diff --git a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
index 8716e2075d..2fb42f4ef1 100644
--- a/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneObjectPart.cs
@@ -1336,11 +1336,13 @@ namespace OpenSim.Region.Framework.Scenes
             set { m_sitAnimation = value; }
         }
 
+        public UUID invalidCollisionSoundUUID = new UUID("ffffffff-ffff-ffff-ffff-ffffffffffff");
+
         public UUID CollisionSound
         {
             get { return m_collisionSound; }
             set
-            {
+            {           
                 m_collisionSound = value;
                 aggregateScriptEvents();
             }
@@ -2655,8 +2657,15 @@ namespace OpenSim.Region.Framework.Scenes
 
             bool IsNotVolumeDtc = !VolumeDetectActive;
 
-            if (startedColliders.Count > 0 && CollisionSound != UUID.Zero && CollisionSoundVolume > 0.0f && IsNotVolumeDtc)
-                SendSound(CollisionSound.ToString(), CollisionSoundVolume, true, (byte)0, 0, false, false);
+            if (IsNotVolumeDtc && startedColliders.Count > 0 && CollisionSoundVolume > 0.0f && CollisionSound != invalidCollisionSoundUUID)
+            {
+                if(CollisionSound != UUID.Zero)
+                    SendSound(CollisionSound.ToString(), CollisionSoundVolume, true, (byte)0, 0, false, false);
+                else
+                {
+                // default sounds
+                }
+            }
 
             SendCollisionEvent(scriptEvents.collision_start, startedColliders, ParentGroup.Scene.EventManager.TriggerScriptCollidingStart);
             if (IsNotVolumeDtc)
@@ -4743,7 +4752,7 @@ namespace OpenSim.Region.Framework.Scenes
 
             pa.OnCollisionUpdate -= PhysicsCollision;
 
-            bool hassound = ( CollisionSound != UUID.Zero && CollisionSoundVolume > 0.0f);
+            bool hassound = ( CollisionSound != invalidCollisionSoundUUID);
             scriptEvents CombinedEvents = AggregateScriptEvents;
 
             // merge with root part
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
index e18d9cfad9..eb68038e88 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
@@ -4779,7 +4779,13 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
         public void llCollisionSound(string impact_sound, double impact_volume)
         {
             m_host.AddScriptLPS(1);
-            
+
+            if(impact_sound == "")
+            {
+                m_host.CollisionSoundVolume = (float)impact_volume;
+                m_host.CollisionSound = m_host.invalidCollisionSoundUUID;
+                return;
+            }
             // TODO: Parameter check logic required.
             UUID soundId = UUID.Zero;
             if (!UUID.TryParse(impact_sound, out soundId))
@@ -4795,8 +4801,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                 }
                 m_host.TaskInventory.LockItemsForRead(false);
             }
-            m_host.CollisionSound = soundId;
             m_host.CollisionSoundVolume = (float)impact_volume;
+            m_host.CollisionSound = soundId;
         }
 
         public LSL_String llGetAnimation(string id)
diff --git a/OpenSim/Region/ScriptEngine/Shared/Instance/ScriptInstance.cs b/OpenSim/Region/ScriptEngine/Shared/Instance/ScriptInstance.cs
index ff1f277fbb..5e68d698e2 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Instance/ScriptInstance.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Instance/ScriptInstance.cs
@@ -847,6 +847,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Instance
             SceneObjectPart part = Engine.World.GetSceneObjectPart(LocalID);
             part.Inventory.GetInventoryItem(ItemID).PermsMask = 0;
             part.Inventory.GetInventoryItem(ItemID).PermsGranter = UUID.Zero;
+            part.CollisionSound = UUID.Zero;
             AsyncCommandManager.RemoveScript(Engine, LocalID, ItemID);
             EventQueue.Clear();
             m_Script.ResetVars();
@@ -873,6 +874,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Instance
             SceneObjectPart part = Engine.World.GetSceneObjectPart(LocalID);
             part.Inventory.GetInventoryItem(ItemID).PermsMask = 0;
             part.Inventory.GetInventoryItem(ItemID).PermsGranter = UUID.Zero;
+            part.CollisionSound = UUID.Zero;
             AsyncCommandManager.RemoveScript(Engine, LocalID, ItemID);
 
             EventQueue.Clear();