title: iOS line in via headphone jack (adapter?)
body: <p>I want to record an audio signal with my Audio Unit on my iPhone which comes from a normal 3.5mm audio cable (e.g. with another iPhone acting as sound source).</p>
  
  <p>A direct line-in is not possible, because the iPhone has a 4 port headphone jack.
  I tried different kinds of these adapters:
  <a href="https://rads.stackoverflow.com/amzn/click/com/B004SP0WAQ" rel="nofollow noreferrer" rel="nofollow noreferrer">http://www.amazon.com/StarTech-com-headsets-separate-headphone-microphone/dp/B004SP0WAQ/ref=sr_1_3?ie=UTF8&amp;qid=1446196112&amp;sr=8-3&amp;keywords=3.5mm+headphone+mic+splitter</a></p>
  
  <p>But none of these worked.</p>
  
  <p>Am I doing something wrong?
  What else could I try?</p>
  
  <p>Thanks a lot and have a nice day!</p>