Sound Deadening-Why alum. over large holes?

[tracyrick 10+ year member]

K, question for anyone that has done this before. Please see below quote.

Why won't the mat cover the large holes? Why do you have to use aluminum? Also, any alternatives besides alumunium if I can't find a good source?

http://www.sounddeadenershowdown.com/howto/

"Laying mat over the larger holes will probably not be sufficient. I like to use aluminum flashing from a roofing supply or hardware store. I just bough a roll, 14 inches wide by 10 feet long for $8.00. It is thin enough to cut with tin snips or heavy shears, but rigid enough to do the job."

Click to read more...

 

[mrwigglezdj 10+ year member]

my guess without looking further into details , would be because the adhesive on the deadner isnt made to support the weight without the whole peice being attacted to some kind of surface, and the rolled flashing will give the deadner a foundation to adhere to instead of being free air'd in the non metal or whatnot areas...

in other words the deadner will sagg and if there is nothing to pin it in place will fall off, or flap around from the bass pressure and fall off

 

[JimJ 5,000+ posts]

I used Lexan panels that I cut to fit...the idea is to provide a solid backing so the entire door will function as one large enclosure.

 

[CBFryman2 5,000+ posts]

Because mat is flexiable so it will act like a passive radiator. You only have to use that aluminum if you are sealing your doors. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[klepto 10+ year member]

You dont need to use aluminim, its what i used tho. Pretty easy to work with if you have some sheet metal cutters. Sound deadning mat isnt strong or rigid enough to cover the big holes. You need something with some structural integrity.

 

[CBFryman2 5,000+ posts]

I used Lexan panels that I cut to fit...the idea is to provide a solid backing so the entire door will function as one large enclosure.

Painted scrap plywood FTW for me. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[klepto 10+ year member]

Because mat is flexiable so it will act like a passive radiator. You only have to use that aluminum if you are sealing your doors. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Well you can never 100% seal your doors. Something about that hole in the top where the window comes out leads me to believe this. But, sealing the major door holes do help a lot.

 

[tracyrick 10+ year member]

Got it now! Thanks for the tips. Now I have to find some aluminum or something else light but rigid.

 

[klepto 10+ year member]

Go to Home depot, they sell sheet metal sheets.