Hello William, I don't know where I came up with 3 plus 3 plus 3 then plus 1.5 is required to get 10. A mystery to me, except that the post was done in a hurry. So what are you saying? Benande takes the position as does Bernhard that 6db is a doubling of loudness. Perhaps this is corrected for perception. What is it? Regards, Robin Hufford "William R. Brohinsky" wrote: > 3dB is a factor of 2 for power. (note power is expressed in watts, > joules or some such, and as such cannot be negative. The components of > power, for instance, in electronics, voltage and current, are a > different unit, and in fact 6dB is a doubling of voltage.) > > It is nice to remember in here that dB is a ratio only, and 'absolute' > dB values have an implied reference. Good usage states the reference, so > dBm is 'referenced to 1mw (one milliwatt, 1/1000 Watt), and dbV is > referenced to 1volt. Sound pressure levels have their references, and > weightings (different curves which are applied to 'correct' readings to > match the sensitivity of things like ears). > > By the way, while most of the quoted numbers are right for sound power > (a less vague term than 'loudness'), the total of 3+3+3+1.5=10.5, and > that is an increase by a factor of 11.22; dB is log-base-10, so a > magnitude (factor of 10) is 10dB. > > A handy reference(?): > 1dB = x1.25 > 2dB = x1.58 > 3dB = x2 > 4dB = x2.51 > 5dB = x3.16 > 6dB = x3.98 > 7dB = x5 > 8dB = x6.3 > 9dB = x7.94 > 10dB =x10 > 11dB=12.5 (note, this is 1dB x 10, or 1dB +10dB: adding dB multiplies > the factors like adding exponents!) > 20dB=x100 > 30dB=x1000 > (ie, decades of dB are powers of 10. Thus, 30dBm is 1dBW, because 1mw x > 1000 = 1 W) > > The useful ones to remember are > 1dB = x 1-1/4 > 3dB = x 2 > 5dB = x 3 > 7dB = x 5 > 10dB = x10 > Y0dB = 10^Y > > and, if you're familiar with logarithms, you probably have divined (or > remember) that > dB=10(log(factor)) > and > factor=(invlog(dB)/10) > > With calculators (and all the OS's in use have scientific calculators > built-in) it's not hard to deal with dB. > > raybro > > Robin Hufford wrote: > > >Actually, I believe 3 Db is about a doubling of "loudness". 3 is a > >doubling plus 3 more makes a quadrupling plus 3 more makes eightfold at > >9 Db. Then 1.5 Db makes approximately tenfold or an order of magnitude. > > > >Regards, Robin Hufford > > > >Bernhard Stopper wrote: > > > > > > > >> Part 1.1 Type: Plain Text (text/plain) > >> Encoding: quoted-printable > >> > >> > > > >_______________________________________________ > >pianotech list info: https://www.moypiano.com/resources/#archives > > > > > > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives
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