Separate/split audio from microphone

Discussion in 'iPhone Tips, Help and Troubleshooting' started by galenmd, Sep 18, 2008.

  1. galenmd macrumors regular

    Sep 11, 2008
    I am trying to create my own car kit. It is fairly easy to get the iPhone's calls to play through cars speakers (via FM transmitter or Aux input). Also, it seems that I get few complaints just having the iphone nearby and using the built in microphone. The problem I have is that when I plug in anything to the iPhone's jack, it disables the built-in microphone.

    Is there a cable that will not disable the built-in microphone? Alternatively, is there a cable that will allow me to split the signal so that I can send the audio into my car stereo (through my method of choice) and hook up an external microphone (to mount on my visor or wherever)?
  2. 00aggie macrumors newbie

    Dec 3, 2008
    I am working on a similar solution and was wondering what you may have found out. I'm certain there is no 3.5 mm jack that will not trip the mechanical switch within the iPhone's headphone jack that disables the mic. So I'm looking into hardwiring a mic around my visor.

    The iPhone 4 conductor pin out is here.

    I plan to plug my iphone into a 4 conductor 3.5 mm female jack that I will mount in my truck. From it, I'll split out mic/ground leads and connect them to a visor mic via shielded wiring. I have not yet found a mic that I like. The left/right/ground leads will connect into my stereo AUX input.

    Here's a link to a 4 conductor female jack:

    In case this set up experiences noise, I plan to add a noise filter. My only concern is how well the iPhone echo cancellers will remove any feedback from the truck speakers. An experiment of putting the ear pud next to the mic produces minimal or no echo, so I'm optimistic.

    The behavior of this set up, in theory, should be the same as wearing the stock iPhone headphones with built in mic. An incoming call would fade-out ipod audio and then pause. You would accept/reject the call on the iPhone. Caller would be heard over stereo speakers. After terminating the call, ipod audio would resume play and fade in. Pretty cool I think.

  3. G Young macrumors newbie

    Feb 19, 2005
    Separate/split audio from microphone

    this question should answer the question.

    Does the plug itself mechanically switch off the built in microphone. Or does it do it electrically by diverting or shorting out the microphone signal..

    If it is electrical, all you need is the 4 conductor plug, making sure the microphone conductor is dead (isn't connected to anything). Then you can use the built in microphone.

    Otherwise, if it is mechanical, then you need to hook up the microphone conductor to an external microphone.

    Let me know what you find out. I might want to do the same thing.

Share This Page