However the immense range of human hearing, 0.00002 pascals up to 200 pascals, means the pascal is not practical for everyday use. Fortunately the sound pressure level in decibels, detailed below, neatly solves this problem.
|Sources at 1 m||Sound Pressure||SPL re 20 μPa|
|Rifle||200 Pa||140 dB|
|Threshold of pain||20 Pa||120 dB|
|Pneumatic hammer||2 Pa||100 dB|
|6 dB = twice or half the pressure||1 Pa||94 dB|
|Street traffic||0.2 Pa||80 dB|
|Talking||0.02 Pa||60 dB|
|Library||0.002 Pa||40 dB|
|TV Studio||0.0002 Pa||20 dB|
|Reference Sound Pressure||0.00002 Pa||0 dB|
6 dB = a factor of 2 in sound pressure (double or half the sound pressure)
10 dB = a factor of 3 in sound pressure
20 dB = a factor of 10 in sound pressure
● Note 1: unless otherwise specified, the reference sound pressure is 20 μP for airborne sound and 1 μPa for sound in media other than air.
● Note 2: unless otherwise specified, the sound pressures are understood to be expressed in root-mean-square values.
Absolute Sound Pressure is also known as the Sound Pressure
● Note: the band may be specified by its lower and upper cut-off frequencies, or by its geometric centre frequency and bandwidth. The width of the band may be indicated by a modifier such as one octave band (sound pressure) level, one-half octave band level, one-third octave band level.
See also • the Effective Value Definition IEC 103-02-03
● Note: unless otherwise specified, the reference sound pressure for airborne sound is 20 μPa.
Not be confused with the Equivalent Continuous Sound Level Definition : IEC 801-22-16
● Note: if frequency weighting is not specified, the A-frequency weighting is understood.
See also Peak Hold, True Peak and Peak-to-Peak.
See also • other Standard reference levels.