Most accurate sub under 1,500 used


I have been looking at velodyne digital drive series and REL. The room is 12w X 23L X8H. 60% movies and 40% music usage. I am open to other recommendations as well.

Thanks
him
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How much will I gain over the DD12 with the DD15. The 15 will go a bit lower to 15Hz and the 12 is 17HZ. The DD18 is out of my price range.
How much will I gain over the DD12 with the DD15

A lot. If you went with a DD12 you might want two while a DD 15 or DD 18 would probably be enough.
I have a DD-12 in 15 x 20 room with 10 ft ceiling. The volume is set to ~20 comfortably, and I have never maxed out on the volume or bottomed the woofer. You should still get the largest that you could afford, but if it comes to DD-12, I think it could work just fine in your room.