There are great sub dsp solutions, but they won’t work for you. With two subs, you should be able to address virtually all room modes at your listening position by placement. I would get room eq and purchase the needed microphone ($60) as it makes it much faster to measure and test the effects of moving your subs, as well as changing their polarity. If you are still having issues, adding a third well placed sub is probably the most cost effective way to lessen the modes.
Also, room eq will allow you to view your decay time at various frequencies and use targeted frequency bass traps for modes and slow decay.
Alternatively, you could change subs to a pair with built in eq or parametric or add an outboard dsp. Keep the crossover for the mains, run the subs from the second output on your preamp (or y connector if none). I would try the above first.
Also, room eq will allow you to view your decay time at various frequencies and use targeted frequency bass traps for modes and slow decay.
Alternatively, you could change subs to a pair with built in eq or parametric or add an outboard dsp. Keep the crossover for the mains, run the subs from the second output on your preamp (or y connector if none). I would try the above first.