diff --git a/osu.Game.Modes.Catch/CatchRuleset.cs b/osu.Game.Modes.Catch/CatchRuleset.cs
index 2cdd35cf3a..f3eda9ff37 100644
--- a/osu.Game.Modes.Catch/CatchRuleset.cs
+++ b/osu.Game.Modes.Catch/CatchRuleset.cs
@@ -93,9 +93,9 @@ namespace osu.Game.Modes.Catch
 
         public override DifficultyCalculator CreateDifficultyCalculator(Beatmap beatmap) => new CatchDifficultyCalculator(beatmap);
 
-        public override IBeatmapConverter<CatchBaseHit> CreateBeatmapConverter<CatchBaseHit>()
+        public override IBeatmapConverter<T> CreateBeatmapConverter<T>()
         {
-            return (IBeatmapConverter<CatchBaseHit>)new CatchBeatmapConverter();
+            return (IBeatmapConverter<T>)new CatchBeatmapConverter();
         }
     }
 }
diff --git a/osu.Game.Modes.Mania/ManiaDifficultyCalculator.cs b/osu.Game.Modes.Mania/ManiaDifficultyCalculator.cs
index 07c0749904..7ee93b84cf 100644
--- a/osu.Game.Modes.Mania/ManiaDifficultyCalculator.cs
+++ b/osu.Game.Modes.Mania/ManiaDifficultyCalculator.cs
@@ -12,11 +12,9 @@ namespace osu.Game.Modes.Mania
     {
         protected override PlayMode PlayMode => PlayMode.Mania;
 
-        private int columns;
-
-        public ManiaDifficultyCalculator(Beatmap beatmap, int columns = 5) : base(beatmap)
+        public ManiaDifficultyCalculator(Beatmap beatmap)
+            : base(beatmap)
         {
-            this.columns = columns;
         }
 
         protected override double CalculateInternal(Dictionary<String, String> categoryDifficulty)
diff --git a/osu.Game.Modes.Mania/ManiaRuleset.cs b/osu.Game.Modes.Mania/ManiaRuleset.cs
index 7d88942798..0aef44cd7b 100644
--- a/osu.Game.Modes.Mania/ManiaRuleset.cs
+++ b/osu.Game.Modes.Mania/ManiaRuleset.cs
@@ -108,9 +108,9 @@ namespace osu.Game.Modes.Mania
 
         public override DifficultyCalculator CreateDifficultyCalculator(Beatmap beatmap) => new ManiaDifficultyCalculator(beatmap);
 
-        public override IBeatmapConverter<ManiaBaseHit> CreateBeatmapConverter<ManiaBaseHit>()
+        public override IBeatmapConverter<T> CreateBeatmapConverter<T>()
         {
-            return (IBeatmapConverter<ManiaBaseHit>)new ManiaBeatmapConverter();
+            return (IBeatmapConverter<T>)new ManiaBeatmapConverter();
         }
     }
 }
diff --git a/osu.Game.Modes.Osu/OsuRuleset.cs b/osu.Game.Modes.Osu/OsuRuleset.cs
index 33427e0f55..a61bda5bb3 100644
--- a/osu.Game.Modes.Osu/OsuRuleset.cs
+++ b/osu.Game.Modes.Osu/OsuRuleset.cs
@@ -120,9 +120,9 @@ namespace osu.Game.Modes.Osu
             new KeyCounterMouse(MouseButton.Right)
         };
 
-        public override IBeatmapConverter<OsuHitObject> CreateBeatmapConverter<OsuHitObject>()
+        public override IBeatmapConverter<T> CreateBeatmapConverter<T>()
         {
-            return (IBeatmapConverter<OsuHitObject>)new OsuBeatmapConverter();
+            return (IBeatmapConverter<T>)new OsuBeatmapConverter();
         }
     }
 }
diff --git a/osu.Game.Modes.Taiko/TaikoRuleset.cs b/osu.Game.Modes.Taiko/TaikoRuleset.cs
index 4bca82a70b..3765862229 100644
--- a/osu.Game.Modes.Taiko/TaikoRuleset.cs
+++ b/osu.Game.Modes.Taiko/TaikoRuleset.cs
@@ -94,9 +94,9 @@ namespace osu.Game.Modes.Taiko
 
         public override DifficultyCalculator CreateDifficultyCalculator(Beatmap beatmap) => new TaikoDifficultyCalculator(beatmap);
 
-        public override IBeatmapConverter<TaikoBaseHit> CreateBeatmapConverter<TaikoBaseHit>()
+        public override IBeatmapConverter<T> CreateBeatmapConverter<T>()
         {
-            return (IBeatmapConverter<TaikoBaseHit>)new TaikoBeatmapConverter();
+            return (IBeatmapConverter<T>)new TaikoBeatmapConverter();
         }
     }
 }
diff --git a/osu.Game/Beatmaps/Beatmap.cs b/osu.Game/Beatmaps/Beatmap.cs
index 1fa4a1f7b8..94a56231f0 100644
--- a/osu.Game/Beatmaps/Beatmap.cs
+++ b/osu.Game/Beatmaps/Beatmap.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using osu.Game.Beatmaps.Timing;
-using osu.Game.Database;
 using osu.Game.Modes;
 using osu.Game.Modes.Objects;
 using System.Collections.Generic;