Getting esoteric on infrasound Re: [sdiy]

[KA4HJH]

>Getting esoteric on infrasound

Feeling fuzzy so I have no idea what I'm saying. Don't blame me if this is
all wrong--I'm not even proofreading it.


>So at what point is it no longer sound?
>Is that when the movement of air is exchanged for the movement of earth?

Depends on your definition of "sound". Arbitrary definitions will set an
equally arbitrary frequency at which it becomes "sub-sonic" but even then
the air is still moving. Then you have to have some device like a barometer
to measure the relatively slow changes in air pressure. And once you get to
a low enough frequency it takes a LOT of energy to move enough air to make
a wave propagate any significant distance. At some point it's not sound,
it's weather.

One might ask the similar question at what point does AC become DC? When
the current stops changing, of course. Technically there's no such thing as
DC unless you're talking about a never changing current that has always
existed and will exist forever. But the attention-span-limited human brain
puts arbitrary limits on things like that otherwise it can't cope.

Things happen in this universe all the time on scales that are practically
imperceptible, either because they're too slow for the human brain and its
sensory array or they're too fast.

>
>What drastic changes occur at this threshold?

None. There is no "threshold" in this context.


>Throbbing gristle indeed!

Merely listening to Second Annual Report has been know to induce nightmares.


>A parallel of this can be found in transonic ballistics, the point in a
>bullet's trajectory where it falls below the speed of sound.
>At this moment the trajectory actually makes drastic changes.

Here there IS a drastic threshold.


>At what point does it become evil? and when not?
>and what is the transvibrational threshold - where vibration of the Earth
>changes to that of... (what)?
>The periodic table of the elements? or the duration of time we call a
>century?

Some would say that when you reach the level of Quantum Mechanics it
becomes "evil"--or at least very hard to accept. "Reality" as we are
familiar with it (i.e., Newtonian mechanics) ceases to exist.
-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

"It gets calls when nothing else works"--Walter Eugene Scott, PhD,
explaining somewhat facetiously why a "TV preacher" was smoking a cigar.