A small sub, 10” -12” driver, in a sealed enclosure cannot function well in a room that size. Any benefit of a sealed box is lost by the time you hit a room volume of about 3000’3. They simply do not have physics on their side.
Your best bet would be going ported with larger drivers. 2 PB2000 or PC2000 in your room would provide much more adequate output in a way that will maintain the clean, linear performance SVS subs are known for.
Truthfully, your room would benefit much more from bigger subs still.
I recognize your desire for low impact in your space and am trying to recommend accordingly.
If cost is the concern, I would try the SVS upgrade program to 1 PB or PC2000 now, then plan on adding the second later.
This isn’t about more bass, rather better response. You are asking and expecting that little SB to deliver well outside of its design. Chances are in turning the trim and gain up, you are likely driving it into some manner of distortion which is why you are likely experiencing the localization effect.
Larger subs designed for larger rooms will provide that response without having to boost them into potential distortion. Bass without distortion is subtle rather than loud.
