Originally posted by: Viper GTS
Total cost for each sub (unpowered) is around $400. That includes the driver, tube, wood, port kits, & all miscellaneous components. I had to buy 12' of Sonotube ($105), only ~3' of which got used for each sub. I'll have $50 worth of Sonotube left over. If you were to build just one the cost would be slightly higher, maybe $500.
You can spend anywhere from $100+ on an amp. The drivers are rated at up to 750W, but they can easily be driven with only 250W or even less. I spent $280 on ebay for a used RMX860 with a SKB case because I want to migrate to pro equipment. A simple 250W plate amp will power a Tempest fine, though you would need to build an external enclosure for it or build it into the tube wall (not recommended). My QSC will power both subs if I end up stuck with both (I say stuck like that's a bad thing...).
Labor is the truly expensive part, this took me almost a month to build @ several weekday evenings + a large portion of weekend time. I always had at least two people working on it (me & my brother) and frequently a third.
Each endcap is 5+ layers, two of which are 1" MDF. The bottom endcap is 3" thick, & each cap weighs probably 40 lbs on their own. Each received two layers of automotive primer, 4 layers of silver paint, & four layers of clearcoat.
More pictures
When I get home tonight I'll zip up the CAD files & upload the rest of my pictures, I have quite a few more that I haven't put up yet.
Viper GTS