[wushuliu]

Originally $3400 and $4500/pr respectively. Now $800 and $1200/pr. Audioholics did a comprehensive review of the 15 and it's *very* impressive.
These are 3-way designs with offset tweeters plus passive woofers. Bass down to 40hz for the 15s, even lower for the 17s. Frequency response +/- 1.5db(!). Plus an aluminum baffle!

The Demand line was an attempt by DefTech to branch into more conventional speakers as opposed to their well known bipolar designs. Unfortunately it looks like the Demand line didn't get the necessary traction and has been discontinued.

I consider these enough of a steal that I just bought a set myself.

EDIT: Just unpacked the first speaker and the online photos don't do justice to the quality of the finish and feel. These are gorgeous.

https://www.accessories4less.com/make-a-store/item/deftechdemandd15blk/definitive-technology-demand-d15-pair-5.25-3-way-floor-standing-speakers-black/1.html

https://www.audioholics.com/tower-speaker-reviews/def-tech-demand-d15