The audio setup I'm using in this case is:
Audio card: Sound Blaster ZxR
Headset: Sennheiser G4ME Zero
The headset is rated at 150 Ohms of impedance.
The audio card has 2 impedance settings: 32 Ohms for most standard headphones, and 600 Ohms for high-end headphones. I've been using it at 32...