This newbie bought used Sierra 2's & Horizon center. What now? Subwoofer? Receiver?

[Jason08]

Thanks so much for your thoughts, martinm0.

I purchased an open box Denon X3800H from Adorama for $930. It was an improvement over the Yamaha TSR-700. However, I still feel like the sound is missing depth. Audyssey room correction helps but still lacking. I've considered adding an Emotiva BasX A3. I think my room is a big problem: it's an open-concept apartment with high ceilings and mostly hard surfaces.

I'm wondering if I should return the Denon X3800H and look for a used high-end receiver locally. I really have no idea what to look for, though. I'm only running a 3.1 system; future expansion possible to 5.2 at the most.

With the X3800H, I can upgrade to Dirac down the road.

EDIT:

Found these locally:
Anthem MRX720 $900
NAD T748 $200