Just saw this. Apparently a Fluence owner is not happy with the rain noise on the roof of the car. And when he opened up the roof, he found that paper board is used for soundproofing the roof.

Does anyone have any idea if this is a "standard" practice in using this material for this particular model, whether the overseas model only used this paper board, or is it Renault Malaysia (or Tan Chong) that used this paper board for soundproofing?

https://www.facebook.com/photo.php?fbid=102...size=1600%2C900

Let's leave the opinion whether paper is good, average or bad soundproofing material, although I for one wouldn't be too pleased to see that being used for soundproofing.

Back to the question, does anyone know if this is "standard" practice in using this material for this particular Fluence model, whether the overseas model only used this paper board, or is it Renault Malaysia (or Tan Chong) that used this paper board for soundproofing?

Where did you see it? Is that cardboard on your own car, assuming you drive the Passat?

There is no rocket science as in "there is no ordinary cardboard". It's either a cardboard or not. The difference in terms of noise insulation between a vehicle that has cardboard and one that does not have one is very minimal. It won't reduce sound of the rain drops a lot, in fact negligible. It will however change the tone of the rain drops to the metal roof by altering the frequency, but the difference will not be tangible. To EFFECTIVELY reduce the sound from the ie. soundproofing the roof, you will need mass or sound deadening material which can be a combination of different materials in the roof.

The cardboard is cheap, and it will work, just a tiny bit. If the difference is negligible, it might be a better idea not to put anything on the roof. By putting something on the roof, the car manufacturer has already thought of soundproofing the roof, in some ways. For just a mere RM50-100 worth of material, that would bring more tangible improvements rather than RM5 cost of cardboard pieces that are stuck on the roof. Might as well don't put anything.

Actually, the Fluence as with any other cars costing RM120k+/- being sold in Malaysia are cheap cars. They are only costly when they are subjected to taxes by the government when the cars are brought into the country either in CKD or CBU versions.

The distributor/dealer of the Renault *may* have cut the cost by omitting or replacing some things in the car, for instance this insulation material that is being used on this Fluence. Looks like nobody here knows if the Fluence models sold in the overseas market are on this same cardboard material .

Cardboard will not disintegrate. If it does, the material is likely a foam type, dense foam which is commonly used for soundproofing. It will deteriorate with heat and break into small pieces in time, turn to dust as you say. But not cardboard. Cardboard will stay the same for years. Cardboard is a material used for packing boxes, the same boxes that are used for LCD TV panels, amplifiers etc.

Different application you are citing there. We are talking about the roof, not some separation for back seat and boot or other parts of the car. Those can be introduced to reduce vibration or something else, other than noise.

Well. Those examples you cite, they may be cheap, but it serves the application. But not in the case of the roof of the car, when it is cheap but it actually doesn't serve the purpose, it is negligible in terms of soundproofing. Those things you pointed out, they may be necessary items not only for separation but support of the fittings in the car (not necessarily solely for soundproofing). Whereas the roof, you don't need to put anything on it as it is just fine. If you want to put something on the roof, it is better to put something that is effective than something that is not. But in this case, it is a case of cutting-cost, introducing something that will bring minor or negligible effects. Other than the showing of the car manufacturer (or distributor of Renault in Malaysia, either one), cutting-cost to this extent, choosing to use a cheap and ineffective material for soundproofing when you can spend a bit more, likely not more than RM100 to use something that is more efficient and serves the purpose.

It appears you do not have some basic knowledge on soundproofing. Those who are into hifi especially room acoustics will know that egg trays are not meant for soundproofing. It is more to provide minimal absorption and diffusion, a very cheap solution for music listening in hifi applications where people do not have budget for costly room acoustic products. For soundproofing, you need absorption, the higher absorption the better. Hence foam which is good in absorption. The denser and thicker the better as it will be able to absorb more, being a more effective soundproofing material.

By the way, there isn't any need to find out whether there is a difference with or without cardboard, and the need to do a comparison. I can tell you right now that if it's cardboard, in a blind test you will likely not be able to tell the difference in sound when it rains. Maybe in the frequency of 10 times you will get it correct in 5 tries.

I'm surely wasting my time with you. Not that I am an expert and validation isn't required. You can do all the test if you want. But as I have said earlier, the things will turn out as it will be. The most you will get reduction of 1dB or maybe 2 dB via dB meter. You may measure the readings and get a measurement. The sound levels may or may not go down if the cardboard is ineffective in blocking or absorbing the sound. In other words, it may not even go down 1 dB, no difference at all. The tone of the sound of rain drops may change, but the intensity remains.

As I have reiterated, a test can be done. Even if the measurements, (objective) are proven to have some "minor" difference in sound levels, subjectively if you take the blind test you will fail the test if your ears cannot pick up the differences.

Get it?

Sometimes, some things don't need validation. It just takes some common sense and experience, with some knowledge in room acoustics. You can do test and measurements, nobody is stopping nobody. I am not stopping you. In fact I will be happy if someone does the blind test! BUT, it will be a futile test as I have mentioned, with the cardboard, one can already expect the results.

But I have to say, some people claim to have GOLDEN ears and can pick up the most minute differences. However, in a blind test, they often fail.

Please don't call me an expert. I just have some experience. I used to use an SPL meter to measure the sound levels from my hifi system years ago, not some dB app built in handphones but a proper SPL meter. I'm not that techy anymore these days as I'm getting old.