Make SampleInfo choose its own lookup name

osu.Game/Audio/SampleInfo.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
+using System.Collections.Generic;
 
 namespace osu.Game.Audio
 {
@@ -33,6 +34,12 @@ namespace osu.Game.Audio
         /// </summary>
         public int Volume;
 
+        public virtual IEnumerable<string> LookupNames => new[]
+        {
+            $"{Namespace}/{Bank}-{Name}",
+            $"{Bank}-{Name}" // Without namespace as a fallback
+        };
+
         public SampleInfo Clone() => (SampleInfo)MemberwiseClone();
     }
 }

osu.Game/Skinning/SkinnableSound.cs

@@ -44,19 +44,17 @@ namespace osu.Game.Skinning
 
         private SampleChannel loadChannel(SampleInfo info, Func<string, SampleChannel> getSampleFunction)
         {
-            SampleChannel ch = null;
+            foreach (var lookup in info.LookupNames)
+            {
+                var ch = getSampleFunction($"Gameplay/{lookup}");
+                if (ch == null)
+                    continue;
 
-            if (info.Namespace != null)
-                ch = getSampleFunction($"Gameplay/{info.Namespace}/{info.Bank}-{info.Name}");
-
-            // try without namespace as a fallback.
-            if (ch == null)
-                ch = getSampleFunction($"Gameplay/{info.Bank}-{info.Name}");
-
-            if (ch != null)
                 ch.Volume.Value = info.Volume / 100.0;
+                return ch;
+            }
 
-            return ch;
+            return null;
         }
     }
 }