Noise levels inside vehicle

[alang498]

Have any members undertaken a test of noise levels within a vehicle ?

I thought my 1998 VW Passat 1.9 TDI was starting to sound noisier than usual and so downloaded an ap onto my android smart phone and measured a maximum level of 75 decibels at approx. 70 mph on the motorway. Around town it was registering in the 60s. The radio was not on and the windows were closed.

Apparently the ap can have a variation of approx. + / - 2.5 decibels depending on the microphone built into the smartphone.

Another alternative could be to purchase a decibel sensor from somewhere like Maplin but I heard the cheaper models are not particularly reliable for readings.

[Gary03]

That sounds excessively noisy to me!
Mine is about 59-61 db at 70 mph.

[alang498]

Thank you - could I ask what your vehicle is ?

I suppose things such as road noise and tyres will have an effect and cause variations ?

[Gary03]

Mine is a 55 plate B5.5, 1.9PD.
I bought it from a mate because it had very low millage but compared with my older 03 plate car (same car), it seemed noisy, as in lots of road noise! On investigation I found that the complete front and rear section of the under tray was missing on it, this alone made quite a difference.
He also had some cheap tyres on the back of it, again, this made a surprising difference. Its geeky I know, but I wanted it to drive like my older 03 plate Passat. After getting another under tray and a full set of decent tyres its now nice and quiet.

[JMR1]

Very interesting post about noise levels and what causes excessive noise. These trays ( very easy to check ) and tyre's will be the first thing to check when I get the chance to give my 03-A61.9 TDI its first long road trip, which may show up other defects as well given it has 130'000 Miles on the clock. but hopefully good design will show through, and it will live up to its name of being a bullet-proof and mainly trouble -free car.

[zollaf]

i down loaded an app to measure my s4's 'noisy' exhaust. anyway , both my audi's are nice and quiet so not bothered measuring them, but my landy does 95 db at 40 mph.