Long story short, my current exhaust setup is a o/r x and magnapacks on my 04 GT...they are LOUD and also the drone kinda sucks. SO instead of swaping mufflers and whatnot, because I do like the tone of them, I thought about insulating the floor.

My initial idea was to cover the back seat floor (where your feet go) up over the hump and down under the back seat itself. Pretty much just over the mufflers.

Talked to my local car audio guy (who has always steered me straight through helping me with my system) and he said I would have to do the whole floor to do it "right". It makes sense, but I also don't want to do it if I will barely notice a reduction in noise.

That being said. I can figure out HOW much I need and even HOW to do it, BUT in terms of what brand, style (tar-like stuff or the thick foam-like pad) I have no clue.

Wondering if someone could fill me in a little on the basics etc. I know I could add cats to my setup, but doing this ensures a quieter ride all around. ALSO I don't want to add a lot of weight...I do drag the car every once in a GREAT while and plus I just don't want a crap load of weight.

THANKS!!!

 

This is by far the best thread I've seen about sound deading install... http://www.modularfords.com/forums/s...ts-of-pictures.

I can attest that it takes longer than you think to get it done right. If you do the whole car, don't expect to do it all in a day. Hell, one door took me 4-5 hours using Dynamat.

 

First off, sound deadening, as in the butyl adhesive mat with foil on one side does little to reduce transmitted noise. The main use of deadening is to lower the resonant frequency of the panel that you apply it to. Yes it does help some with reducing transmitted noise but not anywhere near what the manufacturers of the stuff have led us to believe. One of my former employees had a 2002 Camaro SS with THREE, yes THREE layers of Dynamat extreme on every piece of sheet metal he could apply the stuff to. He was extremely disappointed with the exhaust drone in his vehicle.

The real way to do it properly is a three step method, and it is extremely heavy. First you would apply Dynamat, Secondskin, SDS, etc. Next you would apply closed cell foam on top of that as a decoupling layer. Finally, you would apply 1 pound per square foot mass loaded, preferably with lead, vinyl on top of the foam, covering as much area as you could.

Even worse... After going through all that, I'd be shocked if you saw a decrease of more than 3 to 6 decibels in road noise. Going further, 3 to 6 decibels in road noise reduction never seems to be the same as gaining 3 to 6 decibels in SPL on a TermLab. Don't know why, but the noise reductions just never struck me as "impressive" for the amount of time, money and effort involved.

There is someone on another forum who is going through that right now and she made sure to take measurements before. Unfortunately, her father passed away recently and she hasn't had time to finish with the after measurements. Here is a link to her thread: http://www.diymobileaudio.com/forum/...1-post151.html

 

Well that's not the response I was hoping for. Thanks for the link guys. I was really hoping to do one layer of dynamat tar-like material to cut the noise down, but seems you need a lot more than just that (layer wise and diff materials).

So, without doing it "the real way" as OldSchool said....there is nothing worth doing? I'm not looking to completely cut out the drone. But reduce it a little more. As well as I have noticed heat coming through the floor board and a little toasty by my feet on hot days (no AC on)

 

It will help some, but whether it is worth it to you is subjective. I've seen some suffer from the psychoacoustic effect stating that Dynamat alone made a HUGE difference to others, like my former employee with the Camaro SS, who could not believe they spent so much money on something that didn't help at all.

On the other hand, adding deadening alone to my 97 Civic did make some difference. The main source of road noise in that car was the paper thin sheet metal resonating at speeds of 35 MPH in the city. I think it was the combination of my all season tires, the crappy Louisiana roads, and the paper thin sheet metal that caused a vibration that was similar to a groan while in the city. I added eDead to the trunk and doors only, and most of that noise went away. I had also treated the trunk in spots with Damplifier Pro to stop it from ringing due to my subwoofer.

Unfortunately the only photo I have of where I spot treated my trunk lid with Damplifier Pro:

 

op I say IMO don't waste your money or time, end results *disappointment*
I used the best sound deadener *carpet* and all it did was add unwanted weight. The only way to rid yourself of drone is replace your mufflers. I was told the rear window is the culprit of the unwanted noise. If you want a quiet ride get a family car, the stang is meant to hear the noise. This is my end results and I'm not getting into a argument about how wrong I am, I spent enough money to call myself stupid and I'm leaving it at that, but if you do get your noise level down please post your true results. I say it's not worth it. GL!

 

Good catch LS What... I failed to mention that noise transmitted through the glass will ALWAYS get you in the end, no matter how much time, money, and effort is spent on deadening, foaming, and mass loaded vinyl.

 

This is why I like to run stuff by people on here before doing projects (if I'm unsure of the result). Well I do have options, and I'm not gonna turn this into an exhaust thread...BUT I still have my stock midpipe with only the front 2 cats (rears were taken out but not by me). So that's an option, and I dont even think going to an o/r H will help...I'm leaning toward the fact that there are no cats which is making this problem.

Like always in these cars with exhaust, I get it around 1K under load in 4th and 5th and 2k in all gears. The 2k spot is more the muffler loudness..not really the drone of them.

I was thinking....do they make sound deadener made to block out specific frequencies? All sound happens at given frequencies, so what about making material to block the low end ones (drone)?

Maybe that's what they already do, and it's me not being fully educated on these materials. I have seen tar and foam type materials...that as much as I know.

 

I will agree that it does little to nothing for road noise and like I said, it took forever to put on. The only reason I used Dynamat was because after I upgraded my stereo, all my schit was vibrating. It eliminated the vibration, but my exhaust still drones a lil around 3000-3750 rpm (LTs, no cats, Flowcrappers). I think you have more of a muffler problem. Maybe try a bit more mellow staight-thru muffler (if there is such a thing) if you like the tone they give you. Maybe Borla Stingers or LM2s. Magnapacks are right up there with LM1s. If you get your exhaust tinkered with, try LTs also

 

I wish my drone was up around 3K to 3700....I'm barely in that rpm range daily driving.

Kinda disappointing that the myths about all this sound deadening stuff is mot true...or at least not as much as manufacturers make it out to be.