NVH DiY and Tested

cvkit17

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NVH, or Noise, Vibration and Harshness, is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. - Wikipedia, Feb 2013.

So what exactly is it? In other words: You sit in the car. The car runs, you feel annoyed by the noise e.g. tyre or road noise, rattling noise, tweaking noise, or even ur mother in law keep on nagging. Sorry I cant solve the last problem for you. You're on your own :rofl:

Too long exposure to certain level of noises would cause us crazy, or even death. So what is noisy and what is not, except the monster in law? Here is a few examples:

1. Jet tak-off (measured at 25m) : 150 decibel (dB) - eardrum rupture
2. Thunderclap, chain saw, oxygen torch : 120 dB - Pain to the ear
3. Motorcycle, farm tractor, garbage truck: 100 dB - Serious damage in 8hr exposure
4. Average factory, milling machine : 80 dB - Damage in 8hr exposure
5. Passenger car at 65mph at 25ft : 77dB - Arbitrary base of comparison. Annoyingly loud to some people
6. Office, background music, restaurant : 60 dB - Fairly quiet
7. Quiet suburb, conversation at home : 50 dB - quiet
8. Library, lowest limit of urban ambient : 40 dB - zzzzzZZzzzZzz krruuuh ~ :rofl:

What I did was trying to improve the NVH of my car, and test if I succeed. So how would I know if I succeed? Sound is measured in decibel, or dB in short. The usual frequency is the 'A' band. That's where dB(A) comes. Sound dB doesnt add up like 1+1 = 2, but in a logarithmic pattern. Ok dat's boring. Let me give an example: when two source of sound have the same dB (lets say you have two Monster in Law nagging the same thing at the same sound level), the add up amount of sound is 3.01dB. So if I can achieve an improvement that gives plus minus 3dB, i'm happy.

Ok. Lecture session done. Now's the practical session. What do I need? Sound insulation material, and if possible, a leng lui beside me of course. :smokin: Many people use polyethelyene foam as sound insulation with brands such as Insulflex or Superlon. For damping purposes, bitumen with butyl sheet is commonly used. For my case, I neither used Insulflex nor Superlon, but something similar. Trocellen. Same kind of material and serve the same purpose. Trocellen is not known for its purpose as sound insulation to Automotive dudes. But in fact, the manufacture OEM sound insulation panels for many automotive brands. What I used is actually for industrial purposes, commonly used to insulate ductings, chilled water pipes, etc. So not only do PE Foams improve sound insulation, they improve the heat resistivity too.

Measurement: I dont have a decibel meter and I cant manage to borrow one. But hey! I bet you dont know...we have smartphones!! Decibel measuring apps are available and they are quite accurate. With accuracy of plus minus 2 dB. But of course, not all apps could do that, so choose wisely. I am using "decibel 10th" btw, and it's quite accurate.

So lets start the pictures already !!! :slug: Oh ya, I'm doing it on a Myvi Extreme.


1. This is the P.E Foam I mentioned. 1.2m width, 10m long. Another roll is my friend's.
001_zps4a2666ad.jpg


2. The damping material I used. Bitumen + butyl sheet.
f03c0897-9bc4-40fb-bae5-382e2348a1a4_zps20269f06.jpg


3. Rear door. I used Dunlop Contact Adhesive to stick to it.
1f038016-02b4-436c-9413-09e4914a54af_zps792bd84e.jpg


4. Apply some on the PE Foam, and then on the place you wana stick as well. Stick and then apply pressure. As you can see, I used some damping material near the speaker. Once done, let the glue dry under a fan or ventilation to get rid of the smell.
35d4129d-43e1-4647-80ab-58ca90571797_zps4388667b.jpg


5. This is how it looks inside. Notice the large free area, that's where it vibrates the most.
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6. Stick the damping material...make sure all inch is sticked on the panel. Notice that there's two different material. The bottom one is previous insulation material being applied.
004_zps3a585cd1.jpg


7. I did not do two layers damping as I deem that it is unecessary. Just dampens the free area would do. So for the inner panel, I only stick some on big flat panels. DIY is all about cost efficient isnt it?
907f70bc-acd6-421e-9a81-681b81b5ffc7_zpsb7f88aa3.jpg


8. This is where the speaker would be, so I put two layers of dampening material (old bitumen + new one)
006_zpsf5d35e3d.jpg


9. As I did not do 2 dampening layers, I just cover up the holes with PE Foam to reduce noise travel.
007a_zpsab35532b.jpg


10. Moving to the front door. Open the triangle thingy first....
008_zps9dd6cb80.jpg


11. Open up the handle in order to take out the plastic panel.
009_zpsd0847e4b.jpg


12. For the front door, because there's no speaker there, I only dampen the free area and not whole metal sheet.
010_zps822e582e.jpg


13. In order to reduce wastage, must always measure and plan!!
011_zpsc0a92eba.jpg


14. Opps, perfect.
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15. Next, the upper firewall
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16. Open the bolt that secures the wiper.
013a_zpsb21801cd.jpg


17. Then disamble this thing out by sliding it outwards.
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18. There's a piece of clip that secures it. Pull it out from this clip.
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19. The clip at another side is red colour
016_zps15d31bb1.jpg


20. install some PE Foam on the plastic panel
018_zps1db8ae9a.jpg


21. I actually used both PE foam and Bitumen sheet on this. Bitumen first, then PE foam on top of the bitumen.
019_zps0d9132e2.jpg


22. More
020_zpscc5e309c.jpg


23. Sticked some on the inner side of the fender. Same thing, bitumen then PE Foam on top.
020a_zps57f5ea00.jpg


24. The rear boot floor...bare metal
021_zps7820c06c.jpg


25. Before and after
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26. Another before and after
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27. The bare part has this very hard metal so the vibration wont be much.
022_zpsf4a04c62.jpg


28. A layer of PE Foam on top of everything after that.
713996b3-cb5d-4d1c-905f-46465979df63_zps09281e1d.jpg


29. Remove the carpet and put some PE Foam here.
027_zps99eb1ab4.jpg


30. Stuffed the PE Foam under the carpet without any adhesive.
028_zps84a20396.jpg


31. Plastic panels at the inner side of the boot. Use PE Foam.
026_zpsca9a2235.jpg


32. The panel covering the spare tyre.
bb51ae49-99dd-4110-b2e5-b1e4f2c69b92_zps8b07042b.jpg


33. The middle plastic panel. At the seat belt that one.
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34. Front Floor. Same thing, stuffed PE Foam into it.
033_zps99bdc573.jpg


35.Open up the utility box and you'll see this. Yes it is a fan
035_zps68fe469d.jpg


36. PE Foam on the inner side of the utility box to absorb the fan noise.
036_zpsb84cca89.jpg


37. Sticked some on the firewall...inner side of the dashboard.
037_zpsb913ff30.jpg


38.Moreeee
038_zps04f2e559.jpg


39. The boot door. Open the plastic panel and put insulation inside.
031_zps734fa0d5.jpg


40. Stick some PE Foam inside the metal panel.
032a_zps8226c8c0.jpg


41. FDaun Pisang ~
041_zps6b916e66.jpg


42. Put some dampening material and PE foam on the fender, near the fender bar there. But this picture only shows dampening. I added PE foam afterwards.
042_zpsf6f13edf.jpg


43. My humble vegetarian lunch of the day ~
034_zps2dffa9ed.jpg


44. Finally, proceeded with the hood.
044_zpse9b301d3.jpg


45. I still have this much after the installations. So might wanna add more layers to some of the parts next time. Maybe I shall do the roof next. Previously didnt think of doing the roof as I wana reduce maily road noise.
046_zps9b635747.jpg


46. This is how I positioned the sensors, in this case, the microphones and earpiece.
IMG_2440_zps50778e70.jpg


NOW! THE TESTING AND ITS RESULTS EVERYBODY HAS BEEN WAITING FORRRRRRRR !!!

I did my testing at DUKE Highway, both started at 11p.m.

1. First Test. In the car porch, engine off, no movement.
001B4AFNS_zps2046d233.jpg


2. Second Test: In car porch, ENGINE RUNNING, idle.
002BFAFEngStart_zps1b0cd108.jpg


3. Third Test: In car porch, ENGINE RUNNING, AIR CONDITIONING ON.
003B4AFACON_zps91ca3b9d.jpg


4. Forth Test: Driving at 60km/h, no music, AC On
004BFAF60_zpsa8543227.jpg

5. Fifth Test: Driving at 110km/h, AC On. Note that the reading for 110kmh is lower than 60 which is weird. But take note at the maximum reading and the graph. At 60kmh there's less disturbance and averagely lower. Its just at that time, the reading was caught at 70dB.
005BFAF110_zps7a01806b.jpg


6. I sped up to 120km/h and this is what I got.
006AF120_zps01674203.jpg


7. And just for information, with all windows down and at 110km/h. But this was before the insulation is installed.
008WD_zps42097145.jpg



So there we are with respective readings. The effort resulted in 2-4dB decreased in noise level, which is a very good thing. It means that my effort isnt down the drain :rofl:

Personally, without seeing these data, what I can feel after installing the insulation:

1. Road noise level reduced, but not to the extend of heaven and hell
2. No more rattling noise when I blast the speakers!!! Previously there was some rattling sound which is very annoying made me canot turn up the volume too much.
3. ICE is improved. The music is now more solid feel.
4. Doors feel solid, especially the rear door.

The satisfaction level of completing a DIY = priceless
The adrenaline pumping feel to your heart when you nearly fucked up your DIY = also damn priceless :rofl:

Thanks for viewing. Please comment / suggest if there's any in your mind :driver::wavey::driver:
 
Good job there!

In same cases, you need good sticky glue to absorb the sound..dont just 'put it there'..
Similar to those glass tinting theory.

Just to share information, the sound would appear louder on very low and very high frequencies eventhough it registers the same dB on SPL meter.

And I don't think the mic on our smartphone can detect this very low and very high freq. Good speakers can produce frequency beyond human ear range( 20Hz-20kHz). Not smartphone.
 
typical questions i assume ur gonna get

1/ where u got the bitumen n how much
2/ where u got the Trocellen and how much
3/ how long did it take u to do
4/ can do for my car ah? how much u charge?

etc etc etc
 
HOW MUCH YOU CHAJ AH? :biggrin:

Nice job dude. What did you use to measure the decibles?
 
Good job there!

In same cases, you need good sticky glue to absorb the sound..dont just 'put it there'..
Similar to those glass tinting theory.

Just to share information, the sound would appear louder on very low and very high frequencies eventhough it registers the same dB on SPL meter.

And I don't think the mic on our smartphone can detect this very low and very high freq. Good speakers can produce frequency beyond human ear range( 20Hz-20kHz). Not smartphone.

Thanks! I think the smartphone app can give us a reference which is good enough. The app could measure sound at frequency from 4hz to 20kHz.

Only for those on car floor I just put it there..coz I think the weight will press it down evenly. A good piece of advice :wavey: other panels I used combination of contact adhesive and double side tape.

typical questions i assume ur gonna get

1/ where u got the bitumen n how much
2/ where u got the Trocellen and how much
3/ how long did it take u to do
4/ can do for my car ah? how much u charge?

etc etc etc

Haha..couldn't agree more!

1. Well the bitumen I got it from my friend's friend accessories shop. RM45 per sheet.
2. The trocellen I got it from my supplier at a low rate. I don't know how much he charges others so I would not disclose the price. Coz the main purpose of the trocellen he sells isn't for this haha.
3. It actually took me almost a week coz some days I just do one door panel only. But if I wer to compile all the works together...3 days.
4. Cannot!!! :rofl: that's the beauty of DIY haha

HOW MUCH YOU CHAJ AH? :biggrin:

Nice job dude. What did you use to measure the decibles?

Thanks bro. But y u no read my post :rofl::thefinger::rofl: I already mentioned there haha
Jkjk...I'm using "decibel 10th". But there's many many sound meter apps out there. Vibration meter also got!
 
Nice DIY you have done. Mind to share, do you feel your car is heavier? The sound insulation have significant decrease ( from yourselves - do you feel quieter ride)?
 
Trocellen......need emmmm.how much.where to find.hardware got ah?

Nope..cant find it at hardware shop. I'll ask my supplier and see if he sells separately.

Nice DIY you have done. Mind to share, do you feel your car is heavier? The sound insulation have significant decrease ( from yourselves - do you feel quieter ride)?

Heavier...nope. The PE Foam is actually very lightweight. I can lift the whole roll up with only 1 finger. The bitumen sheet however, weighs around 2kg. So I gotta exercise more and shed 2kg from my tummy :rofl:

If you ask whether i feel a quieter ride...well yes but its not very contrast. I'll gotta drive on concrete road to see if it improves alot.
 
Added this to my car just now to improve the air cond efficiency. :driver: Sorry dont have testing for this but I can assure you that it will definitely work :biggrin:
IMG_2579_zps16efed30.jpg


This is the piping from the condensing side. Will install some at the evaporating side too hehe
 
hi there,

the bitumen sheet can be purchase at Eneos OneUtama - it cost RM60 per sheet, which can cover 3/4 of door panel ( i guess)

anyway this is a great DIY

how about foam spray inside chasis frame? i plan to do so. besides good NVH reduction, it can strenghten bodyframe...
 
hi there,

the bitumen sheet can be purchase at Eneos OneUtama - it cost RM60 per sheet, which can cover 3/4 of door panel ( i guess)

anyway this is a great DIY

how about foam spray inside chasis frame? i plan to do so. besides good NVH reduction, it can strenghten bodyframe...

The one I bought is around RM50 per piece. Can cover one door per piece. I'm not planning to do chassis foam coz it looks messy to me and kinda costly.

I've found a better material to the p.e. foam I used but I have not contacted the supplier so I don't have samples...its called air silent and usually being used inside ductings to reduce noise. Perhaps it would work better
 
RM50? May i know where is the location?
I plan to do on my grand livina, before proceed to my inspira

Foam spray is one-way-ticket desicion,once done it cannot be remove.. Maybe i need more consideration...
 
RM50? May i know where is the location?
I plan to do on my grand livina, before proceed to my inspira

Foam spray is one-way-ticket desicion,once done it cannot be remove.. Maybe i need more consideration...

I don't think foam spray would reduce much noise. Vibration yes. Your chassis will be more rigid and firm and perhaps less rattling noises. My friend helped me to buy the bitumen...the shop is located in klang. You can also find those bitumen deals from LYN market. There are a few guys selling...

Bitumen sheet reduces outer noise whereby P.E foam reduces inner noises. ICE sounds better with PE foam.
 
great post! so many pics
will be doing my own car soon with proper db meter.

i do sell insulflex, bitumen(grey type,2mm thick), fender bitumen spray and a meterial like 3m thinsulate (200gram grade)
 
great post! so many pics
will be doing my own car soon with proper db meter.

i do sell insulflex, bitumen(grey type,2mm thick), fender bitumen spray and a meterial like 3m thinsulate (200gram grade)

Thanks. Look forward for your testing :biggrin:
I might need fender spray next time when I change rims to bigger ones haha
 
Thanks. Look forward for your testing :biggrin:
I might need fender spray next time when I change rims to bigger ones haha

your post is really inspiring :D

just got my stock of spray for fender, gonna do it tmrw. but no DB meter now :(
 

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