How Accurate Are The Decibel Meter Apps?

[sprogthedog]

Thinking of going to Bedford later this month.

My Gti-6 has an aftermarket backbox on it, and it's a bit loud.

I got one of these decibel meter apps, and it measured 90db @ 4000rpm.

So question is are these apps fairly accurate?

[MyVTECGoesBwaaah]

What phone? It is going to be based as much on the quality of microphone as much as the app, while it would give a rough idea there would be no replacement for a real reading.

[gruffalo]

In my experience no not at all reliable.

Tested my Cerbera at 98dB on an Iphone app and they let it in at Brands with a "we'll call that 105" and a wink.

Warm summers day as well.

[sprogthedog]

App is called Decibel 10th. On iPhone 6.

[CrutyRammers]

Generally considered to be pretty bad at the upper end, which is what you need. However, the eBay special sound meters cost about a tenner and have repeatedly shown to be very accurate. I used one for my iva as have others and it read the same as vosa 's expensive one.

[E-bmw]

^^^^^ wot 'e said.

I found the same CR, app db meter said my exhaust was ok for track days at 94db, TDO says nah mate at 109, £10 ebay jobie says 109 also.

[Stephanie Plum]

Bear in mind that at Bedford the static is relatively forgiving at 101db. It's the drive by that'll send you home….

[QBee]

Stephanie Plum said:

Bear in mind that at Bedford the static is relatively forgiving at 101db. It's the drive by that'll send you home….

Strangely I found the opposite - i was 103 dB on a damp morning on the static test, but then the Porsche GT3 behind me in the queue failed at 103 too.
I have never failed the drive by, but then I am not daft enough to drive past the things at maximum revs. They are easy to spot on the sighting laps.