How loud is 43Db

[Christian McArdle]

Because it is a very useful concept and deserves a name. What would you call a decibel then? The unit formerly known as decibel? TUFKAD. Catchy. There are other dimensionless units you would have to expunge, of course. Percent (%) is a useful one that would have to go.

Your dictionary is wrong. It is used to measure power ratios (usually in oscillatory systems of large dynamic range). Sound power is only one of the measurements it is useful for. Amongst other things, it is also used to measure vibrations and to compare electronic signals, not necessarily audio in frequency or nature.

Christian. BEng (Electronic and Electrical Engineering)

[CRB]

Oh, it's not abstract, it's real enough. The point though, as already made in another posting, is that it is dimensionless.

CRB

[CRB]

Just in case any confusion has been introduced by talking about "types" of dBs, there is no such thing as a "voltage dB" or a "power dB". A dB is a dB, i.e. a specific ratio, which by definition is measured in power, but which can also be measured in voltage (or in current come to that) as long as the two measurements share a common impedance.

CRB

[Christian McArdle]

Provided that the ratio is adjusted in line with the variable's relationship to power. Power is related to the square of voltage, so multiplication of ten in voltage terms is not 10dB, but 20dB.

An example in numbers with a 1 ohm resistive load:

1V rms produces 1W (call this 0dB) 10V rms produces 100W

This is a 20dB amplification, as although it gives 10x the voltage it gives

100x the power, which is expressed as 20dB.

Christian.

[Suz]

Everybody's right!

Main Entry: deci·bel Pronunciation: 'de-s&-"bel, -b&l Function: noun Etymology: International Scientific Vocabulary deci- + bel Date: 1928

1 a : a unit for expressing the ratio of two amounts of electric or acoustic signal power equal to 10 times the common logarithm of this ratio b : a unit for expressing the ratio of the magnitudes of two electric voltages or currents or analogous acoustic quantities equal to 20 times the common logarithm of the voltage or current ratio 2 : a unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level 3 : degree of loudness; also : extremely loud sound -- usually used in plural

[Dave Plowman]

When dBs are discussed, you can guarantee as many different answers as questions. ;-)

[jacob]

Havn't time to catch up on this thread so this may be redundant - but

43 decibles is the sound level we are asked by env health dept not to exceed outside our boundary when we set up our joinery shop in new premises. 43 db being a measurement of the ambient sound in the neighbourhood and equivalent to a suburban street sound level. Its actually 43db level equivalent measured over a sample hour. I don't know if they actually measured it on location or merely took it from tables.

cheers

Jacob

[gittyupgoosies]

replying to Wdyw, gittyupgoosies wrote: Yes well I see mister Nat Phil! Ah hem! So 50 Decahillbillies is "low" eh? And

40 Decahillbillies is "extremely low" Ha! Tell that to the birds and the bees next time your trousers are down at your knees....The hills are alive with the sound of Muzak!

[gittyupgoosies]

replying to CRB, gittyupgoosies wrote: OMG! Who is this rough rider? Quasimodo? Yikes. Can we plz finish the prostate exam?!