How to make underwater recordings

When I started thinking about Containers, my audio documentary about global shipping, capitalism, and technology, I started spending a lot of time at Middle Harbor Shoreline Park, a thin sliver of a place pinned between the Bay and the Oakland International Container Terminal.

And it started to dawn on me that I could get really, really close to ships. Like maybe 30 feet. Check it out. You can go riiiight up to the fencethere.

And on top of that, you can access the water if you scramble down some slippery rocks. You see fishermen down there catching god-knows-what in the shipping channel. It’s pretty deep, roughly 50 feet since they dredged it a few years back.

You also see cute couples taking Instagrams together and longshoremen sucking down Marlboros and kind of sad people sitting in their cars staring out at the water and teenagers getting stoned and a few Latin guys who play soccer in a torn-up field right on the water, usually as the sun sets behind them and the city, the whole scene brilliant orange. Basically it is heaven is what I am saying.

Anyway, because you can get close to the water right where ships are moving, it meant that I could make underwater recordings of that process. All I needed was a hydrophone. Kai Ryssdal (yes that one!) suggested that I just put a condom on a regular microphone. Apparently this is a thing radio people do. But I needed the microphone deeper out into the Bay and I wasn’t sure a prophylactic-wrapped mic was gonna cut it.

At first I thought I could build my own hydrophone. Scientists seem to do it regularly. NOAA even has a guide. But then radio producer Lu Olkowski pointed me to the Dolphin Ear. It’s basically this contact microphone set on a huge long cord that plugs right into your standard XLR jacks on your digital audio recorder. They make them in Iceland and market them as a way to listen to underwater mammals. I ponied up the money and waited for the package to arrive from Reykjavik.

When it finally did, I realized I would have a logistical problem. The microphone is small. It’s like the size of a big orange slice and so it wasn’t the kind of thing you could just toss easily, especially as it was attached to the this thick cord. How was I going to get it into the water?

I went down to Middle Harbor Shoreline park and started practicing tossing the damn thing like a lasso. It is not easy. I considered getting a long fishing pole and taping the cord to it. But eventually, I just climbed down the rocks and almost into the water, then sent it maybe 10 feet out ahead of me into the shipping channel. And insantly, I could hear ships running the channel quite clearly. Victory!

What I really wanted to hearwas tugboats working a ship, pulling it off the dock. And as luck would have it, one day I was hanging around the park and several tugs came in to move a ship called the Cosco Excellence.

It was a beautiful evening. The lights on the ships glowed in the gloaming. And I had both my hydrophone in the water and a regular old mic recording the action. Monitoring things, I could hear the water in my left ear and the air in my right. It was disorienting and mesmerizing in equal parts. The part of the move that I captured really only took about 20minutes, but when I pulled my headphones off, I felt like I’d emerged from a cocoon.

Here’s the topside recording I made that night:

And here’s the underwater action:

If there’s one thing microphones teach you, it’s that the way our ears hear is but one way to process the waves on this earth. There are hidden dimensions of experience available if you’re willing to tune to a different frequency.

After that, Olkowski convinced me that I needed to get myself on a tugboat, so that I could dangle the microphone into the water and capture the slugging at close range. So I did and that experience became the core of Episode 3. So, go listen to that or you can read an annotated transcript here on Medium.

Oh, and back when I bought the hydrophone, I promised that I’d lend it out to anyone who had an interesting idea for an underwater recording. So feel free to take me up on that.