title: How to control hardware mic input gain/level on iPhone?
body: <p>My audio-analysis function responds better on the iPad (2) than the iPhone (4). It seems sensitive to softer sounds on the iPad, whereas the iPhone requires much louder input to respond properly. Whether this is because of mic placement, different components, different software configurations or some other factor, I'd like to be able to control for it in my app.</p>
  
  <p>Obviously I could just multiply all of my audio samples to programmatically apply gain. Of course that has a software cost too, so:</p>
  
  <p>Is it possible to control the mic's gain from software in iOS, similarly to how it is in MacOS? I can't find any documentation on this but I'm hoping I'm just missing it somehow.</p>