I’m not very satisfied with the sound quality of my Toshiba Qosmio F25..

What can I do?

I use Sony MDR-V900 Monitor Series Headphones

http://www.amazon.com/gp/product/B00001W0D5/sr=1-1/qid=1138228682/ref=pd_bbs_1/104-0485667-2393511?%5Fencoding=UTF8