Assuming most panel speakers thrive on current Coda Amplifiers might be a sensibly priced locally produced and serviced candidate.
Multiple smaller sealed subwoofers Crawl Tested locations dramatically reduced my rooms modes.
If the goal with your subwoofers is to match your main speakers or any future speakers sonic presentation through the crossover region you'll need to find processing that includes auto/manual parametric frequency, slope, Q, and gain.
Adjusting variable phase and a hard crossover frequency forces you to reduce the subs gain just to get a small sense of integration matching.
If satisfied you'll save money and have no idea what your missing.
Multiple smaller sealed subwoofers Crawl Tested locations dramatically reduced my rooms modes.
If the goal with your subwoofers is to match your main speakers or any future speakers sonic presentation through the crossover region you'll need to find processing that includes auto/manual parametric frequency, slope, Q, and gain.
Adjusting variable phase and a hard crossover frequency forces you to reduce the subs gain just to get a small sense of integration matching.
If satisfied you'll save money and have no idea what your missing.