Hello, as mentioned in the manual page 121 and 123:
The input follows the CTIA, AHJ standard and has four segments; Tip=Headphone Left:Headphone Right (Ring 2): Ground (Ring 3) and Sleeve=Microphone.
Also on page 124 : It is possible to use headset microphones often bundled with mobile phones for themicrophone input, or clip-on lavalier microphones as long as they conform to the CTIA, AHJ standard
I personally already used the Sony Ps4 mic/headphones they provide with the console, it worked fine.
Also, please note that if you had only OMTP device (the other TRRS norm which inverts the ground and microphone wiring) it simply won't work. Luckily, OMTP/CTIA converters are available on the Market.
Here's some steps to experience vocoder stuff.
Go in utility menu and check mic settings :
Mic Gain should be default set to Auto Gain
Noise gate should be default set to -70dB
Mic detection should be default set to ON
Exit utility menu and load an init preset
once done change OSC type to vocoder ( it' s the latest one when browsing to the right)
Hold a note with your finger while speaking/singing in your mic , you should hear your vocoded voice.
If not, try to change Mic gain in utility settings.
Hope it helps,
best