### Properties of DB Scales

In every kind of dB, a*factor of 10*in amplitude increase corresponds to a

*20 dB boost*(increase by 20 dB):

*dB per decade*. That is, for every factor of in (every ``decade''), the amplitude drops dB. Similarly, a factor of 2 in amplitude gain corresponds to a 6 dB boost:

dB

A function which is proportional to is said to fall off
*dB per octave*. That is, for every factor of in (every ``octave''), the amplitude drops close to dB. Thus, 6 dB per octave is the same thing as 20 dB per decade. A

*doubling of power*corresponds to a

*3 dB boost*:

dB

Finally, note that the choice of *reference*merely determines a vertical offset in the dB scale:

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Specific DB Scales

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Logarithms of Negative and Imaginary Numbers