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C-HR Soundproofing - a small and cheap project

37619 Views 35 Replies 15 Participants Last post by  mjvdzwet
So, after complaining several times that I find the C-HR too noisy, today I found a free hour to play and possibly test some insulation. A couple of weeks ago I bought self-adhesive waterproofing bitumen strip, protected with sheet of aluminium (1.5m2 for 8.80 GBP):
Ingredient Fluid Drink Gas Liquid

Since the time was very limited, I decided to go with the right side of the boot. Started by stripping the interior of the boot - easy task with only 3 10mm bolts from the luggage hooks. Everything is on clips which just need to be pulled lightly. Too bad I did not start taking pictures from here, but there are diagrams how to do it in the Rear Parking Sensors Installation Manual available in this topic. Now the pictures. :D

Stripped right side of the boot with one sheet already placed for testing, but not rolled yet. You can see the factory soundproofing, the roll with the bitumen strip and the roll I used to stick it to the car:
Automotive tire Hood Automotive design Motor vehicle Automotive exterior

Focus on the fender - no soundproofing neither on the wheel arch, nor on the fender itself:
Motor vehicle Automotive tire Automotive design Plant Vehicle

Inside after first two sheets of insulation:
Hood Window Automotive lighting Automotive design Motor vehicle

20 minutes later and advancing (already getting dark):
Hood Automotive tire Engineering Auto part Electric blue

Finished in the dark with the right side of the boot covered:
Automotive lighting Hood Motor vehicle Building Engineering

Next steps are to finish the boot and the doors for which I will use rubber-based sheets. On top of this insulation I will most probably put a locally produced carpet under-felt.

When there is again some warm weather and free time, To be continued... :D :D :D


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Thanks Juliano - really interested t hear what effect this has
Garry said:
really interested t hear what effect this has
You won't hear any
^See what I did here? :D
So, time for an update. Yesterday the weather was very nice and warm, so after installing the chrome trims from AliExpress I decided to move to the soundproofing of the doors. The boot is almost completed. This is becoming a short guide, but here is the truth about our C-HRs and their insulation.
With the driver's door (LHD) being closest to me, it was the obvious choice for first attempt. It all starts with the removal of the button panel. It is being held by 6 clips and it just pops up when pulled upwards:
Automotive tire Bumper Fixture Automotive exterior Vehicle door

Next step is to unscrew the three screws holding the door panel. They are located behind the door knob and below the buttons panel we just popped:
Car Hood Light Vehicle Grille

After the screws are gone, the panel pops out just by pulling it. You can start from the bottom to the sides until it drops in your hands. You need to hold it because the door wires and the cable for the LED ambient light are still attached. All of them are easily disconnected and reconnected again. Once the panel is removed, I had a pleasant surprise - instead of using the usual nylon foil, Toyota closed the servicing openings with two tightly fixed plastic panels:
Hood Automotive tire Trunk Motor vehicle Automotive exterior

The photo was taken during re-assembly and has vibrodamping tape on the inner door panel.

The second surprise is that the non-JBL speakers are riveted and their replacement requires drilling:
Automotive tire Audio equipment Carbon Motor vehicle Gas

The third surprise was the worst and probably the main reason for the wind and external noise complaints. The outer door has no vibro-damping material. None. Just a bare sheet of metal, glued to the rods inside, but the glue itself was already compromised and was no longer doing its job. Did not take picture of this, but this is how it looks after I added the bitumen tape:
Hood Wood Automotive lighting Road surface Asphalt
Hood Vehicle Car Automotive tire Motor vehicle

Covered around 80% of the outer door with the stuff and put everything back. The door is now completely different - after driving for about 50km I can confirm that the road noise was coming from the rest of the doors and from the wheel arches. No noise from the driver's door. Furthermore, the sound from the speaker improved significantly although it dies below 40Hz.

I made a short video of the difference before-after when you knock on the doors. Just remember - the car is left hand drive:


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How did you apply the tape on the outer panel?
Did you do it by just putting your hands through the existing holes, or dis you remove the complete outer panel?
That video shows an impressive reduction in high-frequency vibration.
mjvdzwet said:
How did you apply the tape on the outer panel?
Used the existing holes and a roller. Today finished also the front passenger door and one of the rear ones. In addition I finally found sound dampener of my preference - it is an expanded foam soaked with fireproof material and very, very nice for sound insulation. Here it is called FireX with thickness of 20mm and for only 10.50€ per square meter. Bought 3 sq.m. which should be sufficient for all doors and the boot. Here are some pictures:

The rear door panels have 2 additional screws near the door handle:
Car Vehicle Hood Automotive tire Automotive lighting

Bare door with the nasty nylon and sticky, dirty glue of some sort:
Hood Motor vehicle Automotive lighting Guitar accessory Automotive tire

Door with added vibro- and noise- deadener, ready for the door panel to be installed:
Helmet Automotive design Rim Automotive exterior Sports equipment

The panel itself:
Automotive lighting Hood Motor vehicle Automotive design Flash photography

And with added sound deadener, freshly cut from the roll underneath:
Hood Motor vehicle Automotive lighting Sleeve Bag


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The project is now complete.
All four doors and the boot are vibro- and soundproofed following the steps for the rear door. The C-HR is now a different car and feels much more solid and expensive, just like a Lexus. All external sounds are much quieter and distant, the sound of the non-JBL system is almost perfect - all "hollow bass" is gone, mids and highs are clear. Even the engine is now distant and subtle when revving. I am sure if I put foam at the firewall it will dissapear.
And because I am thick enough, I did not measure the sound levels before. Now I will need to ask my dealer for a C-HR test-drive and compare before/after noise and sounds.

Cost of the project and links to similar materials in U.K.:
2 rolls of bitumen self-adhesive tape (3 sq.m.) - £17.40
4 sq.m. non-flammable acoustic foam 20mm. - £34.61
Hard roller - £13
Total: £61 and three full days, most of which spent in learning how not to do it. :lol: :oops:
I will give it a try as soon as summer arrives.
Have to work outside... To cold and rainy at the moment.
mjvdzwet said:
I will give it a try as soon as summer arrives.
Have to work outside... To cold and rainy at the moment.
This sounds like an amazing project! Really up for doing this too #mjvdzwet
Thanks to the photo's it looks like a do able project.

No good weather yet, tho.
Cant you get someone with same phone as you to download a db app and copy each others actions?
Very good idea, we can try this way as well. However I am not sure how accurate the test will be because there are also two very important factors: road quality (tarmac and tires) plus microphone sensitivity. This is why I wanted to try it with same phone and road. Anyway, I am using three phones:
- Samsung Galaxy Note GT-N7000
- iPhone 5s
- iPhone 6s Plus
Someone with one of these, please test the noise level at 80, 100 and 130km/h, respectively 50, 62 and 81mph. Post here the the app, phone and the results and I will try to test it as well.
Great idea..

I measured today on good tarmac 90km/h Ear level
74db almost 5db more than my 2015 mondeo.
Application thinks its a vacuum cleaner :D


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My Sony Z3 Compact gives the same value at the same speed. Phone was held in the center of the car by my passenger.
My phone is also Sony .. XA ULTRA
This morning I tested with the Galaxy Note and Sound Meter app. The result showed average 62dB at 90km/h and engine running. The app showed "Conversation" below, switching to "Quiet Library" from time to time.
At rest with ICE off the sound level is 23dB.
not sure where Toyota get their figures from but taken from my toyota web site, seems to be louder when not moving :?


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Thats funny .)
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