The attached image is a triumph of sorts as it shows the solution to a problem that has been driving me nuts the whole week.I wanted to connect an external, professional mic to an iPhone 4 (running iOS 5.1). Research showed me that the iPhone needed an external mic to have an impedance of at least 800 ohms or else it wouldn't switch over from the internal mic.
So I bought a cable on line from Sescom, via B&H. It arrived but wouldn't work. I was using a pro Sennheiser mic, but my iPhone just wouldn't switch over from the internal to the external.
I even pulled the XLR connector apart to see if it had the right impedance
matching circuit in it, which it did. The strange thing was that the mic and cable worked fine into my iPad.The solution is to insulate the base of the TRRS connector from touching the iPhone case. (The screwdriver is pointing to the offending part). Once this was done - Bingo! Worked fine. I now need to refine the solution and I have told the nice guys at Sescom how to do it. A small neoprene washer should do the trick. The supplied TRRS plug on the connecting cable is different from the ones A
pple supply, in that the Apple ones don't extend the sleeve connection to the base of the plug.This base (screwdriver blade in pic (L) indicates the offending area) comes into contact with the metal case/antenna that is around the iPhone. In effect it's then a connection between the 'sleeve' of the plug and the case. This obviously causes the audio circuits to malfunction and not switch over to this external input.
Nice to have worked it out.
