diff --git a/OpenSim/Region/Framework/Scenes/CollisionSounds.cs b/OpenSim/Region/Framework/Scenes/CollisionSounds.cs
index 078449bd93..84817a050b 100644
--- a/OpenSim/Region/Framework/Scenes/CollisionSounds.cs
+++ b/OpenSim/Region/Framework/Scenes/CollisionSounds.cs
@@ -129,8 +129,6 @@ namespace OpenSim.Region.Framework.Scenes
                 return;
 
             float volume = part.CollisionSoundVolume;
-            if (volume == 0.0f)
-                return;
 
             UUID soundID = part.CollisionSound;
 
@@ -150,6 +148,9 @@ namespace OpenSim.Region.Framework.Scenes
                     break;
             }
 
+            if (volume == 0.0f)
+                return;
+
             bool doneownsound = false;
 
             int thisMaterial = (int)part.Material;
diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
index 9b7374c048..b7c5b6b35b 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs
@@ -2112,6 +2112,12 @@ namespace OpenSim.Region.Framework.Scenes
             d.AddActiveScripts(count);
         }
 
+        private const scriptEvents PhysicsNeeedSubsEvents = (
+            scriptEvents.collision | scriptEvents.collision_start | scriptEvents.collision_end |
+            scriptEvents.land_collision | scriptEvents.land_collision_start | scriptEvents.land_collision_end);
+
+        private scriptEvents lastRootPartPhysEvents = 0;
+
         public void aggregateScriptEvents()
         {
             PrimFlags objectflagupdate = (PrimFlags)RootPart.GetEffectiveObjectFlags();
@@ -2148,6 +2154,20 @@ namespace OpenSim.Region.Framework.Scenes
                 m_scene.RemoveGroupTarget(this);
             }
 
+            scriptEvents rootPartPhysEvents = RootPart.AggregateScriptEvents;
+            rootPartPhysEvents &= PhysicsNeeedSubsEvents;
+            if (rootPartPhysEvents != lastRootPartPhysEvents)
+            {
+                lastRootPartPhysEvents = rootPartPhysEvents;
+                for (int i = 0; i < parts.Length; i++)
+                {
+                    SceneObjectPart part = parts[i];
+                    if (part == null)
+                        continue;
+                    part.UpdatePhysicsSubscribedEvents();
+                }
+            }
+
             ScheduleGroupForFullUpdate();
         }
 
diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
index dd20a2ffb3..fcc3463b48 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
@@ -1534,7 +1534,6 @@ namespace OpenSim.Region.Framework.Scenes
                 else
                     m_collisionSoundType = 1;
 
-                aggregateScriptEvents();
             }
         }
 
@@ -5033,7 +5032,7 @@ SendFullUpdateToClient(remoteClient, Position) ignores position parameter
         }
 
 
-        private void UpdatePhysicsSubscribedEvents()
+        internal void UpdatePhysicsSubscribedEvents()
         {
             PhysicsActor pa = PhysActor;
             if (pa == null)
@@ -5107,8 +5106,6 @@ SendFullUpdateToClient(remoteClient, Position) ignores position parameter
                 objectflagupdate |= (uint) PrimFlags.AllowInventoryDrop;
             }
 
-            UpdatePhysicsSubscribedEvents();
-
             LocalFlags = (PrimFlags)objectflagupdate;
 
             if (ParentGroup != null && ParentGroup.RootPart == this)
@@ -5119,6 +5116,7 @@ SendFullUpdateToClient(remoteClient, Position) ignores position parameter
             {
 //                m_log.DebugFormat(
 //                    "[SCENE OBJECT PART]: Scheduling part {0} {1} for full update in aggregateScriptEvents()", Name, LocalId);
+                UpdatePhysicsSubscribedEvents();
                 ScheduleFullUpdate();
             }
         }
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index 914644ab73..50ee9d4219 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -1246,7 +1246,7 @@ namespace OpenSim.Region.Framework.Scenes
                                         physActor_OnPhysicsRequestingCameraData;
                             partPhysActor.OnPhysicsRequestingCameraData +=
                                         physActor_OnPhysicsRequestingCameraData;
-                         }
+                        }
                     }
                     ParentUUID = UUID.Zero;
                 }
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
index c046a0c52e..66cb30c5ec 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
@@ -5109,6 +5109,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                 m_host.CollisionSoundVolume = (float)impact_volume;
                 m_host.CollisionSound = m_host.invalidCollisionSoundUUID;
                 m_host.CollisionSoundType = -1; // disable all sounds
+                m_host.aggregateScriptEvents();
                 return;
             }
 
@@ -5122,6 +5123,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             }
             else
                  m_host.CollisionSoundType = -1;
+
+            m_host.aggregateScriptEvents();
         }
 
         public LSL_String llGetAnimation(string id)
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
index 6168fe03d2..4af433926d 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/OSSL_Api.cs
@@ -4266,6 +4266,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                     m_host.CollisionSoundType = 0; // full return to default sounds
                 else
                     m_host.CollisionSoundType = 2; // default sounds with volume
+                m_host.aggregateScriptEvents();           
                 return;
             }
             // TODO: Parameter check logic required.
@@ -4278,6 +4279,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             }
             else
                  m_host.CollisionSoundType = -1;
+
+            m_host.aggregateScriptEvents();           
         }
 
         // still not very usefull, detector is lost on rez, restarts, etc