The Zipper

Other recordists have commented about unusual recordings of what sound like zippers. If this is a mimicked sound it would make sense in that one of the most often heard sounds in a campground at night is zippers on tents and sleeping bags. I had never recorded anything resembling this sound.

Early in May of 2013 my wife and I camped for ten days in Eastern Ohio. As it is early in the camping season most of the areas were sparsely populated with other campers. This particular night there was only one other unit within 300 yards of us and it was also a camper with no tents.

On reviewing my nights recording I found this unusual sound resembling a zipper.

Click here to listen to sound clip: Zipper 1

Waveform View

Spectral View

3 Responses to “The Zipper”

  1. Anthony Ciani says:

    The spectrum for that zipper has such pure and clean frequencies, I'd have to say it is a zipper. Also, there seems to be a bit of a resonance to it, so I should think it was a zipper on something taught.

    At night, sounds seem to be coming from closer than their sources actually are because a lot of the daytime white noise is gone, so that could have been from one of the other campsites. As I recall, some campers also have zippers on their exteriors for things like the pull-out beds or awnings, and often the covers of extra wheels and propane tanks have zippers. Maybe someone was playing with a zipper?

  2. stancourtney says:

    Whatever it was, it was within about 5 feet of my remote recorder.

  3. Anthony Ciani says:

    Interesting. I'm sure no known objects that could have made a zipper-like sound were so close to your recorder, but how was this close proximity determined?

    If it can be certain the source was within 5 feet, then insect activity cannot be ruled out.

    Also, bats send out a feeding buzz that has a repetition rate in the 100's of Hz, and sounds like a zipper (it gets faster and faster). Their calls are normally outside of the audible realm (20kHz to 90 kHz), but if the source was close, the bat calls could have provided enough impulse to heterodyne with the mechanical structure (diaphragm) of the mic or the compression algorithm or filters, or disperse through the mic and broaden into the audible range. The power spectrum is very intense at ~200 Hz, but otherwise very broad, like a dispersed pulse. Do you record at 90 kHz?

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