An analog wheel that doesnt care what the PC or other device its connected to is. The return process was quick and efficient. I decided to go with the 7M (it was kind of a crap shoot) even though Teva recommends if you are a half size to go up. I kept my EQ in neutral as the natural response of these headphones has been so beautifully tuned - these are headphones for musicians. I am working from home and use a headset for phone calls. Der Effekt ist da und angenehm, aber nicht besonders deutlich. With impedance of 32 Ohms and sensitivity over 100dB , those are specifications that would have cost a lot more a few years ago, and for less than $10 is a steal! Every instrument sounds distinct in physical space around your head. Its incredibly entertaining for our tough chewer. Great replacement ear pads for the beats solo 3.