Problem with "Click Sound" on button click in iPhone

i am working in the project in which i face the problem of playing the clicking sound on button click, i have done the following code on TouchDown Event of Buttons on every page

-(IBActi开发者_Go百科on)ClickButtonSound:(id)sender
 {
     SystemSoundID theSound;
     NSString *pathToSound;
     pathToSound = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"buttonsound" ofType:@"wav"] isDirectory:NO];
     OSStatus error = AudioServicesCreateSystemSoundID((CFURLRef)pathToSound,&theSound);
     NSLog(@"error=%@",error);
      AudioServicesPlaySystemSound (theSound);
     //[pathToSound release];

 }

this code is working well on simulator but when i test it on iphone device it gives humming sound,but not plays clicking sound so can anyone plese point out the reason why it is so? thanks

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Are you sure you stop the sound from playing when you get the TouchUpEvent?