Mic not recognized on PS4 controller, Mac, phone, or external USB audio card.
TLDR: I've tried troubleshooting, Googling, adapters, etc. The PS4 controller just plain doesn't recognize the mic.
EDIT: Here is the adapter that makes it work with the PS4 and Mac/PC: https://amzn.to/2Sc8iUP
The longer version, just to save you the trouble I've had to go through:
I bought the headset based on old reviews that stated Massdrop had switched the headset cable from the tiny Sennheiser connector to a standard 3.5mm one. The headset I purchased and received in Jan 2018 is still using the tiny one. To make things worse, Sennheiser has discontinued both of the products that Massdrop recommends (in the stickied post) as a fix for this. So, you are going to receive a headset with a tiny cable adapter port, and a cable with the tiny plug on one end, and two red-pink/green 3.5mm plugs on the other end.
Since Sennheiser has discontinued both of the recommended adapters, then I ordered some 2-to-1 mic/audio adapters from Monoprice. Here's the thing, though...the Playstation 4 DS4 controller doesn't recognize the the mic, ever. Doesn't matter what combination of cables I use. Even if I just plug the red-pink one into the controller, it just thinks it's headphones. No mic. I've tried unplugging and replugging, plugging in different orders and at different stages of power and use, etc. When I plug the empty 2-to-1 adapter into the controller, the PS4 switches to the external mic, but when I plug the mic into the adapter, the PS4 still doesn't use it. When I plug the mic into the adapter BEFORE I plug the adapter into the controller, the PS4 doesn't switch the mic at all. I've tried it with the mic in mute position, in non-mute position, plugging, unplugging, power, blah blah blah. I've been an IT for 20 years...I know how to troubleshoot. The PS4 just plain doesn't recognize the mic when you try to plug it into the controller. I've tried three different adapters and two different controllers. I'm telling you, it just doesn't work.
I love the headset. Super comfy, lightweight, great mic, etc. Love everything about it. That is, aside from the fact that it has that tiny cable port and the PS4 won't recognize the mic.
I ended up buying an external USB sound card (the Roccat Juke) and it doesn't recognize the mic, either.