They're are plenty of >12" "high end" subs sold at brick and mortar stores. Either sales guys aren't showing you what they have or are pulling your leg.
JL Audio F113
and Gotham G213
use 13'5" drivers.
Revel's new Rythm2
$10k uber-sub uses an 18: driver.
have 18" and 15" drivers, respectively, and their 1812 has a 12" and an 18" driver in one cabinet.
Wilson Thor's Hammer
with dual 15" drivers.
Focal Sub Utopia EM
with a 13.5" driver.
Paradigm Sub 15
has a 15" driver.
KEF's top of the line Reference 209
uses an 18" driver.
JBL Synthesis S15EX
confusingly has "15" in the title but an 18" driver.
Wisdom Audio's top of the line STS
sub uses dual 15" drivers.
Pro Audio Technology (very high end custom install stuff) have their LFC-15sm
, and LFC-21sm
with 15", 18", and 21" drivers, respectively.
Even in the (ultra) high end 2 channel speaker world you see 15" drivers used in full range towers. For example the stunning Rockport Arrakis
have 2 x 15" per tower, and cost a whopping $165k. Plus, they don't sound half bad either. Neither do the Wilson Audio Alexandria XLF
which uses a 13" and a 15" driver in each tower. And the JBL Everest DD66000
also comes packing dual 15" drivers per speaker.
These brands consist some of the very tippity top of the high end, in engineering, cost, and reputation, with up to an almost unlimited budget, and use >12" drivers. If sales guys are giving you some old-wives tales about 15"+ drivers being slow, and high end not using them, ask them why do these brands/engineering houses use them in their highest end offerings?
(*This post intentionally ignored several of the best subs and drivers out there as I was concentrating on just brick and mortar stores and "commercial," pre-built subs. ID vendors such as Seaton, JTR, SVS, Funk, Rythmik, PSA, and Hsu all make great systems with larger than 12" drivers. Additionally DIY options abound with amazing drivers such as the TC LMS-5400 and the RE XXX18D2. No slight was intended to any makers or owners of these and other fine subs, but I had to stop the list somewhere.)