n7bsn wrote:
Francesca, do you know what spreading loss is?
Do you know how to calculate it?
Do you even know what it is?
Do you understand there are weighting scales?
As for your claim that the level is away from the exhaust (claiming the exhaust would be louder) some U of Alabama students did a study a few years back that your claim is, well, "it depends". They did several "beam pattern" runs and found enough variability in their results I would say "not proven" (yes I've actually read their report, have you?)
60 dB at 1 meter is the same measured energy as 60 dB at 7 meters. Yes if you are 1 meter away it would be louder then 60 dB
ktmrfs is correct, I've never checked my cell-phone "sound" ap, but I'm betting it's only good to maybe +/- 6 dB for accuracy and probably +/- 3dB for repeatability.
This is why I always reported sound as db/meter.
Based on my comparison of a calibrated traceable sound meters to inexpensive dedicated sound meters, I would be very suprised if the iphone accuracy is within 6db or even 10db around a verified 60db source.
Even with a calibrated sound meter surrounding terrain can make 3 or more difference in readings. A big flat grass area with no trees will give different readings than the same area with nearby trees and different readings than a paved parking lot.
However, to see how much louder they are than a new honda, why not go over to a honda dealer using your app, and measure the sound level from a new demo unit and then measure yours in exactly the same conditions. At least that will give you an idea of how much difference there is between a new one and your older unit.
