Let me answer your question by telling you a story. I have a 13" MBP and I'm using 2 X1s and an Audio 8. The port closer to my screen is for my Audio 8 and I have a hub for the X1s. I have a powered hub that I normally use but last night I brought my non-powered one. With the non-powered hub, my X1s weren't nearly as responsive and the effects didn't work at all. So use a powered hub.

I use this one: http://www.tigerdirect.com/applicati...078&CatId=4753

It's powered, cheap, and works great.