Sound Envelopes

[ReverseEntropy]

While the ideal loudspeaker emits a sphere of sound, many people picture the typical loudspeaker as emitting a cone of sound. But, I am trying to model outdoor mass notification systems, such as tornado warning systems. These look like a stack of pancakes on a pole and can emit 360 degrees in the horizontal plane* of the speakerstack...if not almost spherically around the speaker stack. So, before I press the vendor for more details, any clue what the sound envelope might look like for such a design?

*I know, a plane has no thickness while the speaker-stack does. But, the vendors claim 360-degree coverage...which may be emblished if they're trying to say constant dB-SPL at 360o.

Thanks in advance to all - for your thoughts on this.

 

[GregLocock]

In the horizontal plane I expect they are pretty much axissymmetric, in the vertical plane they will resemble the usual piston in a semi infinite baffle polar plot, which changes shape depending on the wavelength and the height of the array off the ground.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[IRstuff]

Doesn't that just depend on the actual construction and orientation of the speaker and its horn?

A speaker placed with its back down and projecting upwards against the outside of a horn would be capable of covering 360º uniformly. The faint picture in

http://www.federalwarningsystems.com/products.php?prodid=2

actually appears to show the speakers pointing downward.

TTFN

FAQ731-376

 

[VibeAC]

You should have the manufacturer provide you with vertical and horizontal polar plots for these speakers.

Andrew Gorton, MSc
Noise & Vibration Consultant

http://www.PapadimosGroup.com