I've been doing some digging to find out more about the sub manufacturers and how they go about building their subs.
The curved cabinets of the Funk subs look great but the prices are too high. It seems Funk Audio is a one (or two) man operation and their subs are built from the ground up with their own cabinets, drivers, and amps. However, for the money I'd feel more comfortable going with a more established brick-and-mortar or ID brand.
I contacted Deep Sea Sound to inquire about the cabinet build and driver used in the Mariana 18S Sub. I wanted to find out if they were building the cabinets and drivers themselves. I got the following reply from David Gage: "The 18" subwoofer driver is the HST-18 D1 built by Stereo Integrity near Charlotte North Carolina. The SP1-4000 amp with 4,000 watts of continuous power is built in Santa Ana, California. We build the enclosures ourselves in Knoxville, TN and then put everything together and test thoroughly before shipping out." It appears DSS is using quality components from well-known manufacturers. DSS is a new company and I would lean toward Seaton, Klipsch, etc.
I sent an email to SVS to find out where their subs are made and I got the following response from customer service: "SVS products are designed and engineered in the USA, and manufactured in Asia to SVS specifications, under direct SVS supervision. All SVS products shipped from our OH facility undergo a comprehensive QC and audio check by our factory technicians before being shipped to the customer." SVS subs might not be the best but their customer service is supposed to be quite good.
The Seaton SubMersive cabinets are CNC'd by WW Speaker Cabinets and I was not able to find info on the drivers and amps. Does anyone know if the drivers and amps are made by Seaton or purchased elsewhere? I don't recall seeing a photo of the driver used in the SubMersive HP+ or F18+.
JTR uses Baltic Birch construction in their Captivator S1 and again I was not able to find info on the origins of the drivers and amps.
I've cut the sub choices down to the THX Ultra2 Subs, SubMersive HP+, SubMersive F18+, JTR Captivator S1, and SVS SB13-Ultra. On a side note, it's always interesting to read about comparisons between these subs and the JL Audio Fathom, Velodyne DD+, and top-of-the-line Paradigm subs.