Yea there is one little problem with that, it doesn't work, lol.
To be honest, competitors that put way too much thought into the science behind waves and such don't seem to hit as high as they want on the meter. I've talked to several over the years that know a lot about the physics behind audio, and always get beat by guys starting out that know nothing about it. Getting louder is all about testing and building different enclosures, testing various sub and amp combo's.
Leave the science of it all to the veteran competitors building Extreme class concrete filled bandpass vehicles and just have some fun and learn it all as you go.
XS Power (2) D3100, D5100, 2 runs of 0/1 ga
a pair of 10" DC level 4's on an Orion 2500d for daily low end _____________________www.NewEnglandSPL.com
2 18" DC XL's and an Atomic 5000.1 - 154.6 so far
Team Elite NESPL
Bought from: CRXBMPN, SPLTucson, f150john, LoudMOFO Sold To: Chris Team ACT, Big Rea$e
The problem with tuning high 50's with the box you had is that the sound isn't coming from the back corner but the front so pathlength to the windsheild is very short then since the box isn't walled off from the back you get a wave bouncing off the back then up front so no telling what that's causing to gain and cancel. That method is quite accurate and I got it from a good source. Not a replacement for testing, but it gives you a ballpark of where you'll have an easier time getting a good peak.
Those coils will go for a while scuffed up, but will probably fail quicker, particularly if you keep rubbing them.
Robot Underground has OEM Audiopulse cones in 12 and 15" (also possibly 12" LA/honeycomb nomex), and OEM coils, and spiders for the 3hp, dunno if he has the LA style frames (assuming yours has the 4 side bolts to hold the top on that's easiest) or you'll have to buy some adapter rings and a TI frame. Will run you some money to recone those with OEM parts... Also there are some 15" TC proto plastic cones on here that look pretty sweet. Would be very unique.