[plt-scheme] Problem with play-sound

Hi all ,

I made a little game which needs to play sound ,
It works fine like this :

(play-sound (build-path (current-directory) "sounds" "sound1.wav"))

But when I do it Twice , the first sound is stopped before it terminates
when the second sound began to play ...
So I try to make new thread each time sound is played , like this :

(thread (lambda ()  (play-sound (build-path (current-directory) "sounds"
"sound1.wav")))

But it did the same thing .

Anyone has any ideas ?