Homemade Outdoor Microphone

By Jason Goldring

I wanted to experiment with different outdoor microphone setups to obtain the best possible sound and weather resistance without breaking the bank. Call it a "mic on a budget" if you will, what I came up with was surprisingly easy to make and actually performs quite well.

By no means should you take these construction tips as the only way to construct this mic. Experimentation is encouraged and if you come up with something really interesting or would like to comment about your project, improvements, etc feel free to drop me a line or better still, leave your comments!

Basically there are 3 details of this microphone that I felt were “Key” elements which needed to be addressed.

First and foremost was the weather and water resistance. The idea is that if water entered the enclosure, the microphone would not get wet and the enclosure would be self draining. Because of the raised design where the mic element is raised from the mouth of the bottle on a post, even if the bottle began to hold liquid, it would be still take a little while for the bottle to fill to a critical level, by that time, you would have probably already attended to the microphone. (Insects come to mind such as spiders and they have a nasty tendency of crawling into and plugging up small holes with cobwebs. The second detail was the actual audio quality of the setup. I knew that the sensitivity of the mic would be reduced when placed in the enclosure but that was to be expected. More about this a little later. This is simply an experiment, the audio quality certainly does not replace the setups that I have used in the past, but merely offers an opportunity to be creative.  The third detail was the ability to reduce or almost eliminate wind noise. And did I ever put that to the test. I must say I was quite impressed with the ability to reduce wind noise.

Here is a list of items I used to construct the microphone. Again, experiment and deviate if you so desire, that’s what makes stuff like this evolve into bigger and better setups!

I originally wanted to use a round bottle such as a V8 juice bottle; however during my experimentation I found that the noise cancelling capabilities of the bottle (particularly wind) were not as good as a square type of bottle. Evaluating sound samples from the V8 bottle showed that the wind entering the enclosure actually creates a sort of “vortex” effect which was not desirable. The 45 degree angles used in the Ocean Spray bottle pretty much eliminated any vortex that may be created in the presence of high winds.

First, we take the juice bottle and rinse it out good, removing the label from it.

Next, we create the microphone base from the cap of the bottle and the pen.

In the picture you will notice that I made two small holes in the cap and that there is a bamboo stick attached to the center of the cap, this was later changed to a papermate pen enclosure for durability. A small screw was used to hold the pen case to the center of the cap.

Next, I took the bottle and began making the sound collection flaps

and the microphone cord hole. The sound collection flaps are made

by using a small X-Acto knife and cutting. The best way I can describe

the sound holes is by cutting an "Upside Down" U on an angle across

working down the surface of the bottle. On each "wide side" of the

bottle there are three flaps cut, on the narrow sides there are only

two. I modified this picture of an orange juice bottle to try and visually

give you an idea of what I am referring to.

***SPECIAL NOTE*** We are not cutting out square holes, we are bending "in" the plastics flaps

that we have created.

Once the flaps have been cut, we bend in the flaps or "tabs" so that a good portion of the

hole is exposed.

Next, we make a hole to fit the microphone cable through, I did this about 2 inches up from the mouth of the bottle as shown.

The next step is to attach the microphone to the pen assembly, and in order to prevent vibrations from being picked up by the mic, we wrap a small elastic band around the top of the pen, then we attach the body of the microphone to the top of the pen with another elastic. Basically the first elastic acts as a vibration damper.

One important note - Once you have fastened the mic to the pen case, you should also fasten the mic cable to the pen case as well, but leave a little slack. This will prevent slight movements from causing the cable to strike the bottle or the pen casing, causing the sound to be recorded.

Once the microphone is attached to the pen, we insert the assembly into the bottle and fasten the lid. Below is a picture of the "almost completed" setup.

Finally, we place the dollar store winter toque over the assembly to act as a wind guard and to help resist the elements. You may choose to place an elastic band around the entire assembly to help prevent the hat from blowing off the bottle.

Pretty simple, eh?

I did not put silicone around the mic cable leaving the bottle until I was sure how much slack I needed. Afterwards, I sealed it up and voila!

____________________________________________________________________

Visit Jason's Blogsite: The Ticking Mind to read this article