Sound Deadening Project

[johnloov]

Here is a quick update. Drove on some extremely course highway patches.

I did find some of the absolute worst highway sections to drive on today, where the entire inside of the cabin was shaking and buzzing. The entire car's interior, including the top mirror light sections, the dashboard, etc.

I was going about 75mph and when I hit this extremely course and broken asphalt the DB's did hit ~87-89db's ( 93.4 max ) then as soon as smoother asphalt came in it dropped down to 78.2 db.

The conclusion is, the Type R with those tires, combined with the extra thin metal construction, is a very loud and stiff tin can.....

But there is something you can do to help mitigate some of that noise.

Drive on very smooth roads, and dampen the interior.

Before dampening I remember these numbers being close to 99-100+ decibels. Food blender territory on course roads.
Driving on the extremely rough patches of highway ( interior was rattling everywhere ):

Same road, same speed, after the rough stretch of road:

 

[TW00Si]

This has been an interesting thread. So is the takeaway that the most noise to reduce is from the wheel well by padding the liner and then the four doors? What’s the recommended material for the doors? That’s something I think I’m open to doing.

 

[johnloov]

This has been an interesting thread. So is the takeaway that the most noise to reduce is from the wheel well by padding the liner and then the four doors? What’s the recommended material for the doors? That’s something I think I’m open to doing.

You will need dampening and sound proof foam to do it properly. The wheel wells are easiest maybe to start with, but the inside made the biggest difference. I’m happy I did both. For sure. For some the doors maybe easiest. All of it is time consuming and tedious work. It felt like I did yoga for 50 hours.

First I did the doors overkill. Full deadening inside the door, and that acoustic foam. I drove around and noticed there was still a lot of noise entering car from the rear wheel wells and trunk. Once I over killed that as well, it made a massive difference. The front wheels are not inside the cabin but those rear wheel wells are, and they transmit directly into the cabin. The trunk, tap on that spare wheel metal area, it’s a tin can.

For me, for sure it was sound insulation of the interior, doors and trunk, interior wheel wells, and the exterior wheel arches helped a bit also, which was not picked up on the decibel meter. The exterior wheel arches helped further mute the tire roar.

For the doors, I took the advice from the Resonix guy. In his videos, he says while you are in there, the more the better.

check my links in this thread, I used Amazon deadening, which works great, doesn’t cut open hands like some others. And then I used acoustic foam that also had dampening. Links are above in this thread

For the wheel wells I used a thinner foam, as the clearances were tighter and it fit perfectly

https://www.amazon.com/gp/aw/d/B0BNBV7WK6?psc=1&ref=ppx_pop_mob_b_asin_title

 

[johnloov]

Here is the sound difference
1) Tin can - no sound deadening no acoustic foam
2) sound deadening ~90% coverage of that panel
3) sound deadening + acoustic foam
Massive difference

 

[Robo7]

Wow I thought my area had rough roads! Out of curiosity I grabbed some db readings on my drive into work today with my Apple Watch. Never broke 70 db which isn’t too bad. Interesting thread. Glad this worked for you!

 

[johnloov]

Wow, that seems very very low, try using this app IOS phone Decibel X ( but make sure you turn off your car play bluetooth and wifi to ensure it uses your micrphone from iPhone )

Curious what reading you get at 65 MPH

 

[johnloov]

Here is great video link explaining the basics of sound proofing a car

 

[Robo7]

Wow, that seems very very low, try using this app IOS phone Decibel X ( but make sure you turn off your car play bluetooth and wifi to ensure it uses your micrphone from iPhone )

Curious what reading you get at 65 MPH

Ok so I ran this app on my drive home with all connections turned off so it would only use my iPhone mics. On good roads (which is most of my drive) I averaged 70 db @ 70 mph. On the rough roads I saw 80 db at 60 mph. The spikes in the screenshot are hard acceleration and the peak was running over train tracks @ 60 mph.

 

[johnloov]

Ok so I ran this app on my drive home with all connections turned off so it would only use my iPhone mics. On good roads (which is most of my drive) I averaged 70 db @ 70 mph. On the rough roads I saw 80 db at 60 mph. The spikes in the screenshot are hard acceleration and the peak was running over train tracks @ 60 mph.

Wow that’s shocking. Are you on stock wheels suspension and tires (stock tire pressure)?

thanks for recording that, totally befuddled why yours is much quieter.

my car is a 2024 purchased new 2 months ago fresh off the boat

what year is your car?

 

[Robo7]

Wow that’s shocking. Are you on stock wheels suspension and tires (stock tire pressure)?

thanks for recording that, totally befuddled why yours is much quieter.

my car is a 2024 purchased new 2 months ago fresh off the boat

what year is your car?

It’s a completely stock ‘24 with 3k miles on it on PS4S. Engine sound was turned to Comfort. Roads here a pretty smooth overall where I live. I’ve never thought the interior noise was obnoxious in this car. It’s certainly much louder in my FL5 than my Odyssey (that’s a quiet vehicle). Had a ‘22 Si previously and the FL5 is slightly louder inside from what I recall.

I was surprised that folks have felt the need to add noise insulation based on this thread as I never felt the need to. I suppose if you have extremely rough roads though it might be necessary. I’ve been on some roads undergoing construction where the road noise was insane and if your roads are like that then I totally get it.

Update: ran the same test again this time with no phone case. Same exact result.

 

[johnloov]

Thank you for your feedback and data. I’m sure your data is accurate since you got the same results on your iPhone and watch. And I can’t believe Honda makes inconsistent cars.

We do have roads here in Silicon Valley also that are like glass, but I am still way over 75-78dbs at 70mph after deadening ….. and it was much louder before. Other variables could be iPhones mics, cases, dirt inside mic ports, but still 10db is like 2x in loudness.

I’m heading for a road trip to race Laguna seca Saturday and will collect more data.

Hmmmmmmmmm

would be good to get more data from others.

what’s everyone else reading??

Seems like many are finding the new gen civics need sound insulation and some people must have iron ear drums

 

[Imped]

I replied to the thread earlier so I guess I'll do it again.

I don't have hard app data, but I'm on 255/40R18 Continental DWS06+ tires. I've used these on several other cars, including my previous Golf R. They are excellent and are quieter than the factory PS4S's.

Other mods that could impact noise - PRL RMM, front strut tower brace and, as mentioned prior, I have already added sound deadening to the trunk floor.

This isn't a car that I would describe as excessively loud (no louder than my similarly setup Golf R). After reading every one of your replies, yours seems to be a unique case. With that said, I'd still like to quiet mine down a bit.

 

[Robo7]

Thank you for your feedback and data. I’m sure your data is accurate since you got the same results on your iPhone and watch. And I can’t believe Honda makes inconsistent cars.

We do have roads here in Silicon Valley also that are like glass, but I am still way over 75-78dbs at 70mph after deadening ….. and it was much louder before. Other variables could be iPhones mics, cases, dirt inside mic ports, but still 10db is like 2x in loudness.

I’m heading for a road trip to race Laguna seca Saturday and will collect more data.

Hmmmmmmmmm

would be good to get more data from others.

what’s everyone else reading??

Seems like many are finding the new gen civics need sound insulation and some people must have iron ear drums

I would see if you can ride along in someone else’s FL5 on a road you are familiar with and see if there is a difference. I can’t imagine there would be that much difference between our cars unless they the factory made an error or switched a process/material mid-cycle. My car is an early ‘24 purchased in January.

 

[johnloov]

I replied to the thread earlier so I guess I'll do it again.

I don't have hard app data, but I'm on 255/40R18 Continental DWS06+ tires. I've used these on several other cars, including my previous Golf R. They are excellent and are quieter than the factory PS4S's.

Other mods that could impact noise - PRL RMM, front strut tower brace and, as mentioned prior, I have already added sound deadening to the trunk floor.

This isn't a car that I would describe as excessively loud (no louder than my similarly setup Golf R). After reading every one of your replies, yours seems to be a unique case. With that said, I'd still like to quiet mine down a bit.

I heard about the continentals being more quiet. Seems you also have more sidewall with your 18s. 255/40R18 Continental DWS06+ tires

I know on my wife’s eqe suv with summer continentals with the Q technology drop a full 9dbs. They are an amazing summer tire. I’m sure they will develop high performance Quiet tires in the future. We took it to the shop and they gave us the same exact car but with one wheel size up and all seasons, and you could instantly tell it was a few dbs maybe 1-2 louder at 70mph.

I did drive a 2023 type r in a test drive in Dallas ~6 months ago an unfortunately it was in a rainy flood day and it was at 78db, at 60mph, so it was not a fair comparison as the rain was dampening the road noise.

It is true that the decimeter doesn’t show the full range of sound compression and noise. Currently my car below 40 miles an hour is about 5dbs over my EQE SUV and you can barely hear a loud train go by even from 25 feet away. But if you hit a really rough patch on the road, everything inside the car shakes buzzes and hums, and it’s still way better than before on a smooth road at 75.. I may use lightweight foam on the floors as well. I just want a car that’s fun as hell, manual, and doesn’t make my tinnitus start ringing after a drive.

i’ll collect more data this weekend thanks everyone for your input.

 

[johnloov]

Here is another project on a Honda Civic Sport.

Has anyone seen under the floor carpet what our cars look like?

I did notice under the rear TYPE R seats, it did have some dampening stickers vs this type of robotic glue as in the civic sport below.

It looks like the owner was still not satisfied with the road noise, and moved to sound proof the entire floor.