fill in asset based sound group if not specified by instanced emitter

Engine/source/T3D/sfx/sfxEmitter.cpp

@@ -840,6 +840,9 @@ void SFXEmitter::_update()
 
       if (mDirty.test(SourceGroup) && mInstanceDescription->mSourceGroup)
          mInstanceDescription->mSourceGroup->addObject(mSource);
+      else if (getSoundDescription() && getSoundDescription()->mSourceGroup)
+         getSoundDescription()->mSourceGroup->addObject(mSource);
+
       // Skip these 3d only settings.
       if(mInstanceDescription->mIs3D )
       {

Engine/source/gui/shiny/guiAudioCtrl.cpp

@@ -184,6 +184,8 @@ void GuiAudioCtrl::_update()
             mSoundPlaying->setFadeTimes(mFadeInTime, mFadeOutTime);
 
          }
+         else
+            getSoundDescription()->mSourceGroup->addObject(mSoundPlaying);
 
          mSoundPlaying->play();
       }