PDA

View Full Version : IVA Noise measurement: dBA or dBC ?



KevinW
09-03-19, 12:54 PM
Can anyone tell me whether the noise measurement is made on the dBA or dBC scale?
The IVA manual does not specify.

I think it should be dBA, but whilst playing with the meter I noticed that dBC ups the recorded noise level of ambient background noise quite a bit.

dave
10-03-19, 09:31 AM
dBA. Is what they should test at.

KevinW
10-03-19, 11:25 PM
Thanks Dave.

AKCobra
11-03-19, 12:51 PM
Has to be below <100 dBA @ 4750 RPM.

Alan.

aaronjb
11-03-19, 02:59 PM
Has to be below <100 dBA @ 4750 RPM.

Only if Kev's engine makes maximum power at 6300rpm, surely? The manual says "run the engine at 3⁄4of its ‘maximum power’ speed", although does follow it up with "Where the engine maximum power speed is not available, thetest may be carried out at 2/3 of engine maximum design speed" - so if he doesn't know maximum power speed then I guess it's 3/4 of the redline.. even then, on a 428, I'd assume max RPM is going to be ~5-5,500rpm - Kev?

KevinW
11-03-19, 07:52 PM
yup, my prescribed engine speed is below 4000 rpm.
The limit is indeed less than 100dBA, but it is actually 99dBA max, so 99.5dBA is a fail.