An LEQ value indicate the steady state dB level which would produce the same sound energy over a stated period of time as the real time varying
signal would do, when using a 3 dB exchange rate.
LEQ(A) is defined as the A-weighted sound pressure level of a noise fluctuating over a period of time T, expressed as the amount of average energy.
Sometimes LEQ(A) is also called LAT - time averaged level. The LEQ(A) is widely used around the world as a noise index.
In general, the paranthesis that follow the dB indication eg. (A) indicates what the dB is referring to eg. A-weighting, or it could refer to
frequency bands like (500 Hz) or (8kHz).