The '10 grand tin can' as we all know, earns its name when it comes to road noise and every other type of noise that could exist in a car - anyone who's stripped the trunk of carpet and plastic knows you can see outside from inside where you really aught not to lol
So while I figure out the mounting of the diffuser, I'm also getting started on phase 3 of sound proofing the car.
Phase one - strip the interior and line the floor with (not) dynamat (used "noico"), pictures to follow.
Phase two - bridging the gaps in the trunk (wheel well to fender... damn thing's a drum skin) with "reflectix" - a thermal barrier for duct work that just so happens to be a great sound absorber (unpoppable high grade bubble wrap lined on both sides with foil)
Phase three - I'm going to fabricate some VB-3 from Cascade Audio. Normally the stuff is $9.80ish per square foot... I'll be laminating aluminum foil in place of the lead sheet they use since it's density changes, not density itself, that causes these materials to function. The foam I'll be using is Volara since it's rated for a 54 decibel drop at 1/2" thick. Since I can get 250 square feet of foam for $70 (+shipping... which'll be another 50ish because it's so heavy). Halved since it's the bread of the sandwich puts it at 125 sq-ft.
250ish square feet of heavy duty aluminum foil is ~$6, assuming I use 10 layers to reach somewhere near 1/64th thick, that's ~25sq-ft per roll, 5 rolls to do 125 = $30... + spray adhesive... so like, $160ish, to get 125 square feet of VB-3... $1.28 per square foot, instead of $9.80/sq-ft + shipping.
Won't make all 125 though, should be more than enough to load the doors without doing that and then line the inner skins with just the foam.
So that's what I'll use this thread for - progression pics of the VB-3 assembly will come, for now, here's some of the ones I took while installing the butyl rubber sheets.
rear cover removal
Pulling the headliner not all the way off
Mind the air bags
after feeding in a sheet, smoothed over scrapper acts as the 'roller'