easiest way to seal off a trunk wall

[keep_hope_alive Premium Member]

the gain you get by opening the trunk is easily explained. you eliminate destructive interference. the wave hits that trunk and bounces back some time later, out of phase with the front wave. that is cancellation. it's also lost energy and pressure. if you gain dB's opening doors, you're not loud enough. at that point, you just minimize interference and create a bandpass enclosure made from the cab. this is a super simplified version of what is actually happening. physics explains everything.

you want to reach the point where you are pressurizing the cabin and any leak is lost pressure. i have no idea what that turning point is, but i assume it's unique to each vehicle and probably a function of volume.

most of us are just battling phase interference. your goal should be a fully coherent wave combination with constructive interference at the mic location.

CAT MAN was looking at my build wondering if he also wanted to make a rectangular frame that fully reinforced the trunk and gave him a universal platform to bolt boxes to. oddly enough, i made it removable so i could experiment with subs and boxes. turns out i was happy off the bat. but new subs will come soon enough, and as long as the box fits the frame, it will seal perfectly.

 

[CAT MAN 5,000+ posts]

the gain you get by opening the trunk is easily explained. you eliminate destructive interference. the wave hits that trunk and bounces back some time later, out of phase with the front wave. that is cancellation. it's also lost energy and pressure. if you gain dB's opening doors, you're not loud enough. at that point, you just minimize interference and create a bandpass enclosure made from the cab. this is a super simplified version of what is actually happening. physics explains everything.
you want to reach the point where you are pressurizing the cabin and any leak is lost pressure. i have no idea what that turning point is, but i assume it's unique to each vehicle and probably a function of volume.

most of us are just battling phase interference. your goal should be a fully coherent wave combination with constructive interference at the mic location.

CAT MAN was looking at my build wondering if he also wanted to make a rectangular frame that fully reinforced the trunk and gave him a universal platform to bolt boxes to. oddly enough, i made it removable so i could experiment with subs and boxes. turns out i was happy off the bat. but new subs will come soon enough, and as long as the box fits the frame, it will seal perfectly.

idk what we would do without guys like you

 

[xSPLoder 10+ year member]

every person I see in trunk class uses gorilla tape and cut mdf to frame around the box. just throwing it out there. they also already make pre made foam boards at home depot and lowes you can look at too

 

[THATpurpleKUSH 5,000+ posts]

my .02 on this- make a u shaped frame that will be placed upside and goes around the box to cover the gaps on the sides and top. Make a template out of cardboard first to test fit. Then when you are ready, transfer it to your wood of choice. To seal it use screws and silicone caulk where possible. 3m 5200 is great stuff. Then apply some of this stuff all around the seams: 324A 2-1/2 in. x 180 ft. Cold Weather Foil Tape-3240024500 at The Home Depot

 

[madcad95 10+ year member]

I pulled the carpet out the trunk and threw it in the garage and broke out the expanding foam then resined over it and painted it and wala and if I feel like going back to stock someday then that's when the work will start tearing it out and putting the carpet back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[CAT MAN 5,000+ posts]

every person I see in trunk class uses gorilla tape and cut mdf to frame around the box. just throwing it out there. they also already make pre made foam boards at home depot and lowes you can look at too

yeah i was going to do peel and seal instead of tape. not for deadining purposes but because the seal we have in my lowes is sticky as *****

my .02 on this- make a u shaped frame that will be placed upside and goes around the box to cover the gaps on the sides and top. Make a template out of cardboard first to test fit. Then when you are ready, transfer it to your wood of choice. To seal it use screws and silicone caulk where possible. 3m 5200 is great stuff. Then apply some of this stuff all around the seams: 324A 2-1/2 in. x 180 ft. Cold Weather Foil Tape-3240024500 at The Home Depot

love that tape

I pulled the carpet out the trunk and threw it in the garage and broke out the expanding foam then resined over it and painted it and wala and if I feel like going back to stock someday then that's when the work will start tearing it out and putting the carpet back //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

**** you poor people and your spray foam

 

[xSPLoder 10+ year member]

**** you poor people and your spray foam

rofl

 

[keep_hope_alive Premium Member]

in the amount of time you've spent on the forum talking about how to do it, you could have made a nice, thick wood frame perfectly cut and sealed around the box. that's the only solution i would entertain. if your goal is deebee's then you want something rigid. a 28 foot wavelength (40Hz) isn't stopped by cardboard. flex is lost dB's

just sayin... "easy" is relative.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[bgowdy 5,000+ posts]

the gain you get by opening the trunk is easily explained. you eliminate destructive interference. the wave hits that trunk and bounces back some time later, out of phase with the front wave. that is cancellation. it's also lost energy and pressure. if you gain dB's opening doors, you're not loud enough. at that point, you just minimize interference and create a bandpass enclosure made from the cab. this is a super simplified version of what is actually happening. physics explains everything.
you want to reach the point where you are pressurizing the cabin and any leak is lost pressure. i have no idea what that turning point is, but i assume it's unique to each vehicle and probably a function of volume.

most of us are just battling phase interference. your goal should be a fully coherent wave combination with constructive interference at the mic location.

CAT MAN was looking at my build wondering if he also wanted to make a rectangular frame that fully reinforced the trunk and gave him a universal platform to bolt boxes to. oddly enough, i made it removable so i could experiment with subs and boxes. turns out i was happy off the bat. but new subs will come soon enough, and as long as the box fits the frame, it will seal perfectly.

lol that set upi had wasnt that loud... its was about a 144 @ best lol

 

[keep_hope_alive Premium Member]

lol that set upi had wasnt that loud... its was about a 144 @ best lol

that's the nice thing about the class structure within competition. most of us will be in the phase interference range. placement and orientation are the most important aspects of the system. naturally, flex and other losses take their toll too. the vehicle will end up the limiting factor.

IMO - newer cars are too flimsy for SPL. if you want an SPL vehicle, look for something like a 1940's armored truck

 

[RangerDangerV2 5,000+ posts]

if you put down n duct tape and then spray foam over the duct tape no carpet will be ruined.

 

[keep_hope_alive Premium Member]

Armored Truck Inventory

i've always said that if i ever get into SPL, the vehicle will either be from the 1940's (when steel was hammer-proof) or a vehicle built for strength.

like this:

http://www.cardomain.com/ride/2925230/1992-gmc-topkick

i agree you can tape the entire interior off and use spray foam and probably not ruin anything. but why limit yourself? just make it out of wood and call it a day. make cardboard templates then in a few minutes with a jig saw you're set.

 

[bgowdy 5,000+ posts]

that's the nice thing about the class structure within competition. most of us will be in the phase interference range. placement and orientation are the most important aspects of the system. naturally, flex and other losses take their toll too. the vehicle will end up the limiting factor.
IMO - newer cars are too flimsy for SPL. if you want an SPL vehicle, look for something like a 1940's armored truck

yea... i like my blazer tho, i really dont get much flex from it with the 52hz freq i been competing with. with this box being tuned to 32 - 35hz i get flex in my roof now lol. but my box right now sits all the way back at this point. im going to be moving it forward about 1 1/2 to 2 feet when im ready to build the wall around it the should take care of some flex. the roof only flexs over top of were the hatch area is.

 

[RangerDangerV2 5,000+ posts]

Armored Truck Inventory
i've always said that if i ever get into SPL, the vehicle will either be from the 1940's (when steel was hammer-proof) or a vehicle built for strength.

like this:

http://www.cardomain.com/ride/2925230/1992-gmc-topkick

i agree you can tape the entire interior off and use spray foam and probably not ruin anything. but why limit yourself? just make it out of wood and call it a day. make cardboard templates then in a few minutes with a jig saw you're set.

passenger vans with concrete errwhere are the standard for teh burpz.

 

[CAT MAN 5,000+ posts]

in the amount of time you've spent on the forum talking about how to do it, you could have made a nice, thick wood frame perfectly cut and sealed around the box. that's the only solution i would entertain. if your goal is deebee's then you want something rigid. a 28 foot wavelength (40Hz) isn't stopped by cardboard. flex is lost dB's
just sayin... "easy" is relative.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

yeah i realize this but you guys also missed something yesterday. moms car blew up so im stuck taking her to work. ill get on it once we drop a new motor in that tempo. **** car is getting on my nerves. it ran for a whole week after i fixed it LOL