"Never Enough Money" wrote in message
oups.com...
Fein Turbo II is rated at 58 decibles. The Shop Vac "Quiet Deluxe 6.5
HP" is rated at 82 decibels.

The rule of thumb I know is that 3 decibles corresponds to a doubling.
Thus the Shop Vac Quiet Deluxe 6.5 HP is 24 decibels louder, or 3 db +
3 db + ... + 3 db (8 times), or 2x2x2x2x2x2x2x2 = 2 to the 8'th power =
256 times louder.

Is that correct? If so, holy moly!

As you may know, decibels correspond to a logarithmic scale, and a +3dB
increase requires a doubling of the power to produce the sound. After a bit
of looking, it seems that the perceived loudness is closer to being
proportional to the the dB rating. So, the Shop Vac would be perceived to
be about 40% louder than the Fein. All of this is, of course, very
subjective as it depends on the person listening, the sound frequencies
involved, etc.

todd