I wrote a little page about sound proofing the Mini on my website
http://xp.solidhelium.com/Mini/soundproofing.htm

It is by no means a definite guide on sound proofing the car, its just something I've tried that works. Infact I'm sure this is NOT the best material for sound proofing a car. If you have any additional information on what materials to use, (preferrably something cheap, thin, light, and moldable) by all means post it!

side note for people that won't read the whole article but post when they see the picture: This material is designed to repel water, and specially designed not to grow mold. Also, dynamat type materials are mainly used for damping vibrations, not absorbing/blocking out sound, which is what my sound proofing goal is.

 

huh...interesting.

Does that material get pushed onto the glass when you put
the panel back on? not sure if it would matter if it did or not...
auto inside window cleaning pad.

 

you know, it has to be a water proof material in there, the insides of the doors get soaked when it rains.

Dynamat or the roofing tar with a foil backing equivalent is the best way to go. from the looks of it, you will have mold growing in no time....

 

even the inside side? (i was thinking that too...)

 

yep, on the inside of the door, it gets a filmy wetness all over it. i'm still worried about my speakers, i'm looking into foam baffles to protect them.

i had to use a heat gun to try the door off before i put my dynamat in.

 

Nope, this material I used is specifically designed to repel spills and mold growth (it is used under hardwood floors so..)

Also it does NOT even touch the glass slightly, theres enough room for another layer of it actually.

Dynamat or roofing tar foil are only good for damping vibrations, not really good for absorbing/blocking out sounds.

 

well, does it actually deaden road noise? it doesnt seem something like that would deaden the noise much, its just like a padding.

I'm going to get a roofing grade tar with a foil backing for my car, a little goes a long way. 4 square feet will do 2 doors. 8 sqft and you could do the doors, the 1/4 panels inside and the boot lid.

 

Just read my website for the whole article

In 2 words: It works

 

Josh Wardell had a speaker failure due to moisture, and has a solution:
http://www.jwardell.com/mini/2005/09...your-speakers/

 

yep, those look like the foam baffles Crutchfield sells.

I still am unsure of the padding, i think the car has enought padding to prevent any road noise (which i like to hear anyways) seeing as the carpeting is like 2 inches thick.

 

The main thing is that I'm covering places where there are nothing normally (inside doors, under rear seat, beside rear seats, boot lid.

My mom, which didn't know I put in extra insulation, commented that the car "seems quieter today" after I did it. Its no Lexus, but it certainly works. I'm sure there are stuff that works better, but dynamat type definitely won't help road noise as much as this (as I've tried it on a previous car)

 

besides the rear seats already has sound proofing built into the panels themselves.

it might be a nice addition if you dont like road noise, but right now, i just wanna get rid of the rattles cause by my stereo. it might be worth a try and see what the effects of it are...

 

Yeah, no harm in adding more, the total weight added to the car cannot be more than 15lbs, not good for performance, but perhaps not a very big deal for most people.

Definitely go for dynamat type material if you have rattles, might as well cover the whole car and tell me what the difference is :smile:

 

i get so much road noise from my performance tires that i would have to do that on the fender liners... or turn up the stereo a little.

 

no kidding man, id just do under the rear seats to get rid of it! people keep telling me my car sounds like a truck with boggers!

 

You know, I looked into adding some of these to the fender liner but there isn't much space there, hehe. I think it would make a pretty big impact if you can put in some industrial quality sound blocking rubber mat there.

 

90% of the noise in a car is transmitted to the interior by vibration of the sheet metal, thus, dynamat-type material works very well to keep sound from entering the car at all.

For half-price dynamat-type sound-deadening material, try McMaster-Carr, at http://www.mcmaster.com/

If you want to also absorb sound after it gets in, try using heavy carpets floor mats, like these http://www.lloydmats.com/heavyweight_features2.htm

 

Which damper material did you buy? I found these on the site.

Adhesive-Back Damping Sheets
Just peel back the pressure-sensitive adhesive backing to bond these sheets to surfaces such as ducts, pipes, and enclosures to control vibration.
The polymeric mastic sheet is asphalt-based; all others are made of super-flexible, thermoplastic PVC. Chemical-resistant thermoplastic sheets are USDA compliant for incidental food contact. Sheet Temperature lbs./ Thick. Size DLF Range sq. ft. Color Each
3-Ply Aluminum 0.015" 24" x 48" 0.21 -65° to +250° F 0.4 Silver 9709T25 $20.16 Flame Resistant Aluminum Face 0.041" 27" x 48" 0.14 0° to +160° F 0.4 Silver 9709T24 63.86 Viscoelastic Asphalt 0.050" 24" x 54" 0.13 -20° to +180° F 0.4 Black 9709T26 23.86 Polymeric Mastic 0.070" 32" x 54" 0.10 -30° to +300° F 0.7 Black 9709T19 14.62 Chemical-Resistant Thermoplastic 0.125" 48" x 54" 0.32 -32° to +125° F 1.1 Blue 9709T27 160.90

 

I bought some of each of the three materials sold by McMaster-Carr and used all three, but there's only one I would buy from them again. They sell three suitable varieties:

- .050" viscoelastic mastic - not as sticky as real dynamat, and fairly stiff. Tough to form into the dents and shapes of frame members like under the rear seats, but at least it stays put when you get it formed.

- .070 polymeric mastic - also not as sticky as dynamat, and too elastic. It damps well, but the adhesive isn't strong enough to keep the rubber from trying to return to flatness across smaller indentations. Also, no type of damping sheet I tried would stick very well to the surface of this stuff for a second layer. It took washing the surface with acetone to clean off the surface glaze to where I could put a second layer on top of it.

- .040 flame-resistant with aluminum layer. This is the one that is good stuff, but it's more costly than the other two products. The adhesive is very sticky, like dynamat, and the aluminum layer is much thicker. You could cut yourself on an edge. The thicker alum. makes it tough to press it into deep indentations, but it's quite good for a single layer on fairly flat surfaces, like the sheet-metal inside of the doors.

The low-cost product I wound up most pleased with overall was from Home Depot. Look in the rain gutter department, for a product that is intended to patch leaky gutters. It's probably only .030, but has an alum. foil layer, is very sticky, and is much like thin dynamat. It is a mastic, so it is easy to push into the dents, and the alum. should help with damping. It's cheap enough to use two layers - my local HD sells a 6"x25' roll (12.5 sq. ft.) for $16.

Just for grins, I experimented this weekend wth damping the front floorpan without removing the seats or carpets - see https://www.northamericanmotoring.co...ad.php?t=59536

 

The cheesy plastic "firewall" that separates the cowl intake area from the engine compartment is yet another effective spot for a square foot of damping material.

I used several pieces of generic black dynamat about the size of my hand, placed on the passenger-compartment surface of these plastic intake shields, and one piece on the piece of plastic in back of the brake lines inside the cowl compartment - just forward of the glove box.

I was surprised at how much high-frequency engine and road noise can be blocked by deadening these plastic compartments just a bit.

 

You guys should'a bought Cadillac's!

 

Having driven OldRick's car over the weekend (after his dynamat exercise was finished), through some forested and very spirited turns, and over some rough Oregon backcountry twisties....I came away impressed.

The dynamat, while adding nominal sprung weight, made a huge difference.

The car sounded so solid and taught. The rear seats were folded down, and it sounded far better than my car with them up. At WOT, I was able to carry on a conversation without yelling, yet I didn't feel disconnected from the car at all.

I was sold on it, for him. It is not necessarily what I would do, but it sure made an audible and tangible difference.

 

onasled - funny you should mention Cadillac, as that used to be synonymous with quality.

One of the effects of removing resonances and noise from the Mini is that the perceived build quality is significantly improved - the car doesn't rattle, and you can have a conversation with your passenger without raising your voice.

Don't worry, though, there is still enough joyful noise to let you know that the car is sporty - mine is still noisier than a BMW 3-series, but the overall effect is now much more like a BMW than a cheap econo-box.

 

OldRick, can you list what you've done? I know that you've done some less common things like foam injection into the frame.

 

Re. sound control, much of what I've done I learned from others on NAM, but to list the stuff I've tried that helped:

- Really thick carpet floor mats - the thickest and heaviest available - http://www.lloydmats.com/heavyweight_features2.htm In addition to the floor and boot, I also got their piece that covers the rear seat backs when folded, because I carry a stuff a lot more often than people back there.

- A couple of thicknesses of thick carpet scraps inside the taillight area, and the inside surface of the boot cubby hatch covers. Kills most of the exhaust noise.

- Generic dynamat inside door sheet metal, under rear seat, and boot floor. About 35 sq. ft total.

- Foamed the frame members under the car (not a biggie).

- Hand-size pieces of generic dynamat on top of the airbox, on the plastic "firewall", and the "eyes" of the front wheel wells. Reduces high frequency engine noise, like valve noise and supercharger whine.

- A 7"x16" piece of dynamat replacing the black plastic piece inside the hood scoop. More engine noise and road-roar reduction.

- Carpet scraps on the bottom of the rear seat stashes on the side walls. (I had some carpet left over)

- Steel diamond-plate under the front floor mats. This is because I get a bit more than usual engine throb at idle, due to having urethane lower-rear "torque control" engine mount from Mini-Madness. Probably not worth it otherwise.

That's about it. k-huevo and Josh Wardell have done some nice write-ups on the topic. Search for dynamat, and you will find a lot of information and how-to's.