I am looking to get another set of bookshelf speakers for my set up. I mainly listen to music and will use for home theater every once in a while. I am thinking of getting either the RTi A 1 or 3, or the RTi 4. Which one sound better for music, I listen to rock, techno, and rap. I already have PSW505, CSi3, and RTi A1. What set of bookshelf speakers should I get?