Available Tuesday, Oct. 13th

DESCRIPTION: 

I first learned about VLF recording back in grad school in 2013. It's this nerdy niche of radio enthusiasts with a lot of overlap with the ham radio community.

VLF stands for very low frequency radio waves, which basically means radio waves that are 20 hertz to 20,000 hertz. That's very low for a radio wave, which are generally in the megahertz or higher range. But because the radio wave is in the range of our hearing, you can translate the radio wave into something that you actually hear.
These VLF antennas can pick up electromagnetic storms in the atmosphere. A lot of these are caused by distant thunderstorms. When the lightning strikes, it actually creates a radio wave that bounces between the different layers of the atmosphere. That can be heard as something called a sferic or a whistler, and that's one of the more common VLF sounds.

But that wasn't my goal in Finland. I was aiming to record the sounds of the Northern Lights. The particles shooting out of the sun that hit our magnetosphere and create the visually stunning display of the Northern Lights also put off radio waves that are in this same spectrum. So you can hear pops, crackles, resonant noise and potentially other phenomena. And that was my goal in Finland.

But before I could record in Finland, I had to go through 10 years of failed attempts and iterations.

I first found a sound artist that was building these, and he taught me how to build a basic DIY VLF receiver, which is a giant spool of copper wire. This spool has to be a certain diameter and number of spins in order to pick up the frequencies I want. It looks like a big hula hoop.

The first attempt at recording VLF was on a 2015 cross-country bicycle trip where I rode from San Diego, California to the Davis Mountains in West Texas. I decided it was a great idea to haul this giant hula hoop of copper wire with me to try to record electromagnetic sounds. It was a neat experiment, but it didn't sound that great and I regretted bringing this heavy spool of wire with me on the bike when climbing over the rocky mountains.

I remember vividly the first experience recording in this way. I had both the VLF mics and my acoustic mic set up, and there was a thunderstorm in the distance. I was listening through both of them. You could see the lightning and instantly hear the pop in the VLF mic, and then a few seconds later the acoustic mics would pick up the sound of the rippling thunder. Because the VLF wave is traveling at the speed of light. And then the speed of sound is much slower, so it takes a few seconds for the thunder to arrive.
Listening to this live was really fascinating, but I was never that impressed with the sound of the recordings. Because one of these big hula hoop receivers is mono, and I generally can't stand the sound of mono recordings in any context.

The next iteration of this process was finding a guy on eBay in 2017 that built these DIY VLF radio antennas. This was a different type of pickup where it was just a tiny little box with a long telescoping antenna that's about six feet long. That was much more portable to deal with, picked up the sounds pretty well, but also had the issue of being mono.

I was able to record some interesting atmospheric sounds with these early experiments between 2015 and 2025, but I was never that impressed with the actual sound of the recording. Mostly because it was conceptually super interesting, but it didn't actually sound that good as a standalone field recording.

The final adaptation of this decades-long hunt to record space sounds in a way that genuinely captivates me was to modify the LOM Priezor design. I started with that open source design and then worked with Tom Benedict to create a 3D printed version that interlocks two of the Priezors together. Doing that gets a quasi stereo recording.
These small hoop antennas are much more portable than the hula hoop size one I was hauling on my bicycle through the desert. Over the years, I learned that the hoop antennas function like a figure eight mic, so they're directional. So if you take two of the hoops and align them perpendicular to each other, you actually get a quasi stereo recording.

I tested that out in Hawaii with a massive storm system coming through, and it worked amazingly well (more on those sounds later).

While two of the Priezors are a solid system, I thought I could take it to another level by creating a tetrahedron of four of the Priezors. Then you have a 3D pickup of the whole sphere, because the hoop antennas are arranged like the tetrahedron of a first order ambisonics mic. This is not a true ambisonic setup by any means, but it does give you 360 coverage. 

You have lots of different options of how to listen to these four channels of audio. You can condense all four channels down into stereo. You can take the four channels and route them into a quad setup. You can experiment with putting the four channels through an ambisonics decoder. There's lots of interesting options with this setup.

I then took this VLF tetrahedron to far northern Finland and spent two weeks trying to record the electromagnetic sounds of the Northern Lights. On three of the nights, we got stunningly strong Aurora Borealis, and I was able to capture this unheard sound of the natural world.

I finally capture space sounds with captivating spatialization. Hallelujah.

I hope you enjoy the clicks, pops, static, whistlers, and resonant noise created by one of the most visually stunning phenomena in the natural world. That's a wrap on my 147th sound library from the natural world, and I hope you enjoy listening to the soundscapes of aurora borealis. I'll talk to you again soon.

BEHIND THE SCENES:

• Stories and sounds from my recording adventures. 
• Coming soon

KEY FEATURES:

• Clicks
• Pops
• Sferics
• Whistlers
• Resonant noise

SPECTROGRAM DEMO:

• A compilation of my favorite sounds from this collection.
• Coming soon

FILE LIST:

• View spectrograms for each track, search, and filter in the Airtable spreadsheet.
• Click "View larger version" in the bottom right corner of the File List below to open in a new tab. 
• Mobile File List viewing is limited. Use a desktop computer for the best experience. 
  

FILE TYPES:

• VLF tetarahedron - 4 channel setup with a variety of decoding options
• 65 northern lights soundscapes
• 50 clips also include stereo wind recordings. So you can switch between the audible world of weather and the unheard world of VLF radio. 
• Read this document for a detailed description of how to use these VLF recordings. 

LIBRARY INFO:

GEAR USED:

• VLF Tetrahedron
• This radio mic was based on the open source design of the LOM Priezor. Source files on GitHub – here. 
• Tom Benedict build this VLF mic for me with some 3D printer wizardry.
  
• Lewitt LCT 540 S
• Cinela LEO-Lewitt (custom wind protection)