Like I said, I don't have access right now to the info.
I do know that there have been many concerts done with less than the full compliment of 24 boxes per side (typically 18 or 19 MLA and a single MLA-D) with coverage out to 250 meters and drop off created at 300 meters to avoid noise complaints.
I will try to find the info that I have on the other coverage. It was between 700' and 900' if I am remembering correctly although my memory is not what it used to be. :-)
Lee
It is the freq above 4K that is affected the most by air absorption.
Sure-there is plenty of sound below that. But once you get above and actually MEASURE-you QUICKLY realize that there is a "problem".
I remember measuring my first stadium (BYU).
We had a mic at the far seats-about 700' in this case- and the response was rolling off on the top end.
So we boost a little at 10K. Nothing happened. We boosted some more-nothing happened. I did not want to add more than 12dB of boost. The response was so low on the screen (as compared to the lower part of the response) we could not even see it.
This was using a TEF 20.
That night at the hotel I did some research on air absorption and realized there was NO amount of boosting that was going to get the HF response up at those seats.
That is when I said to my self-we need a "real" super tweeter.
And even then all we picked up was an octave.
But considering that is higher than most systems go anyway-I guess it is fine.
When you actually MEASURE at those distances-you realize how "tall the mountain" is you are looking at.
But casual listening will not tell you that.
Simply saying "I have highs out that far" does not mean anything unless you attach some REAL numbers to it.
Of course the "excuse" that many people like to use is "Well your brain is used to the HF rolling off at a distance-so it is OK">
OK-Let's "buy" that argument for a second.
BUT LOOK at the VIDEO screen! They make it VERY LARGE so as to move you close to it. In REALITY, a body on the screen would be very small and you could not see it at that distance.
So you would expect the sound to be "far away" as well.
But since they have moved the image closer to you-should not the sound be the same?
Should not the objective of any sound system be to provide the same experience for everybody? Or as close as we can?
That INCLUDES full freq response as best as possible-along with the same SPL.
YES- there will be exceptions and variances, that "should" be the goal.
I have a good number of "stories" that I can't tell (or maybe I could if I left off manufacturers names-I'm not sure on that one) about ACTUAL "like" experiences of line arrays and long distances vs a single source approach.
If people are interested in that-then I need to get moderators approval first. But they would be interesting reading.