diff --git a/apps/openmw/mwclass/light.cpp b/apps/openmw/mwclass/light.cpp
index c45b11467..626cde9ac 100644
--- a/apps/openmw/mwclass/light.cpp
+++ b/apps/openmw/mwclass/light.cpp
@@ -250,7 +250,7 @@ namespace MWClass
         return std::make_pair(1,"");
     }
 
-    std::string Light::getSound(const MWWorld::Ptr& ptr) const
+    std::string Light::getSound(const MWWorld::ConstPtr& ptr) const
     {
       return ptr.get<ESM::Light>()->mBase->mSound;
     }
diff --git a/apps/openmw/mwclass/light.hpp b/apps/openmw/mwclass/light.hpp
index 02e327587..a52c3f568 100644
--- a/apps/openmw/mwclass/light.hpp
+++ b/apps/openmw/mwclass/light.hpp
@@ -73,7 +73,7 @@ namespace MWClass
 
             std::pair<int, std::string> canBeEquipped(const MWWorld::ConstPtr &ptr, const MWWorld::Ptr &npc) const;
 
-            virtual std::string getSound(const MWWorld::Ptr& ptr) const;
+            virtual std::string getSound(const MWWorld::ConstPtr& ptr) const;
     };
 }
 
diff --git a/apps/openmw/mwworld/class.cpp b/apps/openmw/mwworld/class.cpp
index 653163a4c..0617796f3 100644
--- a/apps/openmw/mwworld/class.cpp
+++ b/apps/openmw/mwworld/class.cpp
@@ -428,7 +428,7 @@ namespace MWWorld
         return getEncumbrance(ptr) / capacity;
     }
 
-    std::string Class::getSound(const MWWorld::Ptr&) const
+    std::string Class::getSound(const MWWorld::ConstPtr&) const
     {
       return std::string();
     }
diff --git a/apps/openmw/mwworld/class.hpp b/apps/openmw/mwworld/class.hpp
index 56dc7ede5..1873b2a0c 100644
--- a/apps/openmw/mwworld/class.hpp
+++ b/apps/openmw/mwworld/class.hpp
@@ -336,7 +336,7 @@ namespace MWWorld
             virtual void restock (const MWWorld::Ptr& ptr) const {}
 
             /// Returns sound id
-            virtual std::string getSound(const MWWorld::Ptr& ptr) const;
+            virtual std::string getSound(const MWWorld::ConstPtr& ptr) const;
 
             virtual int getBaseFightRating (const MWWorld::Ptr& ptr) const;