decible testing....dba or dbc

[avinesh]

Recently got my exhaust system certified, it failed the first time as it was hitting 102db so got it fixed an it went down to 95db. Today i tested my exhaust system at my mates muffler shop an guess what it was well below 95, reason being we used dba to filter the testing an when we put it on dbc it shoots up to around the 95 mark, i think mine got certed on dbc which reads a lot higher an as far as i know it is ment to be measured using dba as thats more closer to human hearing......so i got my exhaust system restricted for no reason ........just cheked out some noise legislations of vehicles an they all seem to be measured on dba......

http://74.125.155.132/search?q=cache:r- ... clnk&gl=nz

[xsspeed]

dBA is a weighted scale to suit the range of frequencies that the human ear can hear.

without digging up old notes etc dBC will put more weighting on higher/lower/middle frequencies than what dBA does, so its not really comparing apples with apples when you compare them.

If they (cops etc) are using a single dB level I'm 90% certain it will be dBA measured at 1metre or something like that.

[Mr.Phreak]

It should be read on dbA, do you have any reason for thinking it was certed otherwise?? Or just cos your mates meter is reading lower??

[avinesh]

It should be read on dbA, do you have any reason for thinking it was certed otherwise?? Or just cos your mates meter is reading lower??

Well it read almost exactly what the certifier guys meter read on dbc setting an on dba it was well below. I knew the exhaust is too quiet to be 95 decibles.....Even the law states noise levels in DBA not DBC........

[Mr.Phreak]

Which is why I think it's weird the certifier would test on dbC, I'm not even sure the gear is capable.

FWIW, most affordable hand held meters are crap.

[avinesh]

Which is why I think it's weird the certifier would test on dbC, I'm not even sure the gear is capable.

FWIW, most affordable hand held meters are crap.

Well theres no harm in finding out instead of just wondering so im gona find out, an the car passed with 3 resonators one of which is not even straight flow it is as restrictive as it gets an a 1 inch baffle on the back an even then it just manged 95 decibles which really shocked me...

[avinesh]

My mate told me he got failed once as well an its a good thing he checked what noise filter setting they were using an sure enough they were using dbc so he got them to test it on dba an he passed with around 90 decibels.....