I remember that exact article--probably was Popular Science (that was what we had at our house).
I was probably 10 or so at at the time--basically it was a series of tubes cut to wave length of the sound that was wanted to be captured.
The tubes were probably from 6" to about 40" inches in length. There where probably 8 or so tubes spiraled around the longest central tube--Microphone end was just a cut down aluminum funnel.
The lengths, I don't know if they were fundamental, 1/2, or 1/4 wave length tubes--Looking at
this website (Note: Chart units are in Feet) (since I am too lazy to do the calculations myself), I would guess the tubes were cut to fundamental frequencies and the tubes were probably an inch (or a bit bigger) in diameter.
Tubing, at that time, was probably made of metal--but I would probably give PVC tubing a shot and see how it works out.
Don't remember anything about the microphone itself.
If you can find a library with microfilm (or other archives) of old PopSci magazines, you can probably find the article pretty quickly (try ~1965-1974 first).
From doing a quick look around the Internet--it looks like people are using parabolic reflectors to build directional mikes these days (supposed to be better audio response).
I recently purchased a
pretty cheap (mono) microphone that does a pretty good job at picking out mid-range sounds (better than a video camera's microphone).
Overall, it is about 12" long, and probably too short to be considered a "real" shotgun microphone--but it does work pretty well for $50.
The "normal" mode seems to pickup sounds about as well as the human ear (normal levels) and the "tele" level does somewhat better (and is more directional). Normal mode sounds pretty nice (I use it for recording our children's concerts). Tele mode is less "warm" (I use this for their sporting events to hear the splashing of water and such) and can easily pickup the zoom motor noise on my old 8mm Sony video camera (also can hear a little bit of hiss during quiet moments). You have to be careful when handling the cable--it picks up any movement. I used a mono-to-stereo adapter for my camera to get even sound on both channels.
I would give this microphone a shot if you need some better recording outside and want something to "play with" (use in parabolic reflector and such).
-Bill
