Average sound power level

Professional Definition

The average sound power level is the sound power level determined according to a formula that takes into account the energy average of partial values from specified measurement points on the measurement surface or within a specified time interval.

In engineering practice, this means that we do not take a simple arithmetic average of values expressed in decibels. Due to the logarithmic nature of the scale, calculations must be based on summing energy (logarithmic average). This is a key parameter used for objective assessment of noise emission by devices, theoretically independent of the distance from the source and the acoustic properties of the room in which the measurement is taken.

Acoustics in Simple Words

Imagine a traditional 100-watt light bulb hanging in the middle of a room. Regardless of whether you approach it closely or stand in a distant corner, the bulb still produces and emits the same 100 watts of energy – this is its constant power. However, the light may not spread evenly in all directions; in one spot, the fixture casts a shadow, while in another, the glass is clearer and it is brighter.

To fairly determine how much light the bulb “gives,” you would need to measure the brightness from every side around it and calculate a specific average from that. The same goes for the noise of the machine: the average sound power level is the result of such a “surrounding” measurement. It tells us about the total noise strength generated by the device, “smoothing out” the differences arising from, for example, the engine being louder at the back than at the front of the casing.

Summary

The average sound power level is a standardized quantity that defines the total emission of sound energy by a source, calculated based on multiple measurement points. It is a parameter essential for the certification of machines (e.g., CE marking) and for creating acoustic maps in the industry.