This is a ridiculously easy way to build a parabolic microphone using dollar store items. You’ll attract lots of attention walking around in public with this rig. I usually welcome the inquiries, and let people listen to what I’m doing. Kids especially love it.
Microphone, small (1) I used RadioShack's discontinued Stereo Hands-Free Tie-Pin Microphone (#33-3028), but any decent small microphone will work. Dollar store purists can instead use earbud headphones as a microphone.
Cover 1 gore of the umbrella near the center with a trapezoidal piece of the gaffer’s tape. Cut a small X-shaped incision through the tape and umbrella; this will be the reinforced hole that the microphone wire will pass through.
Remove the paint roller’s plastic caps and wire frame. Push the shaft through the hole in the top of the umbrella, so that it protrudes 6" underneath. Leave ½" of clearance between the outer surface of the umbrella and the bend of the handle.
Just above the umbrella’s top knob, wrap a length of tape around the shaft and ring it with a cable tie pulled tight. Wrap the the shaft with more tape, to provide a gripping surface for the microphone.
You want to place the microphone at the focal point of the reflector, but realize that this is a plastic umbrella, not a perfect parabola. So this “point” will be more of a semifocal blur. Here are 3 ways to position the mic, in decreasing order of complexity:
Point a laser at different points on the inside of the umbrella from a distance of about 20 feet directly in front of the unit. Mark where it reflects onto the shaft to find the general region of focus.
Plug the mic into a recording device, put on some headphones, and point it toward a ticking clock some distance away. Move the microphone along the shaft until you get the loudest sound.
Just take my word for it, and position the mic about 3" from the inside surface of the umbrella.
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