Your current subs should deliver plenty of bass. Bass in a room is very dependent on sub placement. In your room the most likely best placement is on the short 12' wall. Place each sub up against the wall and 4' away from the front corners. Give that a try. Depending on where your main speakers are located in the room, you may have to play with Phase to deal with the time delay between the mains and subs. Also make sure you don't have the two subs out of phase from one another, if they are they can be cancelling each other out. Also don't cross your subs over too low. My experience has been the crossover points typically need to be between 50 and 80 Hz. Below 50 Hz, output can drop way off and above 80 Hz you can start audibly hearing where the subs are located, which is undesirable most times.
Seeking to Upgrade Subwoofer from SVS SB2000
My system consists of the following:
Martin Logan 11A Impressions loud speakers, Bryston 4B3 cubed amplifier, Rogue Audio Tube preamp, Lumin U2 mini streamer with LHY power supply, Chord Qutest DAC with S Booster Power supply. I have 2 SVS subwoofers model SB-1000, each retailing for $350.00. My upgrade sub budget for 2 subs are $1000.00 total. The Martin Logan is adjusted properly and I find the bass a bit weak. The current 2 subs help, but I would like to do better. Thank you.