Audio Field Recorders

These are recording units that we developed to leave in research areas overnight. We refer to them as "Drop Boxes" as the first ones that we used consisted of plastic refrigerator boxes, which have since been replaced by the waterproof hanging platic containers that you see on this page. These are easier to setup and are less conspicuous and take up less space in your backpack. The idea that led us to use these is that we felt like we needed a wide area monitored for return vocals during call blasting. On any given night we may place up to a dozen of these arrayed throughout the research area which allows for Bioacustical canvassing of an area of several square miles. Even though we are using large parabolic dishes we felt that it might be beneficial to have a set of listening posts spread out over a large area in case we had something respond that was a good distance away, say over 300yds. We spread these out over the target area with separations of distance being anywhere from 100yds to as much as a couple of miles. In addition, since most of the time we terminate our operations between 1 and 3AM these will continue to monitor the area for the remainder of the night for anything that would be out of the ordinary for the local fauna. As you will notice in the pictures the recorders generally use a single AAA battery, this works ok in warm weather however cold weather drains the AAA's quickly lasting 6-7hrs. As a result we have setup a AA Cell battery holder to bypass the AAA so that we get the full recording length at high quality, which for most of the Olympus models is now in excess of 17 hours.

In case you are interested in replicating these for your own research efforts we recommend any of the following Olympus Digital Voice Recorders: Olympus DS-30, DS-40, DS-50, WS-310M, WS-311M, WS-320M, WS-321M, WS-210S, WS-400S, WS-500M. You should be able to find most or all of these on Ebay. These have acceptable sound quality with CD quality sampling rate and are cheap enough that you can afford to have several and if one disappears you aren't out too much. You can buy and use more expensive units that have higher sound quality and record with more than the 64kbps that the above models use if you don't mind being out the extra money should you lose one.

If you review the recordings that we have posted, many of those came from using the Drop Boxes. This includes those on our Walkup Recordings page. These recordings are a side benefit from putting these out, we didn't envision things finding the recorders and walking up to investigate the hardware, however, we feel the results speak for themselves. Being that this is only audio it will not stand as definite proof of the presence of an "unknown or undocumented" species of primate in the area, however, we do feel that they are highly suggestive of that possiblity. Most of these recordings were captured on private property, in some cases in very cold weather, late at night in very remote areas with no known human presence or activty. Due to the results that we have and are getting we are now implementing a setup at each recording station that includes the audio recorder a game camera and bait of various types to try and get the elusive picture. The audio will reveal if we had any visitors during the night.

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The original dropbox, plastic food container, we have replaced them with these hanging containers.

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We have created a bypass system to extend the battery life beyond the regular AAA battery.

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This demonstrates how we hang these in trees, this one has been camo taped.

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