I'm looking to buy a large 15" sub or dual subs and I'm wondering if with that much low output do I still need my studio 100's. I originaly bought them because I wasn't getting a sub and wanted to cover the lows better. So with a sub I'm thinking I could get a pair of big bookshelf speakers that are better quality than my 100's or would I need the towers to covers the mids better? I listen to music like NIN, Tool, Crystal Method, mostly rock and some rap. Thanks -Mark