I am a huge fan of HSU and almost pulled the trigger on a pair of HSU TN1220 HO's plus the HSU 500 watt amp, but decided on the lovely HSU VTF-3HO's plus Turbos. I have spoken to Dr. Hsu several times and exchanged email with Pete HSU on several occasions. The VTF-15H is a huge sucess for the company and is on its way to becomming the most popular subwoofer in HSU history.
Kudos to Dr. Hsu! His design chops are second to none. We don't even need to discuss all the consulting work he has done for companies ranging from Outlaw to Dayton, (IIRC).
Bravo to the good Doctor!