Connecting a piezo mic directly to the iPhone TRRS headphone. Beginers Question.

Hi,

I am a student and I am new to Max and the forum, so I hope this isn,t a repeat question. I researching using max for synth app, controlled by gestures played on surfaces, and I have a question regarding using hardware with it on an iPhone.

I am trying to figure out a way which I can utilise the TRRS headphone input to connect a contact mic and use the headphones at the same time. I have used the "IRig" and units like it, designed to plug instruments in and monitor in headphones. While these devices work, I am finding at the sensitivity levels involved in this application these have feedback issues?

I believe the iPhone requires a Low Impedance to, If you like switch to the TRRS and allow the mono mic input as well as headphones. I read on apples site this is no higher than 32 ohms?

My question is, does anyone know of a simple solution to take a high Z direct from piezo and convert to the level Apple specifies for the TRRS?

And any more specific information about the TRRS and how it works, i.e having it correctly set-up so when you plug it in the headphones it switches automatically.

I would like to not add any D.I boxes or Pre-amp's, something that would be compact and hopefully cheap.

Sorry for the beginners post.

Thanks,

Pete.