At 12:45 PM 4/5/2003 -0800, you wrote:
>Marty
> I liked your inclusion of a superposition graph so
>much that I included it on my page.
>http://www.akwebb.com/gkweather/ambient/selfnoise.html
>
>Do you think these graphs have much use in comparing
>different microphones?
>
>As an old retired high school physics teacher, the
>discussion of transverse and longitudinal waves makes
>me want to break out the wave tanks and slinkys and do
>some demos.
>
>I'll resist the urge.
>
> Greg Kunkel
Greg:
Yours looks even better in that format. I was having transparency problems=
with my graphic program. But it does show that your ambient is always
higher than your self-noise, making the mic useful for recording whenever
you get close to a specific desired sound source. Yes, I think a field mic=
should definitely have some head-room to be effective, and it should show
well in such graphs.
When I taught Physics in HS, I made a pendulum set to demo wave
resonance. I had about 20 pendulums - washers on strings - all hanging
from the tile ceiling in a line about a foot apart. Each was slightly
longer than the previous neighbor. Along the top of each string, about 2 "=
from the fulcrum (push-pin), ran a transverse string parallel to the
ceiling, and attached lightly with tape to each pendulum it passed. At the=
end this traverse was tied in a loop around the big, adjustable, master
pendulum - big weight on heavy string. Hanging from a pulley at the top,
this one could be adjusted to any chosen length by pulling it in or letting=
it out. When you started the master big guy swinging, the motion was
gradually transferred to all the other (receptor) pendula, but only the one=
of the same length really picked up any energy, like a radio tuned to the
same frequency. Passersby seemed amazed.
my best regards,
Marty Michener
MIST Software Associates PO Box 269, Hollis, NH 03049
EnjoyBirds.com - Software that migrates with you. http://www.EnjoyBirds=
.com
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