The View Up Here

Random scribblings about kites, photography, machining, and anything else

Weatherproof Recording Box – Part 2

Posted by Tom Benedict on 02/06/2017

A little while back I wrote about a weatherproof recording box I’d built so that I could do drop-and-recover field recording without having to care quite so much about the weather. The design had a couple of shortcomings, most of which I’ve been able to address. Since then I had the chance to take the revised box out into the field and put it through its paces. I’m happy with how it performed.

The two biggest issues I had with the first revision of the box were the heating problem I mentioned at the tail end of that article and the fact that with the connectors I was using, I couldn’t actually plug all four channels into my recorder and still have it fit in the box. I had a couple of minor issues as well, including the fact that the lid on the weatherproof outlet cover rattles. Here are all the changes I made to address these problems:

I fixed the rattle in the outlet cover with small snippets of weatherstripping. Nothing fancy, just adding enough spring to take out any tendency to rattle in the wind.

I also added strips of industrial strength Velcro to either side of the box. This makes it easy to use the box as a baffle and mount omnis on either side like tree ears. I’m not entirely happy with how this sounds, though, since the box represents a much harder boundary than tree bark does.

The way I solved the connector issue was to swap out all the Neutrik XLR plugs for low profile connectors from Cable Techniques. Redco Audio sells these for about $15US. They come with black caps, but Cable Techniques makes color caps for the connectors as well, so I was able to maintain the color coordination between the outside panel and the inside connectors.

Low Profile Plugs

While I was at it I bought a right-angle USB cable for the battery pack. In 20/20 hindsight I wish I’d bought one with a right angle connector at both ends instead of just at the micro-USB end. But at this point it’s just a nit-pick. The cable I got works fine.

Right Angle USB

With those two changes, everything now fits in the box with all the foam panels installed.

Everything Fits

Which brings me to the second major modification: In an edit to the last article I said that I’d tested everything with a temperature logger, and in a 21C room the air temperature inside the box had risen to 34C after eight hours of operation. What I didn’t take into account is that the battery and recorder were considerably warmer than the air in the box. The operating range on my DR-70D is 0C-40C. I wasn’t comfortable running it that close to the limit.

Thermal Pad
The foam panels in the box are all removable. They just wedge into place. So I pulled the two side panels and installed thermal pads. Thermal pads are made out of silicone that’s had thermally conductive additives mixed in. They’re graded by their rate of heat transfer. The pads I bought have a decent transfer rate, but aren’t up into exotic territory. (I got mine off of Amazon.) As it turns out they’re probably overkill for the job, but I’d rather err on the side of too cool than not cool enough.

Everything Heat Sinked

With both pads installed and everything loaded into the box, a small block of closed cell foam acts like a spring to keep the battery and the recorder pressed up against their respective pads.

Weatherproof Recording Box in the Field

Last weekend I took it out to an old cane haul road on the Hamakua Coast to record coqui frogs. Unfortunately the road was blocked off about a mile from where I wanted to record, so I had to set in a different location along the road. It looks like logging operations are about to start out there, so this may be the last time I get to record at that location. (The box is weatherproof, but it won’t stop a bulldozer!)

I had some issues with moisture causing noise on the mics early on in the evening, but overall the session went well. I used my SASS with EM-172 capsules for this. EM-172s aren’t typically all that sensitive to humidity, so I’m looking into why the mics glitched. So far I haven’t been able to reproduce it, but I might spend some time monitoring the next time I use this box just so I can hear if it’s happening again.

Meanwhile, here’s a long(ish) track from the test. It covers the sunset transition from primarily birdsong and insects to the coqui frogs dominating the soundscape. And there’s the occasional cow. (I really love the way cow calls reverberate through eucalyptus trees.)

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One Response to “Weatherproof Recording Box – Part 2”

  1. […] I came up with a fix for this and the connector issue, which I describe in the second part of this article: Weatherproof Recording Box – Part 2. […]

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