Specka,
Which mode are you listening to music in (Pure Direct, Direct, Stereo, DPL-II, etc.)? If you're listening in Pure Direct or Direct, and assuming you have your speakers set to "Small", go the Advanced Menu for Direct mode setup and make sure you have the SW set to "LFE + MAIN". In the Direct mode, all bass below the x-over setting is lost unless SW is set to "LFE + MAIN". The 4306 should have more than enough power & control for your bass.