I'm trying to find a way to connect an external 3.5mm mic to my i9100 using a variable resistor (eg a volume controller in this case) to add impedance so that various mics with their different impedances can be connected freely, rather than just adding an inline resistor of arbitrary value.

A splitter like like could work perhaps:

I was just checking out this thread for a similar hack:

and it says that impedance needs to be added in line with the mic so that the device recognises the mic as a mic (has to be above 1000 Ohms).

This has me wondering if, instead of adding a resistor in the cable that goes to the mic jack (or in the cable of the mic itself), it would be possible to use the splitting adapter above and plug a volume controller like the one below into the mic jack of the splitting adapter then the mic to the other end, like this:

Using the volume controller I can change the resistance between the tip connections of that cable, from 0 up to 1250 ohms, and then it jumps to infinity.

In the above photo the adapter is designed for nokias (OMTP) so the TRRS pinout is different to the i9100 (CTIA).

If I get a CTIA TRRS adapter, will I be abe to make this work using the volume controller?