How to reduce recording noise when recording with audio sessions?

I got some recording code working, but the recorded audio (from the iPod touch internal microphone) is very noisy.

This is my configuration:

    AVAudioSession *audioSession = [AVAudioSession sharedInstance];
    NSError *err = nil;
    [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&err];
    if (err) {
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        return;
    }
    [audioSession setActive:YES error:&err];
    err = nil;
    if (err) {
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        return;
    }

    recordSetting = [[NSMutableDictionary alloc] init];

    // We can use kAudioFormatAppleIMA4 (4:1 compression) or kAudioFormatLinearPCM for nocompression
    [recordSetting setValue:[NSNumber kAudioFormatLinearPCM] forKey:AVFormatIDKey];

    // We can use 44100, 32000, 24000, 16000 or 12000 depending on sound quality
    [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];

    // We can use 2 (if using additional h/w) or 1 (iPhone only has one microphone)
    [recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];

    // These settings are used if we are using kAudioFormatLinearPCM format
    [recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
    [recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
    [recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];

Do I have bad config here or is there a different way to reduce noise in the recorded audio? There are some voice recorder apps out there that are noise free as far as I can tell.