I have a HK AVR30 aswell, with two JBL L20T bookshelves in the back, and Two JBL E60 tower speakers. I love the sound, good amount of bass. so, if your budget isnt too low, then try em out. i still enjoy em, even after having em for a year. hope you find your solution.
BTW, Harman/Kardon and JBL are meant to be together.