iphone - iphone:Apply voice modulation and save that modulated sound file

Question

In my app I am using DIRAC framework for voice modulation now I want to save that modulated sound file to my document directory. I am a little confused as to how to save that modulated file?

Here is my code that modulate the sound file and play that file.

-(IBAction)uiPitchSliderMoved:(UISlider *)sender;
 {
    [mDiracAudioPlayer stop];   // only required in LE!
    [mDiracAudioPlayer changePitch:powf(2.f, (int)sender.value / 12.f)];
    uiPitchLabel.text = [NSString stringWithFormat:@"%d", (int)sender.value];
    NSLog(@"pitchlabel=%@",uiPitchLabel.text);
    [mDiracAudioPlayer play];   // only required in LE!
 }

I wnat to save the audio file when pitch rate is changed.