What do the measuring parameters of a sound level meter mean?
Lp instantaneous sound level
Leq equivalent continuous sound level
Le exposed sound pressure level
Lmax maximum sound level
Lmin. Minimum Sound Level
Lpk peak sound pressure level
LN time rate sound pressure level (LHI L5,L10,L50,L90,L95,LLO,LAV)
Lx Measurement time greater than this sound level accounts for X%
The peak value of the waveform remains Lpeak Lcpeak . Lceq .
Ltm5 5-second sound level * maximum value
Equivalent continuous sound level
A-weighted sound level can better reflect the subjective perception of the human ear towards the intensity and frequency of noise. Therefore, for a continuous steady-state noise, it is a good evaluation method. However, for a fluctuating or discontinuous noise, A-weighted sound level appears inappropriate. For example, traffic noise varies with vehicle flow and types; For example, when a machine is working, its sound level is stable, but due to its intermittent operation, a machine with the same sound level but continuous operation has a different impact on humans. Therefore, a problem was proposed to evaluate the impact of noise on humans using the time averaged method of noise energy, namely the equivalent continuous sound level, denoted as "Leq" or "Laeq · T". It represents the magnitude of noise during the same period of time using a continuous and stable A-sound level with equal sound energy. For example, there are two machines with a sound level of 85dB, * * working continuously for 8 hours and * * working intermittently, with a total effective working time of 4 hours.
Obviously, the average energy applied to the operators is twice as much as the former, which is 3dB greater than the latter. Therefore, the equivalent continuous sound level reflects the actual amount of noise energy that a person receives when the sound level is unstable. It is an equivalent quantity used to express the time-varying noise.
