It doesn't have one.
Hm, right. Instead i could use a GinSing-Shiled (http://www.ginsingsound.com/).
Is this an assignment you have been given?
No. What i meant was: The sound must (if somehow possible) be created without a external synthesizer. It is an artprojekt for a festival in the desert. And i think a laptop would not survive the extreme conditions.
My target ist to put al the needet parts (Arduino, shield(s), sensors, batteries and the amplifier) in just one case and seal it.