What range sound frequency can be measured from iPhone's microphone?

I want to know the range of frequency that the iPhone's microphone can listen and can we play the least frequency sound re开发者_C百科corded by iPhone's microphone?

This web site has some iPhone 3G frequency response curves. Different device models have different mic frequency responses.

You can use any of AVRecorder, AudioQueue or AudioUnit RemoteIO APIs to record audio. See Apple's SpeakHere example app which includes source code for recording and saving to a file.