Which Subwoofer would you choose?


Hello everyone I’m seeking some advice on which subwoofer would be ideal. First off my tv room size is rather large, 20x20 connected to an open kitchen currently I have (2) Klipsch RP280F towers and an Onkyo TX-NR708 receiver, my budget is around $275.00 (Shipped) for a sub I found these 2 subs used locally both in good condition

Velodyne VRP-12 12" $120.00
Velodyne SPL-1500R 15" $275.00

I’m not sure if SPL or VRP is better? or if the prices of these are not worth it? Can I get something better for $275.00? any advice would help! thanks in advance.
mlaney
I recently looked a several subs for my system and was amazed at the  GoldenEar ForceField 3  which I ended up adding to my system and contemplating adding another.  1000 watts of clean, deep and sharp bass.  I highly recommend new or used.  You will not be disappointed. 
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BK Electronics makes the best consumer subwoofers in the world, as far as I’m concerned. Available to U.S. factory direct from UK. Exceptional prices too. This is the original OEM company which manufactured the ST line for REL and made them famous worldwide.

Take particular note of the Monolith Plus. It uses the Danley designed and Eminence built LAB12 woofer. And 500 watt MOSFET amp. LAB12 is used exclusively in Danley speakers and IMAX theaters and is considered by many to be the best subwoofer in the world.

BK is incredible value and has excellent customer service.