I m sorry guys but you all should upgrade your crap speakers. (Including the Bose coaxial owners)
The need of using other equalizer settings than "flat", indicates that your speakers have not a flat, smooth frequency response.
I m not trying to snob your sound system, its just an advice of good intention since i noticed you enjoy listening good (good = whatever everyone likes) music in your bella. To enjoy it much much more, you should upgrade your speakers with a set of woofer - tweeter - crossover of a danish, french, british or american brand. Your bella deserves it, you deserve it.