Measure the sound and write the ticket

I wish to raise issue with Robin Levinson’s article regarding motorcycles and noise pollution (“Measuring the noise,” July 19).

While there is no real fault with Levinson’s use of her phone as a sound level meter, there are serious issues in her methodology.

The first example shows a loud car stereo registering much lower than a group of people talking as they passed by.

What Levinson missed is that sound intensity is greatly affected by the distance from the source to the listener — so much so that if you increase the distance between the two by a factor of three, the sound intensity will drop to barely more than a tenth of the previ- ous reading.

This is why a group of people talking, albeit loudly, on the sidewalk registered as “louder” than a car stereo a few meters further away.

Secondly her statement that, “it’s high school physics that the faster a vehicle moves, the louder it sounds” is simply incorrect.

The engine noise produced by a vehicle is affected by engine rpm, throttle position and exhaust design among many other factors but vehicle speed is not one of them.

This is why revving your engine to redline at a stop light is louder than cruising down the road at 50 kilometres an hour with the engine near idle.

Finally, I wish to comment on the article’s conclusions and Richard Harrison’s suggestion of banning modified exhausts.

Ignoring the issues of how the police would determine if a bike had aftermarket pipes it misses the real issue: obnoxiously loud vehicles.

With simple and cheap hand-held meters police can quickly determine if a vehicle exceeds a predetermined level and if so issue a citation.

This directly addresses the issue while allowing owners to freely modify and customize their vehicle so long as they do not exceed the sound restrictions. A.D. Barnes C.B.S.