DIY sound insulation?

[Jace]

okay guys, i had a pretty big realization recently.
i was driving back from Daylesford on the highway, with my music up to like 20 (out of 30, very loud basically)
and i thought to myself how nice it'd be to be able to hear my music better.
part of this is because i have mismatched tires (between front and back) and get horrible amounts of road noise.

anyway, i've looked into that alluminium sheeting stuff that you stick to the inside of your doors etc.
edit: the brandname is Dynamat
it seems to be really expensive stuff.
it occurred to me that this stuff is basically just alluminium sheeting with a rubbery sort of coating on the back of it and a bit of corrugation through it.
i was thinking that it wouldn't be hard to DIY some of this sheeting.
i'm talking corrugated cardboard, maybe sprayed with rubberised pant (stone chip resistant stuff) and spray adhesive holding it onto alluminium foil layers, or maybe a thicker grade of allu. if it's available.
the alluminium is like an air insulative thing AFAIK, just the same way that sizlation is used in the walls of houses between the brick (or whatever else) and the frame.
anyway, you get the idea.
can someone either lend me some knowhow or burst my bubble, because i feel like i'm really onto something here.

[Jeo]

I sure you could come up with *something*, but really? A door kit of genuine Dynamat can often be found for under $100. That comes with more than enough to do your doors.

There are also cheaper alternative brands around.

[GS]

Im all for DIY and i like your creative thinking. But my first thought was that corrugated cardboard probably isnt a good idea within your door cavity. Water may seep around your window seal and next thing you know you've got a soggy mess in your door.

[GP14]

clark rubber is your friend. I bought some foam about 5mm sheets and contact adhesived it to the inside. Worked a treat. Gave me that extra base on a crappy 6in speaker.

[NMX516]

Part of the benefit of Dynamat is the WEIGHT that it adds. The extra weight on the door skins means that they are less susceptible to drumming. Dynamat is very good stuff, you won't make a better solution for less, otherwise everyone, incl other manufacturers, would be doing the same. A full door kit of Dynamat should cost you less than $130. Jeo must have a good contact to get it for under $100 I think

[doogle]

how about the floor? almost as much noise as the doors must come through there.. unless there is insulation already?

found this link too just searching around the net: http://www.dynamat.com/download/vss/2655_1999_Mazda_Miata.pdf

f thats expensive! and gotta be heavy too...
ebay starts from about $170 posted... where can you get this stuff cheaper Jeo?

a good DIY job would win me over, good luck IH8

[NMX516]

The Dynamat Extreme door kit will do the inner and outer skins of both MX5 doors - on special at the moment for $95 from fhrx studios in Sydney. http://www.fhrxstudios.com.au

[Jace]

more so thinking of covering the floors, doors, parcel shelf, as far up the firewall i can get without removing the dash etc.
yeah the weight is another thing i thought of. i'd probably limit myself to adding 10kgs at an absolute maximum (for performance sakes) but i get where your coming from NMX...
obviously that'd take a hell of a lot of foam and alluminium to hit 10kg!
basically i instantly thought of doing it myself because i've heard of people paying up to $220 for half a door's worth of Dynamat.

after a little bit more research, this stuff doesn't actually seem all that dear.
$200 is a maximum for cost, unless Mr Taxman is especially generous this year, as he was last year!
hmmmm.

[Ando]

I'd like a bit more thud and less clunk when the doors close. The extra weight doesn't worry me though. I've had 4 wheels with their tyres on in the 5 and the extra ballast had no negative effect really. They did try to squash me when I turned left though! I'm definitely going to investigate the Dynamat gear...

[sliq]

My dynamat door kit was about 110 from ryda. They also have a speaker kit but that does close to nothing. The audio guy told me door kit was a must.

[Jace]

fhrx price $450 for a mega pack (probably do two MX5 interiors)
hmmmm. way outta my budget, but it'd have such excellent effect!
hmmm indeed.

[sliq]

http://www.ryda.com.au/ProductDetails.a ... Code=10435


$93!! can't go wrong.

[Garry]

Bitumous type products like Dynamat are only half of the solution. They stop the panel from vibrating by adding extra mass. You also need another medium to absorb the sound waves. Adding some type of acoustic foam product will give you a much better result than using Dynomat alone. Have a look under the carpet of any high end luxury car and apart from the 3 to 5mm layer of bitumous product stuck to the floor you will find anywhere up to 20mm of sound absorbent product under the carpet. Unfortunately a lot of the road noise in an MX5 comes through the vinyl roof. So if you dont have a hardtop or a multi-layer insulated roof you are limited to how much noise reduction you can achieve.

I dynomated my whole car and didn't notice much of a decrease in noise. I did notice that the body sounded much more solid and less tinny over bumps and rough roads. I found another insulation product that I cant remembr the name of but it is similar stuff to the green/pink underfelt stuff Mazda uses under the carpet already except that it has a layer of aluminium foil on one side. It's about 10mm thick.

It was $100 for a roll which was enough to cover the floor but not the rear bulkhead or parcel shelf. This product made a much bigger difference to noise reduction than dynomat alone. Unfortunately I haven't been able to source any more to cover the rear section of the car.