I am not familiar with Media Slayer. I will tell you that it takes a lot of "juice" to drive the Senn's. If you're talking about an output of 500-750 mVolt...forget about it! It will take about a 2 volt output [DAC] into a headphone amp to really appreciate the Senn's...otherwise, WAY too low volume.
Your friend might want to try a pair of Grado 125's, if he's going to go with a low voltage output. They'll play MUCH louder than the Senn's.
Your friend might want to try a pair of Grado 125's, if he's going to go with a low voltage output. They'll play MUCH louder than the Senn's.