I went ahead and installed a 1' x 1' sheet of hushmat in the inside of each door panel (on the inside of the door against the metal) and adjusted the doors slightly, but haven't had any time to drive around to see a change yet. The hushmat was only 30 bucks so not much lost on an experiment.

 

"With all due respect", I now dispute my own conclusion... LOL...

I've found out that Bitumen-based materials are NOT the best for use in extreme temperature.

Exposed to hours of direct sun in the desert, the temp' inside a door can get to 80+ºC (176+ºF).
Such sustained temp' has a bad effect on Bitumen-based materials, both on the material itself and on its sticking capability, in the long term.

The better material for very hot weather is the synthetic rubber, and out of those materials, it seems that the best is the the SecondSkin Damplifier Pro.

 

To deaden sound, there's a combination of "density" and "thickness", where I mentioned both of these items in my original post. A general rule is you need 1/4 the thickness of the audio's "wavelength" to effectively reduce a particular range of frequencies. Thus, the "thicker" the material the lower the frequency you are able to effectively block out.

So basically, low bass frequencies have the longest "wavelengths". Your tire road noise falls into the lower frequency ranges of audio.

As an example of something, where you may have experienced these "physics" occurring in the real world. If have ever stood outside of a large arena or night club, you can usually still hear the "bass" frequencies of the audio inside. As soon as a door is opened, you can now hear the higher frequencies of the audio. The thicker the walls, the less of these low frequencies you would hear outside the club.

This is also why the JK is bad for outside noises compared to other vehicles. The JK doors are thinner than most doors on other vehicles. Other vehicles you can actually mount a speaker inside of the door...not so with the JK, due to how thin it is.

 

any one have any pictures of where they are putting this stuff on doors and other locations? I see how they do the hard top but am curious in seeing the other spots and how they look. Mine is all bedlined so itd be best if there were hidden.

 

I second what Rednroll said ...

 

Rednroll and desertbuzz,

The question is what we look for -- sound deadening, or outside noise reduction.
(I know the term are overlapping, but you understand what I mean.)

I wouldn't deaden the sound in a vehicle (or room), because it would also "deaden" the sound quality of music.
I also think that too much sound deadening in a Jeep is counter productive.
I want to feel every aspect of the Jeep, especially so when offroading.
Part of that feel comes through hearing. I want to hear nuances of the engine sound, a "thump" from a tire, a faint squeak that wasn't there before, etc'.

My personal interest is first of all heat insulation, then some noise reduction.
Luckily, noise reduction materials typically also insulate heat.
Therefore, I do not intend to insulate the whole Jeep, but just to treat the main heat and noise sources, which are the hardtop and the 4 doors.
Stripping the doors will be a good opportunity to add insulation and make the doors better speaker boxes.

I'm not in a position to dispute you two experts... but I do know a thing or two about sound.

"A general rule is you need 1/4 of the audio's "wavelength" to effectively reduce the of a particular range of frequencies"

The wave length of 20 Hz is ~17 meters
If we go up to 300 Hz, the wave length is ~1 meter (~3 ft).
Following that rule means insulating material thickness in the range of 25 cm to 4 meters... good in theory, but quite unrealistic.
There're additional ways to block long waves, like we see in every sub woofer box.

Anyway, while the Hothead Headliners are still on the way, the Red Arc smart dual battery isolator just arrived, so installing a second battery will be the next mod.
So... which battery would be the most quiet ?

 

A lot of American muscle/hot rod cars guys use this stuff, but prefer the Lowe's brand. Not too sure why though.

 

When did this ever become a debate?? We described ways to reduce outside noise.


Good for you. We were answering the OPs question...not discussing your personal preferences.


Good for you. Try taking off the doors and all effects of any material added will be eliminated. Again....a question was asked...we were offering help in answering it. Once again, no one really cares about your personal preference because it does not pertain to what was being asked by the OP.



That's absolutely correct, where NOBODY said you would ever be able to achieve complete blocking out of that sound. You're "dampening" the sound, thus reducing the level of that sound...not "blocking" it. You just proved my point of what I described with my night club example. Night club and concert hall walls can be well over 3ft thick...yet you can still hear those bass frequencies through them.

Again, Care to elaborate? There is no way to "block" long wavelengths sounds from entering or exiting a vehicle. You can only do things in an attempt to reduce their level and to reduce other parts from resonating with those sound waves. Go read up on the construction of anechoic chambers and get back to me on some mythical sub woofer box that "blocks" long waves.

Obviously not.

 

By what you say, I now understand that, by "sound deadening", you meant partial noise reduction. I took "sound deadening" at face value – complete insulation. English is not my native language, and I may not be familiar enough with the specific jargon – in English - regarding sound.

I replied your response to my post, and not your answer to the OP -- see post 43.

There was a misunderstanding on my part of the exact meaning of "sound deadening".
There was a 'misunderstanding' on your part of who you're replying...

I'm disappointed to see that your post is a verbal attack, and the last two words are plain domineering.
The best virtues of this forum are that it pretty much lacks personal attacks, and threads stick to the point.

I thank you for the factual information.

 

Guys guys guys ... Plllleaaaase let's not take this conversation there .
We're all Jeep fanatics and we're all here to help each other .

And as far as sound proofing improvements to any vehicle, the OP as well as any member here have enough info to go ahead and do it.
This is the objective... and let's keep it fun