I would say the soundstage and dynamics to be the same. The Theatres have a bit of edge in that they can take more power (and play louder) without sounding busy. One thing I found is that the Theatres have a less forward sound than the Towers.Sorry, but I don't quite understand the description of "narrow" bass. If by narrow, you mean soundstage, it's more likely a room placement issue. Or do you mean narrow as in frequency range (ie bass is dominated by one particular frequency).