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4.9 KiB
Plaintext
1 line
4.9 KiB
Plaintext
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%% =================================== %%
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%% HOW TO CONSTRUCT A RIFLE MICROPHONE %%
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%% =================================== %%
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%% Another file from Omnipotent, Incorporated %%
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%% %%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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This is a most unusual project; we are going to mount a sensitive
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microphone behind a series of acoustic wave guides and hope for the best.
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Actually, our wave guides are aluminum tubes cut to resonate at frequencies
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near the human voice range. This arrangement also serves to make the unit
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highly directional as sound other than that arriving at the mouth of the tubes
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arrives at the mic in an out-of-phase condition and cancels itself out.
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With this easily constructed device it is possible (under ideal
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conditions) to pick up conversations several HUNDRED feet away, in fact,
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reports of recording conversations up to 30 yards away THROUGH A CLOSED WINDOW
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have been made...
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The device is quite easy to construct: First get together the following
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materials:
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[1] 56' of 3/8" outside diameter aluminum tubing (hardware stores)
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[2] 1 sensitive amplifier with operating paraphenalia
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[3] 1 sensitive microphone element -- use either a good condenser or a
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crystal, as their outputs tend to be a bit higher than their dynamic
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counterparts.
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[4] 1 funnel
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[5] Assorted small hardware
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Cut the tubing into 37 pieces ranging from 1" through 36" in one inch
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divisions. Now bundle them together symmetrically with one end flush (as
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shown). As you assemble them, blue them together in several places to assure
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they remain in the state you have put them in (were it only so easy with
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people...).
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OOO
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OOOOO
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OOOOOOO
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OOOOOOOOO
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OOOOOOOOO
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OOOOOOOOO
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OOOOOOO
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OOOOO
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OOO
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Flush ends of tubes
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Take the funnel and fit it around the flush end of the tube bundle. Being
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astute enough to read this, I am sure you will notice the tubes do not exactly
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fit into the funnel. At this realization, take a small hammer and beat the
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funnel to nearly as possible. Now fill the remaining spaces with a good rubber
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based caulking compound.
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The microphone element is placed in the neck of the funnel (with a rubber
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grommet if it is small enough to fit up into the neck -- otherwise set it into
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the other end of the neck before caulking the tubing in place). Glue the mic
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into place and caulk any air space around it.
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Run the microphone wires out the neck of the funnel, glue in place, and
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also caulk to give it a closed, fairly air invincible seal around the entire
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unti. If you really feel up to it, fiberglass resin can be used instead of
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caulking compound.
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m ###\
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i ### \
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c ### \
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### \_________#
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e ### #______ wire
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l => ### funnel #
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e ### _________#
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m ### / ^
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e ### / grommet
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n ### /
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t ###/
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Run the output wires to your amplifier and place the entire unit on some
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sort of support, a camera tripod being ideal. (Need I remind you to check
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matching impedances?). The unit should be aimed at the subject and then panned
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about for maximum volume (sound does not travel in a straight line, but may
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vary with wind, etc).
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If wind noise overrides your target noise you can place a piece of
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cheesecloth across the end of the unit. If a particularly difficult noise
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interferes with your pick-up you can often plug up the tube(s) carrying this
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noise with a cork.
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Good hunting, avoid paranoid people who may feel your rifle mic more than
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resembles the real thing...
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Coming soon from Omnipotent:
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=-=-=-=-=-=-=-=-=-=-=-=-=-=
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THE BLITZ BOX!
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~~~~~~~~~~~~~~
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This will keep someone connected to your phone line for as long as you
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want. Annoy your friends. It has endless applications. WATCH FOR IT SOON!
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