Something like these would be worth keeping an eye out for…
https://www.usaudiomart.com/details/650235646-atc-scm-19-v2/
Not sure you need to resort to DSP. Using some proven methods for sub placement and adjustment settings you should get a sub dialed in pretty well. Here are some helpful guidelines for placement and fine tuning fyi…
https://www.audioholics.com/home-theater-connection/crawling-for-bass-subwoofer-placement
1. Turn the Subwoofer Level control completely counterclockwise to its minimum; 2. Turn the Subwoofer Cut-Off Frequency control clockwise to its highest frequency (i.e. 150 Hz). 3. Set the Phase Alignment Control to 0°; 4. While you listen to a bass music or video selection in your primary listening area, have an assistant turn up the Subwoofer Level control until the subwoofer can be clearly heard; 5. Have an assistant try the Phase Alignment control until you hear the most bass. Your subwoofer and front speakers are now in phase. Do not change phase alignment again unless you move the subwoofer or the front speakers to a different location in the room or move or remove large items of furniture or room furnishings (i.e. carpet, draperies, etc.) 6. Turn the Subwoofer Level control completely counterclockwise to its minimum.
7. Turn the Subwoofer Cut-Off Frequency control completely counter-clockwise to its lowest frequency (i.e. 50 Hz); 8. Slowly rotate the Subwoofer Level control until you match the subwoofer output level with the level of your front speakers. Bass should be clearly audible, but not intrusive; NOTE: If using an A/V receiver or processor to control crossover setting, skip the next step and set the subwoofer cutoff frequency control to ‘Bypass.’ 9. Slowly rotate the Subwoofer Cut-Off Frequency control until you hear the best subwoofer/main speaker blend. If the sound is too ‘thin,’ you have not set the frequency high enough; if the sound becomes ‘boomy’ you have set the frequency too high. Adjust until you find the most natural balance. The sub should not draw attention to itself.