What is Leq Sound Level?Primary Software: Primary Software Version: 4.0 Primary Software Fixed Version: N/A Secondary Software: N/A
Problem: The Sound and Vibration Toolkit has a VI named SVL Leq Sound Level.vi that returns a value called "Leq Sound Level". What is Leq Sound Level and what does it represent? Solution: Leq is a symbol that represents “Equivalent Continuous Noise Level”. Usually the signal that you are measuring is varying in amplitude. You can calculate the sound pressure (noise) level of an imaginary continuous signal, within a given time interval, that would produce the same energy as the fluctuating sound level that you are measuring. The calculation is relatively simple; the Leq algorithm just divides the integrated sound pressure by the total duration of the signal. The result is expressed in dB.
The VI SVL Leq Sound Level.vi is often used in conjunction with an AWeighting Filter to calculate equivalent continuous Aweighted sound pressure level. Equivalent continuous Aweighted sound pressure level is widely used around the world as an index for noise. It is defined as "the Aweighted sound pressure level of a noise fluctuating over a period of time, expressed as the amount of average energy." The result is expressed in dB(A), which gives a reasonable approximation of the human perception of loudness. Related Links: NI Sound and Vibration Toolkit Attachments:  Leq_Equation.JPG  LeqVI.JPG  Leq_pic.JPG
Report Date: 11/22/2006 Last Updated: 09/11/2013 Document ID: 43LD037E
