To record the sound in ios we can use the code below:-

To record the sound first set the delegate of AVAudioRecorder in AudioRecorderViewController.h File like

#import "AudioRecorderViewController.h"

@interface AudioRecorderViewController : UIViewController<AVAudioRecorderDelegate>

@interface AudioRecorderViewController : UIViewController<AVAudioRecorderDelegate>

This will be implemented in  "AudioRecorderViewController.m" file

AVAudioRecorder *_voicerecorder;

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
    NSError *err = nil;
    [audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
    if(err)
    {
        NSLog(@"audioSession: %@ %ld %@", [err domain], (long)[err code], [[err userInfo] description]);
        return;
    }
    [audioSession setActive:YES error:&err];
    err = nil;
    if(err)
    {
        NSLog(@"audioSession: %@ %ld %@", [err domain], (long)[err code], [[err userInfo] description]);
        return;
    }
    
   NSMutableDictionary  _recorderSettings = [[NSMutableDictionary alloc] init];
    [_recorderSettings setValue :[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
    [_recorderSettings setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
    [_recorderSettings setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
    [_recorderSettings setValue :[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
    [_recorderSettings setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
    [_recorderSettings setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
    _audioFileName = @"Sound";
    _recorderFilePath = [NSString stringWithFormat:@"%@/%@.wav", DOCUMENTS_FOLDER, _audioFileName] ;
    NSURL *url = [NSURL fileURLWithPath:_recorderFilePath];
    err = nil;
    _voicerecorder = [[ AVAudioRecorder alloc] initWithURL:url settings:_recorderSettings error:&err];
    if(!_voicerecorder){
        NSLog(@"recorder: %@ %ld %@", [err domain], (long)[err code], [[err userInfo] description]);
        [self showAlert:[err localizedDescription]] ;
        return;
    }
    
    [_voicerecorder setDelegate:self];
    [_voicerecorder prepareToRecord];
    _voicerecorder.meteringEnabled = YES;
    BOOL audioHWAvailable = audioSession.inputAvailable;
    if (! audioHWAvailable) {
        NSLog(@"input Hardware not supported");
        
        return;
    }
    
    // start recording
    
    [_voicerecorder record];

if you want to stop the recording then Use the code below

[_voicerecorder stop];

Here is the delegate method of the voiceRecorder that notifiy that the recording is successFull or not.
 

- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *) aRecorder successfully:(BOOL)flag
{
   if(flag){

NSLog(@"Recording finish success'");
} else{

NSLog(@"Recording finish fail'");
}  
}