A site dedicated to the review and analysis of potential sasquatch vocalizations, Sasquatch Bioacoustic combines techniques from the domains of intelligence collection, audio analysis and bioacoustic studies to examine the evidence of sasquatch through their vocalizations. ~Monongahela

Thursday, May 2, 2013

My Long Duration Audio Recorder

For some time I've planned to share a few photos of the long-duration recorders I use in the field to collect sasquatch vocalizations. I've built three of these, and this evening I was preparing one for a new deployment, so I took the time and captured the pics below.


These are the guts of the system. On the right you can see the TASCAM DR-03 recorder which can be programmed to start and stop at specific times, and draws external power through its USB port. I've exposed the recorder for this photo, but during deployment it will be tucked into a pocket in the foam it's resting on. Notice the red tape on the right edge of the recorder. It helps secure the external mic and USB power supply cord in place, should the recorder receive any rough handling. (One of my recorders has been mauled by a bear, twice, and continued to record.)

This view shows the recorder tucked into place, in a pocket in the foam (lower right corner), surrounded by a plastic bag (to improve moisture resistance). In the center of the photo you see the power supply, a small, 12 volt lead acid battery. This is a little larger than the size you often see on motor cycles. The large alligator clips connect the battery terminals to a cigarette lighter style power plug. This is out of view in the foam pocket in the lower left corner of the photo. Inserted into that plug is a USB power plug, the type you use in your car to charge your cell phone. Connected to that USB power plug is a USB power cord, which you see emerging from the foam pocket. That cord runs around to the recorder to provide it with external power.

Here's the system all buttoned up and ready to go. This case is made by Plano and easily found in many sporting goods stores. I've added a bit of duct tape to the outside because I overstuffed the foam, and it causes one side to bulge a bit. Normally this isn't necessary and the case seals very well when closed. In the field I'll add some cordage to the handle and tie the device to a tree. This makes it more difficult for a bear to pick it up and carry it away (something that has happened to another of my recorders).

Finally, in this view, you can see one of the two stereo microphones built into the case (the second is on the opposite end, out of view). These sensitive mics are held tightly in place with grommets. They are recessed a bit to shield them from direct moisture, and the upper edge of the case provides additional protection from precipitation as well. This configuration gives very good stereo separation in the audio the recorder captures and that's important to discerning which direction a vocalizer is located, relative to the recorder.