Inside Consumer Reports Test Labs: For leaf blowers, sound pressure and sound quality determine how annoying the noise can be
Consumer Reports News: June 18, 2010 11:28 AM
Leaf blowers are handy, work-saving tools, but if you've ever used one or heard them being operated, you know how noisy they are. So big is the noise issue that some communities have banned leaf blowers altogether.
And several municipalities nationwide have added a clause specifically about decibel rating for leaf blowers in their noise ordinance, for example prohibiting models that exceed a sound pressure of 65 to 70 A-weighted decibels, or dBA, at 50 feet.In response, manufacturers have adopted a voluntary noise standard based on sound pressure, again, measured in A-weighted decibels. With most new leaf blowers, you'll spot this decibel rating on the device and/or its packaging or in the user manual, and on the manufacturer's site.
Some experts contend that municipal limits don't address the issue of noise since sound-pressure-based decibel ratings don't account for sound quality. Sound pressure is basically a physical measurement of sound waves, while sound quality captures the psychological perception of sound.
"You might have a fan blowing at 50 dBA and fingers running down a chalkboard at 50 dBA," says Les Blomberg, director of the Noise Pollution Clearinghouse, a nonprofit organization in Montpelier, Vermont. "The effect of those sounds will be very different on the body."
Because sound quality takes into account such attributes as harshness and harmonic content, it's considered a better measure of the impact of noise on the human ear.
One model we've tested illustrates the difference between decibel rating and sound pressure. The Husqvarna 356BFx backpack leaf blower has a claimed dBA of 64; in our tests, we measured a slightly higher decibel rating.
But in terms of sound quality, the 356BFx is perceived as both having less shrill tones and being one of the quietest models tested for our upcoming September 2010 review of leaf blowers. "To my ear, it definitely has a lower pitch and a whooshing sound that are less grating than the nasally whine of other blowers," says project leader Peter Sawchuk, who stars in our video (above) pitting a leaf blower against a rake.
Husqvarna credits improved components including the engine, fan housing, and insulation for the gentler noise produced by the 356BFx backpack leaf blower. A specialized muffler might also contribute to this leaf blower's sound quality.
Of course, a quiet leaf blower isn't worth considering unless it works well. The $450 356BFx offers excellent sweeping and loosening power and easy handling, making it an expensive but appealing leaf blower if you have lots of leaves and debris to clear. While the 356BFx will be louder than raking up leaves, your neighbors might find the Husqvarna 356BFx appealing too.
When it comes to the neighbors, avoid using your leaf blower early or late in the day. Check with your town about any restrictions on noise and hours of operation. Also, always wear hearing and eye protection when using your leaf bower and keep other people and pets away from the work area.