This graph has several vertical bars, which may
at first be confusing, but the telling information is at the far
right where it is marked "Average". This is the data that
appears on the label attached to the blower. The ANSI Standard
requires that the operator stand fifty feet from the microphone
and then take eight measurements to be averaged for a final
value. Each measurement is taken 45 degrees from the previous
position as the operator rotates in place 360 degrees, hence the
other bars on the graph.
This data shows the ECHO gasoline powered unit
to average exactly 65 dB(A). The other units are all higher,
with the Black & Decker unit (the one having the straight
discharge pipe) being the loudest. This clearly shows that the
"Quiet" gasoline powered leaf blower is more than comparable to
electric when it comes to sound. It also shows how surprisingly
loud an electric blower can be at about 74 dB(A).
It is important to note that sound is measured
in Micro Pascalís and then converted by the measuring device to
a logarithmic value called decibels. An easy way to compare
sound levels is to consider that for every 6 dB(A) change, the
sound level measured in Micro Pascalís either increases by a
factor of 2 or decreases by half. In other words, 71 dB(A) is
twice as loud as 65 and 77 dB(A) is twice as loud as 71.
Seventy-seven dB(A) is therefore four times as loud as 65. In
this comparison, 65 dB(A) represents a 75% reduction in sound
from 77dB(A). A more detailed explanation is available on page 6
of the pamphlet found at the following link:
For the commercial operator, the quiet gasoline
powered leaf blower will be preferred over electric because it
has better performance and is not tied to a building or
generator by an electric cord. Battery powered units are totally
unacceptable because of their extremely low performance and
serious lack of endurance.