Audio Engineering

50 Chapter 2

Table 2.5 : Preferred Reference Labels for Acoustic

Name Defi nition

Sound pressure squared level LP  20 log ( p / po ) dB

Vibratory acceleration level La  20 log ( a / ao ) dB

Vibratory velocity level LV  20 log ( v / vo ) dB

Vibratory force level LF  20 log ( F / Fo ) dB

Power level LW  10 log ( P / Po ) dB

Intensity level LI  10 log ( I / Io ) dB

Energy density level LE  10 log ( E / Eo ) dB

Table 2.6 : A-Weighted Recommended Descriptor List

Term Symbol

A-weighted sound level LA

A-weighted sound power level LWA

Maximum A-weighted sound level Lmax

Peak A-weighted sound level Lpk

Level exceeded % of the time Lx

Equivalent sound level Leq

Equivalent sound level over time ( T ) Leq(T)

Day sound level Ld

Night sound level Ln

Day–night sound level Ldn

Yearly day–night sound level Ldn(Y)

Sound exposure level LSE

Table 2.7 : Associated Standard Reference Values

1 atm  1.013 bar  1.033 kpa/cm^2  14.70 lb/in^2  760 mm Hg  29.92 in Hg

Acceleration of gravity: g  980.665 cm/s^2  32.174 ft/s^2 (standard or accepted value)

Sound level: The common reference level is the audibility threshold at 1000 Hz, i.e., 0.0002 dyn/cm^2 ,

2 1 0 ^4 μ bar, 2 1 0 ^5 N/m^2 , 10 ^16 W/cm^2