S212 interior road noise

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phobos

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Feb 17, 2019
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Location
Farnborough - Hampshire
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S212 E350cdi
Right, Saturday! Measurement day.

Got a SPL meter from Amazon and a massive 13 tog duvet...

At both 50 and 70 mph I got with SPL meter around 75-77 dB.
With the duvet where the spare tyre is located, i got 72-75, so between 2-3 dB of gain which is pretty good!

Also done an interesting test with a A4 piece of paper.
Put the piece of A4 paper between the door seals, close the door and ty to pull the paper.
Driver and passenger rear door - need to do quite a lot of strength to get the paper out
Driver and passenger front door - easier than rear doors, but still some strength required.
Tailgate - super easy to pull out the paper ( there is only 1 rubber seal as all the other doors have opposite rubber seals )

I would expect that the tailgate seal should seal better, but having said that, I hear road noise, not necessary wind howling noise..

Has anyone replaced door seals and saw a reduction in road noise ? Or should I consider better soundproffing?

Many thanks
 

190

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Mar 4, 2015
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Cheshire
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2009 W204 C180K
I have an Excel file of dB measurements at idle and various speeds. It covers over 1500 cars but I can't post it as it's not a permitted file type. Here's a couple of screen shots of some Mercedes models. It's a few years old so doesn't cover the latest models.

Diesels are obviously noisier than petrol and an interesting observation is that newer versions of the same petrol models are not necessarily quieter which I believe is due to the adoption of direct injection engines which are inherently nosier than port injection.

C class.JPG

E class.JPG
 
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phobos

Active Member
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Location
Farnborough - Hampshire
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S212 E350cdi
I have an Excel file of dB measurements at idle and various speeds. It covers over 1500 cars but I can't post it as it's not a permitted file type. Here's a couple of screen shots of some Mercedes models. It's a few years old so doesn't cover the latest models.

Diesels are obviously noisier than petrol and an interesting observation is that newer versions of the same petrol models are not necessarily quieter which I believe is due to the adoption of direct injection engines which are inherently nosier than port injection.

View attachment 103666

View attachment 103667
Hi 190,

Thanks for the information, very informative.
Do you know where the measurements took place, UK or Europe as the tarmac might have played its part.
 

190

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Mar 4, 2015
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Location
Cheshire
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2009 W204 C180K
I couldn't remember where it came from as I've had the data for a few years, so I was surprised how easy it was to find the the source simply by doing a web search for "dB at idle"


It looks to be German

desktop
 
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phobos

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Feb 17, 2019
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Location
Farnborough - Hampshire
Car
S212 E350cdi
Thanks, looks like the tarmac played a big role.
Did some more experiments today and tried 4 different types of road and you can definitely hear the different between different tarmac takes some of them being much noisier than others...

Oh well, I will try to should deaden the wheel arches and properly sound proof the spare wheel well and see what results I get!
 

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