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Original Message
RE: Outdoor Speakers Sound Degradation
Posted by tomservo on April 17, 2017 at 10:29:42:
Hi
I deal with loudspeakers, sound out doors at distances at work and can offer an explanation.
If you had a single very small driver, it would radiate as a "point source" and project a portion of a sphere forward. As you move away, the loudness falls off at the "inverse square law" or -6dB every time you double the distance. Also at high frequencies, there is air absorption which attenuates the high frequencies although at a hundred feet or less it is insignificant (a calculator below)
http://www.sengpielaudio.com/calculator-air.htm
The problem is that if one has more than one source in a loudspeaker, one has an interference pattern when they are both radiating and in loudspeakers, one manifestation is that the spectral balance and loudness changes with distance.
On a larger scale, this inherent multi-source interference pattern is what gives concert line arrays "that sound", variable spectrum based on location and a limited working distance, it isn't a loudness issue, it's more of a spectral and intelligibility issues.
So, in general outdoors when the weather is good, is a more benign environment for listening, especially at the scale of home stereo as there are NO room effects and it is surprising what one can do outdoors even at the scale of a football stadium.
What scale are you dealing with?