For anyone who runs into this old thread researching budget subwoofers. I just wanted to point out that Brent Butterworth measured both Dayton Audio Subs: SUB-1200 and SUB-1500 and chose the SUB-1200 as winner of his comparison with the following explanation:
https://thewirecutter.com/reviews/best-budget-subwoofer/#the-competition
That is really disappointing, because generally you would expect to gain substantial benefits going from a 12" to a 15" driver! That should be a no-brainer and it makes me wonder if they truly screwed something up on the design of the SUB-1500 ... or maybe they just "lucked up" with the SUB-1200 being so good as it is!
However, between the added size and cost of the SUB-1500, I suspect most will be better off with the SUB-1200.