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KAS – aka In Over My Head (again)

Posted by Tom Benedict on 15/06/2015

Some years ago I was hot on the idea of launching a high altitude balloon, festooned with cameras I’d used for doing kite aerial photography. I still have some of the bits and pieces from the balloon payload I never built, including a really neat little styrofoam cooler a co-worker was throwing out. In the process I watched a ton of videos from high altitude balloons (HABs), but none of them struck me like one I found from a launch in Florida. Unfortunately I haven’t been able to find this video again, or I’d share it here. What set it apart from the others was the lack of a music sound track. Instead, it used the audio from the camera. What I heard blew me away.

The balloon was launched from a city park. In the video you can hear all the normal sounds of a park: kids playing, dogs barking, the launch team talking amongst themselves. Just after launch you continue to hear these things, but gradually they die out, to be replaced by sounds of nearby traffic. Eventually the traffic dies out, leaving only a siren wailing in the distance. Finally the only sound left is that of an airplane flying well below the balloon, which at that point is over 50,000′ above the ground. After that, nothing.

I never did build a HAB of my own, but that video made me fall in love with the idea of recording sound from the air. I tried using the microphones on my KAP cameras, but the on-camera audio, even on a camera like a Canon T2i, is pretty poor. The microphones are tiny, the sound is hissy, there’ s no wind protection, and the T2i has automatic gain control you can’t turn off. (Later models like the T5i have this as a menu setting. Good move, Canon!) A few years later when I got into doing video on the ground with my T2i, I got a separate audio recorder for just this reason. It didn’t take long before I flew the recorder on a kite, but the sound still wasn’t great. No fault of the recorder, mind you. It worked perfectly. But I could hear the rig servos, the Picavet pulleys, line sing, and everything else going on on the KAP rig. I gave it up as a bad idea until I could think about it more.

So I thought about it. And I researched it. And I started learning the intricacies of field recording. I hit on Paul Virostek’s blog and bought a copy of his first book, “Field Recording: From Research to Wrap”. If you’re interested in sound and field recording, I highly recommend Paul’s book. He doesn’t start with the assumption that you have to own the latest, greatest, most expensive equipment. He starts with the assumption that you want to record sound. It’s a good place to start.

I haven’t had a lot of time to pursue my hobbies recently. I spent the last nine days painting and re-flooring my house, and in all that time I picked up a camera only once: to photograph the new floor. But Saturday morning I found myself in Kailua-Kona with time on my hands before my next appointment. “Aha!” I thought, “I’ll go record the surf at the Old Airport Park!” I grabbed my field recording gear and headed that way.

What followed was a comedy of errors worthy of a Marx Brothers movie. I set up to record surf, only to hear a persistent helicopter sound. I looked up to see a whole slew of skydivers with US Army canopies, and a Chinook flying overhead. The skydivers were landing in the park. One of the points Paul makes over and over in his book is that field recordists need to approach things in terms of serendipity rather than ruined opportunity. I couldn’t record the surf because of the helicopter, but I could record a helicopter!

I ran over to the landing area in time to catch it. But the mics on my little field recorder were overwhelmed. By the time I’d dumped the gain enough not to clip, the helicopter had landed and the event was over. I stuck around for takeoff, only to find I’d accidentally paused the recording until the helicopter was out of range.

So I went back to the surf, only to find the skydivers had jumped again, and the Chinook was coming back down. Back to the landing field!

This time I got a better recording of the helicopter, but the crowd noise was a little overwhelming and I still clipped. I got a good recording of the takeoff, though. Back to the surf!

I finally got a good surf sequence, but at the tail end a large set of waves came in and swamped my location. I grabbed my gear before it got splashed, only to have my windjammer fall off the end of my recorder and into the water. It looked like a little floating hairball. I fished it out, rinsed it off, and called it a day of lessons learned. Two days later it’s still damp. One more lesson learned: don’t let these things get wet!

I’m still a fair way from being ready to try kite aerial sound again, but I’m getting closer. I know what went wrong with my earlier sessions. I  know I want to wire in the audio channel on my video transmitter and set up my ground unit with a headphone jack. I also want to test all my gear in a studio box to see if I’m picking up RF hum from the transmitter. I now have real motivation to change from Picavet to pendulum suspension for the rig. I know I need line dampers to take out line sing, even though the KAP community moved away from them years ago. The list is long.

After that it’s a question of building a KAS rig that’ll give me the aerial sound I want. Right now I’m looking at building a variation of Curt Olson’s Olson Wing using EM-172 capsules, which I found from Zach Poff’s article. I’ve got other supplies from an earlier attempt to build windjammers for a borrowed pair of lavalier mics that should let me cut down the wind noise as well. I’m still not sure what I’ll use all this for, but it should be fun.

– Tom




2 Responses to “KAS – aka In Over My Head (again)”

  1. Nice entry Tom. KAS has been overlooked but has great potential- adds to record of height in an almost subliminal way. Calls to mind a recent clip from Nicholas Chorier you get to hear the sea, snatches of conversation traffic’s lovely.:

  2. Tom Benedict said

    I’m eager to try this again in the air. That clip Nicolas Chorier did to demonstrate his new rig was another good prod in the butt for me to get back to this. I’ve got some technical issues to sort out before I’m 100% happy, though.

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