Iujona,
You don't say which model of Nautilus speaker unless you are one of the rare few that have "The" Nautilus speaker. I own N804's, I used to have N805's, A co-worker also has N804's and my brother has N803's so I've listened to a few different systems with this series speaker.
I would suspect your room is the culprit. In my smallish, fairly well damped room the N804's are, if anything, a bit bass shy. Particularly in the lowest region. In my co-worker's larger room the N804's go deeper with more authority than in my room. They are by no means boomy in his room. My brother has a huge room with cathedral ceilings and his N803's are wonderfully balanced (lucky @*@%). I might add that Sound Anchor Stands have greatly improved every B&W set-up I have heard. The improvements are not subtle.
You may have a synergy issue whereby you would need to fix the room, work with placement and coupling to the floor or look elsewhere for speakers.
I hope some of this is useful. Good luck!
Woodrow