MusicXML 4.1 Draft
MusicXML 4.1 Draft > MusicXML Reference > Examples > <effect>

<effect>

effect-element

<direction placement="above">
   <direction-type>
      <percussion default-y="36" halign="center" relative-x="4">
         <effect>cannon</effect>
      </percussion>
   </direction-type>
</direction>