[ ]")} {GainDb:N2} {Pan:N2}";
 }
 
 public sealed class MixerSettings