Qts is a driver Thiele/Small (accepted) parameter that indicates how stiff/compliant the driver is.Yes the Abby is an excellent example of a TQWP. Jazz, folk, and chamber music are examples of good uses for TQWP. OTOH can a speaker really be "good" if its only good for certain types of music? Workmanship on the Abby is beyond reproach, but it's expensive and is a hit or miss on the significant other acceptance issue. Omega Grande 6 (bass reflex) does as well in a very well made large standmount for about half the money. Bob Brines' FT-1600 (floorstanding mass loaded transmission line) does better/deeper bass for about half the price.
, and a good one for jazz