(September 15, 2023 at 1:34 pm)BrianSoddingBoru4 Wrote:(September 15, 2023 at 1:24 pm)Deesse23 Wrote: Wrong
DBs are multiplicative, in that they provide a multiplicative scale for numbers.
Adding DBs equals MULTIPLYING values.
Example: +20db = x 10, +40db = 10 x 10 = 100, +60Db = 10 x 10 x 10 = 1000, -20db = 1/10, etc
Thus the machine with +20db more noise level is TEN times louder than the other*. APPROXIMATELY the 100db machine is dominant (assuming the sound waves do not create interference, cancel each other out n stuff. Lets not go down that rabbi thole today), because the total air pressure is only x1,1 of the dominant one.
That way you can easily display wide ranges of numbers in plots, or display certain behaviours that are multiplicative, making them look "Linear" in the "multiplicative realm" of DBs.
*in terms of air pressure..... but heres the catch: With +20db the air pressure is TEN times more, but human ears work in a LOGARITHMIC scale, just like DBs and we have subjectively linear perception according to a db scale! That way we can distinguish between a sound of a fly and a starting 747 next to us, two sound events separated by 10^12 in terms of sound pressure. We dont perceive the plane being gazillions of times louder, but only tousands of times, according to the multiplicative perception we have. We kinda perceive an event with 60+db (compared to another), which is x1000 times louder, in fact like 3x (+20db) louder.
According to my sound meter, my shop vac/dust extractor runs at 80dB, my table saw at 105dB. When I run both together, I get a reading of 105dB.
Am I looking at this wrong?
Boru
No, but the 105dB is about 300 times as loud as the 80dB. So, when you add, that is a total of about 301 times the 80dB item, which is still about 105dB (within a margin or error).
