// deactivate session
BOOL success = [[AVAudioSession sharedInstance] setActive:NO error: nil];
if (!success) {
    NSLog(@"deactivationError");
}

// set audio session category AVAudioSessionCategoryPlayAndRecord options AVAudioSessionCategoryOptionAllowBluetooth
success = [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionAllowBluetooth error:nil];
if (!success) {
    NSLog(@"setCategoryError");
}

// activate audio session
success = [[AVAudioSession sharedInstance] setActive:YES error: nil];
if (!success) {
    NSLog(@"activationError");
}

return success;