Why The Greeks Could Hear Plays From The Back Row

Nature ^ | 3-23-2007 | Phhillip Ball

[aruanan]

In the first century BC the Roman authority on architecture, Vitruvius, implied that his predecessors knew very well how to design a theatre to emphasize the human voice. "By the rules of mathematics and the method of music," he wrote, "they sought to make the voices from the stage rise more clearly and sweetly to the spectators' ears... by the arrangement of theatres in accordance with the science of harmony, the ancients increased the power of the voice."

Gee, and to think they did it all without the glories of Muslim science and mathematics!

[Yardstick]

I don't know that I'm super qualified but I'll take a stab at your question.

It seems intuitive that the wind would blow sound to us, like smells.

The difference being, of course, that while wind is a carrier of smells, it is a medium for sound. In the first case it provides transportation for smell particles, while in the latter it allows propagation of sound waves. These are two different things, so the intuition is mistaken. You can really see the difference in the two if you think about what happens when the air is perfectly still. In that case, the smell goes nowhere (well, it does disperse by diffusion but that's a different process) whereas sound will travel at the speed of sound.

However, it is far from obvious when you look at the physics...

Yep, and in fact I think the physics is pretty clear that wind would have a negligable effect on the loudness experienced by the listener, since as you point out

Sound travels at around 1100 ft/sec whereas a good breeze is 30 ft/sec.

I think the bottom line is that when the article says that

Later writers have speculated that the excellent acoustics of Epidaurus, built in the fourth century BC, might be due to the prevailing direction of the wind...

you pretty much have to conclude that those writers were mistaken in their speculations.

But here's my own speculation -- I think the wind, if it did have an effect, would be to slightly change pitch of the sound rather than its volume.

[shuckmaster]

It has to do with a little trick with how acoustics are affected by height and angle. On my job, I can walk around on a hillside that overlooks a dock and I've discovered their are certain places on the hill where I can position myself and clearly hear the normal volume conversation of people on a small area of the dock approx 60-80 yards away. If either me or the talkers walk away from those positions, the voice reception is lost.

[Joe 6-pack]

"Because their hearing hadn't been destroyed by headphones and industrial sound?

I'm thinking that sound waves travel better in cooler, denser air, and this was before global warming.

[expatpat]

Thanks for your response and input. I hazard an explanation in post #10, which you might read.

[MinuteGal]

The variety of knowledge among so many of you freepers astounds me again and again.

Your willingness to share information, educated opinions and career/avocation experiences is admirable beyond any words of praise I can summon.

Leni

[blam]

"The variety of knowledge among so many of you freepers astounds me again and again."

Thanks and I agree...I learn so much. There are some smart FReepers here.

[-=SoylentSquirrel=-]

Agreed. Ever since discovering FR I are much smarter.

[MinuteGal]

LOL!

Leni

[FlyVet]

But here's my own speculation -- I think the wind, if it did have an effect, would be to slightly change pitch of the sound rather than its volume.

I know nothing about physics, but there is more to it than that I think. There is a gun range a mile south of my home. When the wind is blowing from the south, the sound of the gunshots is significantly louder. I can hear them loud and clear indoors with all my doors and windows closed. I does seem odd that a 20 mph breeze, for instance, would make that much difference, but it does.

[SunkenCiv]

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