I want to record two voices and compare them. I think there is some Apple sample code for voice recording. I have no idea about comparing two audio files. What is the right app
It's not in objective C, but it does contain some fantastic explanation about how audio is compared by Shazam, and includes sample code (and source for a working application) in Java:
Check this out
Additionally, This Question has a fantastic link to audio fingerprinting, which is essentially the same as the article above, but more in depth.
Hope this helps