I investigated the FW stuff, and it looks like awesome furniture, but no dealers means you can't listen first or even check the real build quality,
You're correct. You're purchasing a sub that you can't listen to first, or even check the real build quality. If listening first if your determinant of a purchase then that's your call, but there's plenty of documented FW builds online that show you the build quality involved:
http://www.avsforum.com/avs-vb/showthread.php?t=1354003&page=2
http://www.avsforum.com/avs-vb/showthread.php?t=1313021
http://www.avsforum.com/avs-vb/showthread.php?t=1283555
so those prices seem to have a lot of assumed risk built into them.
On the contrary, those prices have huge savings associated with them. if this sub were sold in B&M by the typical brands, you'd be looking at over 10k. I was looking at the price for the JL Audio Gotham = 13k and couldn't help laugh my *** off.
Not only would one LMS5400 based sub run with a gotham (beat it?), but for that much money you can get four, which has much better in room frequency response and much more headroom.
Subwoofer specs are often too good to be true, so I'm not so sure I'd spend that much sight unseen or sound unheard.
Luckily not one person here could care a smidgen about subwoofer "specs". We're all about actual measured performance andd the LMS5400 is tried and tested:
DIY TC Sounds LMS-5400 18" sealed 100L - Home Theater Forum and Systems - HomeTheaterShack.com
If anything, I'd say the paradigm and velodyne are the real gamble. You really think your ears are a good SPL/extension/distortion/group delay/room gain/ringing measurement tool? You really think an audition room and audition setup are indicative of YOUR room and a true PROPER setup that isn't designed to sell a subwoofer?
It seems people come here asking for advice pretty often and then buy mediocre subs because they can get it at a dealer (sometimes at "discount"
) or because they can hear it. If you fit the bill, then go ahead and take your pick of overpriced or mediocrity (and sometimes both).
At some point you really have to consider all the research about low frequency reproduction that tells us how to maximize the SQ of our systems. Given the choice between a single Velodyne DD18+ at $5500 and a HSU Quad Drive at $4000 i`d consider it a no-brainer as to which option will sound better; not even factoring cost in.
Some of those 18" FW box sizes seem pretty small for non-servo designs.
Servo has nothing to do with box size. What servo does is correct non linearities and isn't without its tradeoffs. Yes a driver will be less linear in a higher qtc box where variations caused by voice coil heating are more signfiicant to its frequency response and could use correction... but an LMS5400 sealed in 90L actually has a (low) QTC = .63 and is going to be more linear than even servo drivers can hope for, thanks to its variable density voice coil which deals with issues of linearity ::at the magnetic gap::, rather than ::at the amplifier::. I showed the measurements earlier of what it can do, and bear in mind those are continuous measurements @ 2m. - at 1M and PEAK (which is basically a more standardized measurement) you can add 9db to each of those values. I'm willing to bet those Paradigm/Velodyne boxes are qtc = 1.0 type deals which yes servo will correct but not efficiently.
And the TC Sounds driver with the cloth-roll suspension... nice 1950s cone technology.
Clearly you`re an expert on driver design.
The LMS5100 (not the 5400) is a pro audio woofer designed to not only dig pretty deep for a high sensitivity driver but also reach high in frequency. for a driver to sound its best you want to take surround resonances at midrange frequencies away. Foam/Rubber surrounds are fantastic for a long throw subwoofer but they do have arguably audible resonances higher up in frequency when used as midwoofers.
Different applications have different methodologies used. Unless you know what you`re talking about its best to keep such comments to yourself. Likewise with cone material, whose effect at low frequencies is identically pistonic, and far more relavant in terms of determining driver fs / sensitivity