diff --git a/Harmonia.Core/Caching/AudioImageMemoryCache.cs b/Harmonia.Core/Caching/AudioImageMemoryCache.cs
index e671863..1ab1510 100644
--- a/Harmonia.Core/Caching/AudioImageMemoryCache.cs
+++ b/Harmonia.Core/Caching/AudioImageMemoryCache.cs
@@ -5,6 +5,10 @@ namespace Harmonia.Core.Caching;
 
 public class AudioImageMemoryCache(IAudioImageExtractor audioImageExtractor) : MemoryCache<Song, SongPictureInfo>, IAudioImageCache
 {
+    protected override long? SizeLimit => 2000000000;
+    protected override double CompactionPercentage => 0.2;
+    protected override TimeSpan SlidingExpiration => TimeSpan.FromSeconds(600);
+
     protected override object? GetKey(Song key)
     {
         if (string.IsNullOrWhiteSpace(key.ImageHash) == false)
diff --git a/Harmonia.Core/Caching/MemoryCache.cs b/Harmonia.Core/Caching/MemoryCache.cs
index 091e964..5af8900 100644
--- a/Harmonia.Core/Caching/MemoryCache.cs
+++ b/Harmonia.Core/Caching/MemoryCache.cs
@@ -6,9 +6,9 @@ public abstract class MemoryCache<TKey, TValue> : Cache<TKey, TValue> where TKey
 {
     private readonly IMemoryCache _memoryCache;
 
-    protected virtual long? SizeLimit => 2000000000;
-    protected virtual double CompactionPercentage => 0.2;
-    protected virtual TimeSpan SlidingExpiration => TimeSpan.FromSeconds(600);
+    protected abstract long? SizeLimit { get; }
+    protected abstract double CompactionPercentage { get; }
+    protected abstract TimeSpan SlidingExpiration { get; }
 
     public MemoryCache()
     {