I bought these drivers on November, 2002... did I just set a record for the longest time in building a subwoofer? :b - What I tried to do: * Build a decent enough subwoofer with parts available in México City. That means no Adire, no Parts Express, no... well, you get the idea. - The specs: * Driver: Cerwin-Vega! HED-12 DVC subwoofer drivers. * Wired in series, for an 8 ohm load. * http://www.cerwin-vega.com/products/...dio/index.html - The boxes: * Two 40 x 55 x 80 cms. boxes, heavily braced with 2 crossmembers, 1" MDF, countersunk screwed and glued, 118L total net volume (braces and PVC pipes included). * Tuned to (approximately) 19 Hz using 4" PVC pipes. * Twin audio inputs per box (one per voice coil). * Used 1/2 lb of polyfill per 1 cu. ft. * Semi-gloss black finish, silver legs. * Weight: around 100-110 lbs. - The amp: * Harman / Kardon integrated amplifier (100W RMS per channel into 8 ohms). * PE 300-794 amp running at 272W RMS into 4 ohms (the two drivers are running in parallel). - The simulation: * According to WinISD: * Transfer function magnitude: -6dB @ 20 Hz, slope starting at 60 Hz. * Group delay: 20mseconds @ 20 Hz * Cone excursion: 22mm. max at 100W per driver, 30 Hz. - The pics: * Box with stuffing, driver not installed, caulk in place. 15 cms. tall feet. * Box ready to accept driver installation: * Driver in place, all ready to go!: * Twin boxes in place, minimonitors, electronic equipment and TV: - The sound: I substituted a sealed C-V sub (which I made using the same drivers these subs have) for the twin vented subs (Hertz-1's? I like the name!). I absolutely loved the sealed sub - it had a very nice sonic signature to it. But it rattled at high volume (mainly because I used an old particleboard box for it). I intended these subs to go into a much larger room, but things changed... still, I thought it'd be an interesting thing to build. Well, I should have known better. For this particular application the sealed sub is a better option.... yep. It is. Why? Because the whole room rattles with the sound of these things!. Bear in mind the room is made of mortar, bricks and concrete... but the subs have so much lower energy they make every window, door and closet rattle. The TV itself rattles! (not a good thing, I assume). Whenever I try to "test" the subs, the whole room is overwhelmed by vibration. The subs themselves at lower volume sound incredible. They have a very dry signature to them. There's zero overhang (when compared to a Velodyne sub I own). I guess they need to be broken in - I could hear some rattles inside the box as every screw began to seat in in their positions. But the sonic character is quite nice - it goes down *deep* and the driver themselves never seemed to bottom out during testing. The sound is close to my Tempest sub - very close, in fact! In this particular room, I guess there's so much bass reinforcement these babies sound even lower and deeper than my AA Tempest (which is in a much larger room). The twin design helps a lot in never even making the drivers breathe hard - although when I tested the setup with just one subwoofer, I noticed there weren't so many rattles in my room. I guess the 30-20Hz added energy is really making everything move. Another thing. They don't mate well with the little ProMonitor 80 speakers. They have way too much bass and gain! I'm losing a lot of output by running the subs calibrated to the mains. My original plans called for much bigger DefTech BP-8 bipolar towers, but I had to scale back on everything. Bottom line - Manuel, buy the HED-12's. They are a *steal* at $60 USD! My whole project (twin boxes) cost around $470 (amp not included), and I can't think of *any* commercial sub for less than $1,500 USD that can even come close... as a matter of fact, I think DIY subs can't be touched by commercial offerings by now. / Edit: added new pics.