In an attempt to be helpful to the OP I want to present the research data from Harman regarding multiple subs. The research is extensive with computer modeling and multiple variations in numbers and placement. It’s easy find online and well worth the reading. Multiple subs are not a cult but are scientifically proven to even out bass nodes but are they really necessary? Where do you want to spend your limited funds? Here is their conclusion:
” Four subwoofers are enough to get the best results of any configuration tried. Two subwoofers is very nearly as good and has very good low frequency support as well.”
The midrange is where most of the fidelity in reproduced recordings lies, in my opinion. Proper speaker positioning and an excellent midrange would be my first goal. If money is left over considering amplification, room treatments, cabling and two matched subs, then get two more. But as their research shows you can do very well with two high quality matched subs.
” Four subwoofers are enough to get the best results of any configuration tried. Two subwoofers is very nearly as good and has very good low frequency support as well.”
The midrange is where most of the fidelity in reproduced recordings lies, in my opinion. Proper speaker positioning and an excellent midrange would be my first goal. If money is left over considering amplification, room treatments, cabling and two matched subs, then get two more. But as their research shows you can do very well with two high quality matched subs.