Oop!
On Mon, 19 Nov 2007 22:41:22 -0500, "soundhaspriority"
wrote:
[snip]
However, the 8 foot height provides resonances at multiples of 60Hz,
which I am most familiar with in the context of bass problems. Can you
supply a link to a technical backgrounder?
Oops! The modes are 60, 180, 300, 420...
This is a suprisingly difficult subject, because the whole
idea of room modes is so often misunderstood, or at least
mis-interpreted.
Parallel surfaces can support a "mode" at a half wavelength,
and strongly at integral multiples of reciprocals. So an
8 foot ceiling (the fate of we peasants in the land of
sheetrock, also called drywall in Old America) supports
a mode at 1130 ft/sec divided by 8 feet, or about 140
compressions and rarefaction cycles per second. And
integral multiples of 140. And some others at integral
multiples of half of all these numbers.
The real meaning of "modes" requires more poetry than I'm
capable of. Others will do much better. Perhaps most
suprising is that there *isn't* a simple predictable
universal cancellation or reinforcement.
What's interesting to me is how unintuitive such a seemingly
physical thing really is. It's not that it's voodoo; it's
that it's deeper than that.
Pardon all the dangling whatsistits, and much thanks as always,
Chris Hornbeck
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