Units

Processing acoustic signals in Sound: Analysis and Specification requires the use of various units. All the units are presented in this page.


Unit	Symbol	Description
Decibel	dB	The unit of sound intensity. Decibel is a logarithmic unit that expresses the relationship or ratio between sound intensity (or sound pressure) and a reference value.
Decibel with SPL weighting	dB SPL	The unit of sound intensity with Sound Pressure Level weighting. The SPL weighting uses the smallest audible sound for the human ear as a reference level.
Decibel with A-weighting	dB A	The unit of sound intensity with the A weighting. The A-weighting refers to the sensibility of ear to pure tones with low sound pressure level, around 40 dB SPL.
Decibel with B-weighting	dB B	The unit of sound intensity with the B weighting. The B-weighting refers to the sensibility of ear to pure tones with a sound pressure level between 60 dB SPL.
Decibel with C-weighting	dB C	The unit of sound intensity with the C weighting. The C-weighting refers to the sensibility of ear to pure tones with sound pressure level higher than 80 dB SPL.
Hertz	Hz	The unit of frequency. 1 Hertz equals 1 cycle per second.
Pascal	Pa	The unit of pressure.