[jdjdjdhhd]

You don't need any mods to make a speaker act as a microphone... Just like an LED doesn't need any mods to be a light sensor

[ace2358]

Not to the driver/microphone, but you do need to mod the circuitry it was attached to. And amplifier isn’t magically pre-amp.

[AlecSchueler]

I've tried it many times with many kinds of headphobes and it was always plug and play without any modifications.

[jdjdjdhhd]

Same with an alternator... Pretty sure it can be used both ways... The circuit can do both if designed right... That's childs play