I was going to add this to the sticky but I dont know if it would have been seen by everyone.

To start off with, I drive an RSX now and I'm looking to move over to an RX7 and thats why I've been spending time here, but I feel it necessary to add my opinion on sound deadener, brownbread in particular, as I've done my entire RSX with it.

First off, its not for the faint of heart. I'm pretty capable, and I bet most RX7 owners are too, but don't take the job lightly. Its long and messy, very messy. I removed every panel from my car following my service manual exactly, and broke a few clips and small parts along the way (thats unavoidable, I have to say). I stuffed the inner and outer panels with polyfill pretty tight, then sealed it all down with brownbread, and spray adhered 3/4" sheet foam batting on top. Brownbread is just as good as anthing else and its pretty cheap. But its a bitch to work with. Its like tar, asphalt. I did some things in the winter and that was a pain as the stuff is hard as a rock, and I needed to use a heat gun, and I was working in my cold garage. Cutting that stuff in your car is a pain. I ended up frozen, cracked, cut, and burned.

I continued the car last summer, and it was easier, but the stuff smells like *** and sticks like crazy, its a mess. Then fitting panels back on can be a pain, as you can accidentally cover over holes and stuff.

I put a ~$4000 sound system into my car and felt that a good install was just as important. There is no doubt that the car is much quieter while driving, but the important thing to remember is that there is still noise coming in from outside. The RSX is already a quiet car I have to mention, and there were no rattles. The thing sounded very listenable while driving - but was still not really acceptable for audiophile grade music unless the car was still, with no wind, and engine off (watch the voltmeter).

The added weight of the bread alone wasnt noticeable, but the entire sound system was. Now.. I just wanted to mention this to aid RX7 owners. Because I feel like the RX7 is a precious and rare car, and once brownbread goes in a car - it really never comes out. Not fully at least. The added weight to a sports car like the FD would probably be noticeable. All in all, my car sounded better with the deadener, but only marginal, and wasn't worth the time, effort, money, or weight. I would not do it again unless it was in a truck with SPL goals (the deadener made it much quieter on the outside). On my upcoming FD, I won't dare abuse my car with that tarry crap. Thank you.

 

~20 lbs of weight isn't going to be noticable. Thanks for the heads up tho.

 

Yeah if you used it in small amounts, like around just the speakers or just the doors, the weight and effort is negligable - but so is the return. I couldn't tell much of a difference except for slightly less localized hum outside the doors. If you wanna do it right you need to do the entire car.

I bought two rolls from b-quiet.com. 70sq ft each. The total weight was only 58 lbs for all of that, plus whatever my polyfill and foam were (so lets say 60). Considering some of the great lengths people go to to put their cars on a diet, I don't think that is worth its weight.

 

Choser: appreciate the info

i was thinking of using those undercoating spray... have anyone tried this?? and then put some sound deadening sheets to cover all of the door. Would it make a difference?

 

wow I wouldn't have thought it would have been 60lbs for all of that, thus why I guessed 20lbs. I'm sure there are other light weight alternatives out there for adding sound deadening. Albeit not as effective, but still somewhat effective none the less.

 

Sound deadening works good...sometimes...but I dont know if its worth the time and effort...thanks for the info btw

 

Here is the answer. Don't be cheap. Buy Dynamat Extreme. It is VERY easy to install. Sticky enough to stick the first time with no heating but it doesn't get all over you and smell like that Brownbead stuff. I bought a bulk pack (9 sheets) which weighs 20 lbs. I applied around 3 sheets to the driver door and it seems like it will make a huge difference. The doors sound very solid when you knock on them and not hollow as they did before. I will be doing the passenger door probably tomorrow so I will have used 6 sheets which equals around 13 lbs. Anyways, I'll be sure to start a new thread about the whole system once it's complete in a few days...

 

All the reviews I've read show that the only thing that really matters is the mass of the item. They are all virtually the same material too. You're just lowering the resonant frequency of the panels.

I doubt that Dynamat Extreme is any better or even different. Its just more expensive. 140sq. ft. of Brownbread costs 300 bucks. Around $950 for the Dynamat Extreme.... eek. Small simple and flat installs are simple, but when you line every square inch of your gutted interior with deadener, and have to cut the things precicely, its just a PITA. And it *will* start to smell come summer time and a hot day.

 

i used the brown bread in my car. i only used 20lbs. (one roll) when ya take the plastic out you can tell mazda was really all about weight savings ... i had almost no sound deadening under my plastics. i was able to do one layer in the whole car and on each door, the hatch, roof, floor. i live in FLA and did it on a warm day so it was easy to work with i never needed a heat gun. i have never done this before and it took me a weekend, i'd say about 10 hours from start to back together.. (but i also ran all the wires for a future stereo upgrade) It made a big diff in road noise coming from the rear and seemed to lower the over all noise that normally finds its way into the car... i have to say the doors even sound better when ya close them (a much more solid sound/ feel) of course they are a bit heavier so that would make since. i'd hate to pay for the "brand name stuff" that does the same thing. i feel the results were worth the effort of sounds deadening and i would do it again. just make sure you re-open the holes in the low parts of the car they are to drain any rain water that might get in! i missed one in the spare tire well and after a nice florida rain storm i could have been the first RX-7 with a hot tub! A pen knife took care of my pesky hot tub problem.

 

I used the FatMat stuff and it worked great. I just layed the material in front of my 500 wt work light and it was very flexable. One roll was more then enoug for the entire car, I leftovers now. Worth the envestment and only around 30lbs max. And about 25db quieter.

John

 

I have used Q-pads, industrial sound deadener spray on from McMaster corp., Dynamat, etc etc.

its definately worthwhile, and there are brands that are not messy.

One of the best and friendliest deadener companies is Second Skin Audio

www.secondskinaudio.com

they have a good selestion of different types of deadening, and are very knowlegeable about their products and application.

 

as far as dynamats claim to transform mechanical energy (vibrations) into heat i may not be a believer, but
it is not as messy.
ive use
dynamat
roadkill
brownbread
and others but dynamat is the best to work with.
the brown bread sucked because the tar releases and get all over everything