How to filter background noise while recording audio using AVAudiorecorder in ios?

I'm creating an app something like Talking Tom. I can record and play it again using AVAudioplayer/recorder but voice is not clear as background noises are dominating.

Can anyone please tell me how to remove/filter the noises so that recorded voice will be clear.

Can you filter out background noise on iPhone?

Go to the Effects tab of the iMovie app and select Audio Filters. Click on the Noise Reduction tool and drag the slider to the right to reduce background noise.

For the most part iOS does noise cancellation internally and I think it is doing it automatically.

The normal approach is to have two microphones and then subtract the wave from the one picking up ambient noise from the one that is oicking up the user.

However iOS only exposes a single microphone via AV Foundation (on my iPhone 5) and thus you have to live with the quality that you are getting.