Question about Sound Power Levels and measured Sound Pressure Levels in dB(A)

[Leebanana]

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 ?

 

[GregLocock]

Assuming you are in the free field (not near field) and cancellation etc is not an issue then they should measure the same.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[hydtools]

If both sounds have the same mid frequency content the measurements should be the same. A-weighting attenuates the low and high frequencies.

Ted