Hi, I'm considering purchasing some m-audio av40 monitor speakers. I have a 2011 13" macbook pro. I'm looking for decent sound for general music listening, and also djing (traktor) and production (logic) Would I be advised to get an external sound card? If so, ideally would like a bus powered one (don't want to have to keep plugging things in!) I've looked at NI Audio 2 DJ and Behringer FCA202 Would they work?