Teufel Cage
Cable
Question about Teufel Cage
Do I have to connect the headphones via USB cable to use the microphone? In that case, wouldn't I have to do without the sound card on my PC?
No, you don't have to.
There is also a cable that is a 3.5 mm 4-pin jack, just like on smartphones. You might have to buy a splitter if the sound card does not support such combo connections.
E.g. such an adapter: Lindy Headphone-PC adapter cable (stereo, headset adapter)