Installed some sound insulation this weekend

[BimmerFan]

I also polished and waxed the car, but no one needs to see a picture of a shiny black car to prove it.

One of the few complaints I have about this car is the amount of road noise. To save weight (I presume) Caddy has left off sound insulation in large portions of the car, and it seems that most of the noise comes from those huge rear tires, so since I had some leftover Dynamat from another project, and it was perfect work-on-the-car weather Sunday afternoon, I went for it.

Below are pictures of the removed trunk trim and how it looked when I finished. I did, as some will undoubtedly want to mention, a half-assed job. I did not feel like removing the computers, amplifiers, battery, etc. to cover everything like I should have, but even getting just the "easy" areas can still make a difference. Part of what Dynamat does is reduce the frequency of the metal so that it resonates less, reducing the boominess and higher frequencies. Or maybe lower frequencies. Who knows? Dynamat is also a real PITA to deal with, as it is stiff and very very sticky, so you can't easily slide it into tight spaces.

I did not do a before and after sound measurement because a) traffic was bad Sunday and I didn't feel like it and b) the last time I did something like this, it was a negligible measured difference. It does work though, as I could tell a bit of a difference driving into work. It's not so much that it's quieter, but the character of the noise has changed. Also I noticed that the wind noise from the driver's door seems to have increased in volume, which tells me that overall it's a bit quieter.

Would I do it again? Well, if I had to buy the Dynamat and do it, probably not. But since I had leftover and it wasn't being used for anything else, then sure, it was worth it (being basically free).

I will add though that it's literally a PITA to crawl in the trunk and do this stuff, especially at my age. It's not so much the crawling in there and working in cramped spaces as it is trying to get out of the trunk. And then stand up. Insert old man emoji here -->

Woe is me.

 

[Gilley]

Dynamat isn't fun to install. Looks good though.

 

[Mcard23]

funny, I want to do the opposite lol. Far too quiet inside for my taste (give me more blower and exhaust please). Looks good tho

 

[Neveready]

I also polished and waxed the car, but no one needs to see a picture of a shiny black car to prove it.

One of the few complaints I have about this car is the amount of road noise. To save weight (I presume) Caddy has left off sound insulation in large portions of the car, and it seems that most of the noise comes from those huge rear tires, so since I had some leftover Dynamat from another project, and it was perfect work-on-the-car weather Sunday afternoon, I went for it.

Below are pictures of the removed trunk trim and how it looked when I finished. I did, as some will undoubtedly want to mention, a half-assed job. I did not feel like removing the computers, amplifiers, battery, etc. to cover everything like I should have, but even getting just the "easy" areas can still make a difference. Part of what Dynamat does is reduce the frequency of the metal so that it resonates less, reducing the boominess and higher frequencies. Or maybe lower frequencies. Who knows? Dynamat is also a real PITA to deal with, as it is stiff and very very sticky, so you can't easily slide it into tight spaces.

I did not do a before and after sound measurement because a) traffic was bad Sunday and I didn't feel like it and b) the last time I did something like this, it was a negligible measured difference. It does work though, as I could tell a bit of a difference driving into work. It's not so much that it's quieter, but the character of the noise has changed. Also I noticed that the wind noise from the driver's door seems to have increased in volume, which tells me that overall it's a bit quieter.

Would I do it again? Well, if I had to buy the Dynamat and do it, probably not. But since I had leftover and it wasn't being used for anything else, then sure, it was worth it (being basically free).

I will add though that it's literally a PITA to crawl in the trunk and do this stuff, especially at my age. It's not so much the crawling in there and working in cramped spaces as it is trying to get out of the trunk. And then stand up. Insert old man emoji here -->

Woe is me.

It looks like you did a really nice job, professional looking IMO. The front tires have foam inside, too bad we can't track down more of that stuff for the rear tires which would help as well.

I know they sell spray insulation foam specifically made for sound deadening which could work well in hard to reach areas. It could be sprayed on the outside between the tire lining on the metal structures.

Did you consider that or have ever worked with it?

 

[jbawden]

I'm surprised no one is challenging you on the road noise complaint. On most surfaces the car is quiet, but some road texture absolutely roars through the cabin. I want to squash the road noise, but increase the exhaust volume inside the cabin (I don't want louder exhaust).

 

[Neveready]

I'm surprised no one is challenging you on the road noise complaint. On most surfaces the car is quiet, but some road texture absolutely roars through the cabin. I want to squash the road noise, but increase the exhaust volume inside the cabin (I don't want louder exhaust).

I agree too, I was playing devil's advocate. I think the car is quiet and refined in the right modes, a little too much in the engine/exhaust note department. I'm so thankful there is no drone. I can't recall the specifics, but the team designing the exhaust went through more than 30 iterations to find that perfect exhaust tone. I think it's fantastic.

To the OPs concerns, road noise is subjective. Depending on where you live, the roads and climate can have a huge impact on sound isolation. Plus everyone's ears are unique so certain sounds resonate more to others.

 

[1Evil55]

This thread makes it feel more like a Cadillac forum now. Funny how some want more noise, less weight..

 

[Grainofsand]

Good work! I'm sure installing it underneath the seats and carpets will nuke the road noise albeit adding a few lbs

 

[BimmerFan]

I'm surprised no one is challenging you on the road noise complaint. On most surfaces the car is quiet, but some road texture absolutely roars through the cabin. I want to squash the road noise, but increase the exhaust volume inside the cabin (I don't want louder exhaust).

I agree too, I was playing devil's advocate. I think the car is quiet and refined in the right modes, a little too much in the engine/exhaust note department. I'm so thankful there is no drone. I can't recall the specifics, but the team designing the exhaust went through more than 30 iterations to find that perfect exhaust tone. I think it's fantastic.

To the OPs concerns, road noise is subjective. Depending on where you live, the roads and climate can have a huge impact on sound isolation. Plus everyone's ears are unique so certain sounds resonate more to others.

It looks like you did a really nice job, professional looking IMO. The front tires have foam inside, too bad we can't track down more of that stuff for the rear tires which would help as well.

I know they sell spray insulation foam specifically made for sound deadening which could work well in hard to reach areas. It could be sprayed on the outside between the tire lining on the metal structures.

Did you consider that or have ever worked with it?

I get that, it's a trade-off when adding insulation to make the car feel/sound like an old Brougham rather than a 21st century high performance car.

I agree that the road surface makes a huge impact on the noise, as do the tires. These high traction (and I do love their performance) Michelin PS4S tires are a big part of the issue I believe. I'll likely go with some nice granny all-seasons when these wear down. Unfortunately, a large portion of my commute (this car is my DD) is on concrete highways, the remaining portion is on a highway under construction/expansion, and I suspect that most of the new surfaces (if they ever finish it...) will also be concrete. Around here (NC) most highways are concrete, and then when they get really old they start laying asphalt on top of them.

As for the foam... no, I have not tried it nor do I think I want to. My primary concern is getting any of that stuff on or in the various computers and wiring back there. The dynamat is going to get soft and gooey when hot, but it's not going to go liquid and run into stuff. The foam won't either - once it's dried, but during installation it can be messy and it expands enormously. So a small mistake could be catastrophic.

When I put in sound insulation in my C7 Corvette coupe (Corvettes have zero sound insulation) I put some foam sheets in between the fender liners and the body. I figured that the closer to the source, the better it would work. Of course, the liners didn't quite fit right afterwards...

 

[rubberduck]

The 5BW is quiet compared to other cars I’ve owned. Far better than my previous Mercedes. I also travel for work and drive a wide variety of rental cars and I don’t find my car any worse than those.

For the bad road surfaces I move the volume knob to the right.

 

[The_Ghost]

I've been thinking about doing this. I did it on my Solstice convertible when I redid the entire stereo system and it was a huge difference in interior noise. Yes, I know that the Solstice is a convertible, but it got rid of a lot of the squeaks and rattles that car had. Right now the Caddy doesn't have any of that, so not sure how much quieter it would make. I still have 16 square feet of deadner and not sure where else I could use it.

 

[V56]

Strangely, my 4VBW model year '22 is one of quietest vehicles I have ever owned. With all the windows shut I hear very little if any road noise.