What Is Leq Sound Level?
Primary Software Version: 2014
Primary Software Fixed Version: N/A
Secondary Software: N/A
NI Sound and Vibration Software has a VI named
Leq represents a value known as Equivalent Continuous Sound Level. Usually the sound pressure level (SPL) you are measuring varies in amplitude over time. Leq, on the other hand, is the imaginary constant SPL that would produce the same energy as the fluctuating sound level you are measuring over a given time interval.
The equation to calculate Leq divides the integrated, normalized sound pressure by the duration of interest of the signal. The result is expressed in units of decibels:
It is important to note that the Leq calculation is performed on time domain data, so the resultant sound level does not represent any specific band of frequencies. To calculate Leq across a certain band, you must first filter the data to isolate the frequency band of interest. The example below uses the
Equivalent continuous A-weighted sound pressure level is a common measurement used in industry to characterize noise levels in loud environments. The result is expressed in dB(A), a weighted decibel scale that filters frequency components to roughly imitate the hearing profile of the human ear.
Products and Services: NI Sound and Vibration Measurement Suite
KnowledgeBase 207E3JLJ: Why Should I Use Decibels to Display My Data?
White Paper: Decibels
Report Date: 11/22/2006
Last Updated: 10/29/2014
Document ID: 43LD037E