subwoofer recommendations $1000

Want clean bass extension to fill out kestral 2 spkrs. driven by tube amp... mostly jazz and classical tastes. Want musical tight sub as hm thtre use is not needed. k2'S only need help below 40 HZ. used is O.K. too.
See if you can find a used Rel Strata III. Although they are climbing above $1k used now that they are discontinued.

Good luck,
LOOK in to a M&K 2500 new is 1199.00 used ?
REL will go lower but you can save a few buckjs and get a Vandersteen 2WQ one of the great bargains in hifi.Uses unique x-over ste upo where you don't hokk it up line out but combine it with speaker wire taps and itn reacts to full waveform.If you want a Home threatre sub all you need is "boom in the room" the bigger the beter wityh a servo amp doing a beter job.But REL.Vandersteeen,(and above you price point) Martin Logan Descent a set which uses multiple small drivers to equal one big one.To get speed ,pitch accuracy etc your talking $3K and above to move large 15" and 18" drivers in Ariels,Revelss,New Velodyne DD series etc.This means it's fast and lithe enough to be pitch accurate and it's speed allows it to be matched with most demanding speakers including planar's like Maggies (great combo with 1.63.6 with aforementioned) or lectrostatics like Quads where the speed allows pitch accuracy and easiset blending for 2 channel systems.You can get 35hrz +/- 6 db out of Vandersteeen and more depth out of REL out of two into models on used market fpr another $300+/-.
Rel Strata III....they are excellent. Very configurable
to work with a variety of speakers. I've got two.
I have really enjoyed the Revel B12 sub(s) in my own system. They are priced right at $995.00, look great (even if it IS only vinyl over mdf), and have the flexibilty of the graphic eq onboard. Maybe not the deepest sub, but the bass you get will be pitch accurate, tight, and fast.