I have a pair of KRK vxt6 speaker which at the moment are connected to my headphone socket on my rMBP. I'm going to get a belkin thunderbolt dock that has a headpone jack. And I heard somewhere that the mac processes the signal better if a soundcard is used and plugged into the usb port. I might end up getting a cheap soundcard like the Behringer U-CONTROL UCA222, and plug that into the belkin and run the monitors though that. However as the belkin is connected via thunderbolt I was wondering if I would get better quality sound processing if I plugged the speakers into the headphone socket on the belkin rather than the headphone socket on the mac, and thus avoid using a soundcard.