Question about Sound Power Levels and measured Sound Pressure Levels in dB(A) -Acoustics Forum-Acoustic Fields Forum

Hey guys!

I’ve been trying to wrap my head around this question for a while and can’t seem to find any answers. Hopefully someone can help me out on this:

Let’s say you have two different noise sources. Let’s also say that the spectral content of these noise sources vastly differ.

For example, the first source is very bass-dominant, and the second source is very high-end dominant. Although their tonal balance differs, allow us to assume they have the same overall sound power level (for example, 89dBA). All spectral data is A-weighted.

Let’s say you are standing 1 metre away from each noise source with a microphone (and the noise sources are in exactly the same location). Assume you are in a free field, with no reflections. The first noise source plays, then the second noise source plays after that. Which sound would you measure as being louder, and why?

What factors will contribute to the difference in sound levels measured at the receiver point where you are standing ?

I was under the impression that if you had the overall sound power level of two different sources was the same, then the SPL at the measurement location (dBA) should also be the same, but when running this scenario in acoustic modeling software, the SPL values are not the same for the different sources.