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Discussion Starter · #1 ·
Just started this yesterday, but the plan was to get all 4 doors done by the end of the long weekend.

I just upgraded from my Bose system with new speakers, a 4 channel amp and a powered sub. Been driving around for about a week and realize that although I can turn up the volume, getting this done will increase the quality of my sound.

I’m doing the trunk next while I work up some familiarity and courage to do the roof. But as it is, I may end up taking the car to a stereo specialist. I don’t think I can remove the headliner without wrinkling it or staining it.

Here are some obligatory pics:








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Discussion Starter · #2 ·
So on Friday, I measured the noise levels while driving into work at 68 mph (cruise control).

I searched and found some document on measuring in-cabin noise. It basically said to measure at drivers ear level, use Weighted C for 55-85 dB (A for <55 dB).

Here’s my “before”:





I figure as long as my measuring method is the same, I can compare “before” and “after”.


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Discussion Starter · #5 · (Edited)
Edited (My apologies, the table is wrong! I finally dug out my meter manual and found that the column for Frequency is actually a switch setting for anticipated dB range. So, it looks like without a better meter that has frequency control, there is no measurable difference with this meter. ):
29376


I did another measurement after installing the sound deadening materials in the doors and trunk. (This part is wrong: Looks like it only helped at 100 Hz frequency and all the other frequencies measurable by my old-school Radio Shack meter remained unchanged.)

But on a personal level, I could hear a difference after the first door. It's hard to describe... it's like the sound from all the other speakers were "loose" and rattled/bounced around the inside of the door before I heard them, while the sound from the one door I finished sounded like a direct shot to my ears.

After installation, it seems as though the bass got louder.

With the radio muted, the car is quieter of certain sounds. Road noise is still there, but different. It's kind of eerie that while visually seeing my location on the freeway and expecting to hear a certain sound, the sound is just different. Like driving another car that I'm unfamiliar with.

While adding the sound deadening material is actually a pretty simple task, the execution is a lot of work. I can see why it takes as much labor as it's often quoted. Sore fingers and back aside, it is a very worthwhile mod.

I'm going to drive around as-is while deciding on whether or not I want to do the roof myself or have someone do it. I've been doing some research on the kind of materials intended to go up on the roof and it seems like in addition to the standard butyl/foil layer, a second layer of foam goes on top of that.

Has anyone removed the headliner? How easy was it? Thanks.
 

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2022 Bolt EUV Launch Edition Ghost Grey
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Any tips on getting the door panels in and out without breaking the upper retainer clips? I have a bunch of sound deadening material that I bought ages ago with the intention of doing what you just did, but fears of breaking things have deterred me from proceeding.

Also, I’m guessing you did away with the white factory vapor barrier?
 

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Discussion Starter · #7 ·
Regarding the metal clips at the window sweep trim, pop all the other retainers first, then pull straight up in one quick/forceful movement. This will pull the window sweep off along with the panel. After that, remove the sweep from the metal clips (5 clips per door) and use a flathead screwdriver and needle nose pliers to remove the metal clips from the panel.

Then “reset” the whole thing by placing the metal clips back on the door then put the window sweep back in place on the door. So when you are ready to put the panel back, the clips will now just go into the slits in the door panel.




I actually reused the plastic water-proof liner from each door. I placed the sound deadening sheet right over it but the area covered is much larger than the plastic. It is held in place all around the plastic barrier so it will stay put. On the other hand, if I ever need to open things up again (like to replace a window motor), it’ll be easier to get to it.


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Thank you for the great info with pics! It’s probably the best piece of advice I’ve come across in terms of getting the entire panel out. I have the CF manual and it’s really useless in that regard.

So aside from the clips on the window sweep panel, all the other retainer clips are of the round, plasticky variety (ie, identical to the ones found at the bottom of the door panel)?

And if I’m understanding your process correctly, you first removed the plastic vapor barrier, applied the butyl deadening sheets to the outer sheet metal, reattached vapor barrier, then applied more butyl on top of the vapor barrier?

Your results have inspired me to revisit this project that I’ve long abandoned and otherwise forgotten. Thanks again!
 

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Discussion Starter · #9 ·
Thank you for the great info with pics! It’s probably the best piece of advice I’ve come across in terms of getting the entire panel out. I have the CF manual and it’s really useless in that regard.

So aside from the clips on the window sweep panel, all the other retainer clips are of the round, plasticky variety (ie, identical to the ones found at the bottom of the door panel)?

And if I’m understanding your process correctly, you first removed the plastic vapor barrier, applied the butyl deadening sheets to the outer sheet metal, reattached vapor barrier, then applied more butyl on top of the vapor barrier?

Your results have inspired me to revisit this project that I’ve long abandoned and otherwise forgotten. Thanks again!
Yes all the other clips are either the gray or yellow and round. I actually probe around the bottom of the panel near the speaker for a gap built in where I can get my fingers in to start pulling.

Your description of the order of what I do is spot on.


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A few observations on the measured data.

1. The car does a good job cutting off the most humanly audible range around and above 1kHz. What gets through is the low range, which is road noise. It overlaps with the bass of the audio system.

2. The mat helps lower the cut-off frequency from 105Hz to 95Hz.

3. The noise power is mostly in 75Hz to 105Hz. The mat basically takes out 1/3 of it, or lowers it by 1.2dB. It may not seem a lot in dB scale but it is clearly observable, and it does help the bass in your ear. Don't forget human ears are probably more sensitive in 95-105Hz than below. The 1.2dB may be more significant than what the number indicates.

So it works. I'm now tempted. You probably will get more return doing the wheel wells than the roof, I think.

-TL

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Discussion Starter · #11 ·
A few observations on the measured data.

1. The car does a good job cutting off the most humanly audible range around and above 1kHz. What gets through is the low range, which is road noise. It overlaps with the bass of the audio system.

2. The mat helps lower the cut-off frequency from 105Hz to 95Hz.

3. The noise power is mostly in 75Hz to 105Hz. The mat basically takes out 1/3 of it, or lowers it by 1.2dB. It may not seem a lot in dB scale but it is clearly observable, and it does help the bass in your ear. Don't forget human ears are probably more sensitive in 95-105Hz than below. The 1.2dB may be more significant than what the number indicates.

So it works. I'm now tempted. You probably will get more return doing the wheel wells than the roof, I think.

-TL

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I’m targeting the roof because I have a Thule roof rack and 2 bike racks up there. From day 1 of installing the crossbars, I can hear a very noticeable increase in wind noise at freeway speeds. The sound doesn’t really have an abundance of bass. That’s why I believe it will work. This is my main motivation.

I’m thinking both the butyl/foil material with a closed cell foam product on top of that, like Dynaliner, should do the trick.


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I’m targeting the roof because I have a Thule roof rack and 2 bike racks up there. From day 1 of installing the crossbars, I can hear a very noticeable increase in wind noise at freeway speeds. The sound doesn’t really have an abundance of bass. That’s why I believe it will work. This is my main motivation.

I’m thinking both the butyl/foil material with a closed cell foam product on top of that, like Dynaliner, should do the trick.


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The mat under the roof should work well against the higher frequency wind noise.

-TL

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Discussion Starter · #13 ·
My apologies to everyone, the table is wrong! After reading Tangolima's description of sound dampening, I wanted to reconcile certain things in my head, so I finally dug out my meter manual and found that the column for Frequency is actually a switch setting for anticipated dB range. So, it looks like without a better meter that has frequency control, there is no measurable difference with this meter. Sorry for the confusion.
 

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Oops. That makes me scramble to look at the data again.

So the readings are for total power within the wide frequency spectrum of weighting C. Looks like it is about 95dB. The valid range setting should be either 90dB or 100dB, so all the other rows can be discarded. You can't go back to the before measurement. But you can redo the after measurement.

Funny thing is in 90dB range, it indicated 95dB. But in 100dB range, it indicated below 90dB. It is contradictory. You may want to repeat those two tests. Chances are the mat reduces the total power. It is interesting, so please keep us updated.

On the other hand, it doesn't matter what the readings say. If you think it works, it works. It the way audiophiles work, is it not?

-TL

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Awesome, thanks again for the tips. Will definitely revisit once I can eke out some time for this. Process seems to be straightforward enough. Just wanted to make sure I don’t irrevocably break something in the process. :p
 

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Discussion Starter · #17 ·
Yeah, sorry about that. What you stated made a lot of sense, but my numbers the way I believed /thought, did not match exactly. That’s when I pulled out the meter’s manual. I hadn’t used it since the last time I set up a home theater system, which was more than 10 years ago.


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Discussion Starter · #20 ·
Well, in for penny...

I have about 18 sq ft of the Siless butyl/foil material left which is about what I need for the roof. Any extra will be strategically placed as a second layer.

I just ordered 20 sq ft of Noico Red 315 mil foam to go on top of the butyl layer.

I’m all in now, but first I need to figure out how to remove the headliner without staining or wrinkling it.

I’ll report back how it goes.

Wish me luck.


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