SkiMore wrote:
Am I correct in saying that the distance from the source affects the measurement and that there probably is no way of knowing the distance that harbor freight and honda were when the took the measurements?
When I compare specs of two products and see one is 3dB louder how do I correlate that to how much more annoying the louder one will be?
I guess I'm asking how do I make the best use of the dB spec?
Yes distance matters, the formulas to calculate a change in distance can be, complex. Spherical spreading is easy, but that neglects any effects the ground would present (ground might absorb sound, or reflect sound )
Measurement methods matter also.
From reading the HF book, they measure the sound in roughly the same way and at the same distance (23 ft) as Honda
Most people can hear a 3dB difference, most people can't hear a 1dB difference. So you could tell a 3dB difference in a side-by-side, but in daily use you probably wouldn't notice the difference.
For the human ear (varies with frequency) twice as loud is roughly a 8 or 9 dB increase (10 dB is ten times the energy)