Seeing Sound

Our senses seem like they’re cordoned off from one another. Hearing and touch don’t seem to have much in common, but then when you consider that you can both feel and hear vibrations, and how your eardrum vibrating is how you hear, things start to get blurry.

Similarly, if you look up at the Sun, you might sneeze (but probably only some of you), as I wrote about yesterday. You can feel those rays hitting your skin and you can see them, even though they’ve traveled a long way to get here.

Taste and smell, too, are very closely related. A flavor is made up of some combination of these two senses, and the line gets really blurry while you’re eating and drinking.

The more you get into it, the more you can see that our senses are actually very closely related. They’re just ways of taking all the data coming in from the outside world, encoding it in some useful manner, and then sending that useful signal to the brain. In a manner of speaking, we all see, hear, smell, touch, and taste in the binary, for the signal has to reach our brain at some point, and the only way any signal reaches our brain is by way of electrical pulses.

We’ve even figured out how to encode sounds from the air into sounds we can feel… or even see. If you turn that Def Leppard record (it’s okay to admit that it was Hysteria and not one of their earlier ones) at an angle, you can see the little grooves where the needle can follow the same waves the sound made when it was initially made.

Recorded sound is impressive, but there’s also a way to experience a sound right as it’s happening. I was a huge fan of one of these ways of hearing sound when I was 17 years old and saw punk bands play behind walls of speakers. The speakers would pulse with the sound the band played, encoded into electrical ones and zeros, then blasted back out.

You could feel the sound anywhere in the club, but I really enjoyed the feeling of being closer to those speakers. Side note: it’s kind of impressive that I can still hear well today. You could also see the speakers pulsing, so you got a good sensual bombardment from just the speakers.

Let’s zoom in on that speaker for a moment. When it vibrates, you have both a visual and audial wave passing through the apparatus.

Someone had the idea to set up a speaker that was pointed toward the ceiling, and then putting sand on top. When the speaker comes on, the sand starts to dance into specific geometric designs, like this:

This effect has launched a field of study called cymatics, and it focuses on different ways to see sound. If you use a different frequency of sound, you end up with a different geometric pattern.

Sound waves—the same phenomenon that gets reflected in the actual physical shape of the Def Leppard record we were talking about earlier—have their ups and downs. These peaks and troughs are far from uniform in a sound wave, and this is reflected in the design the sand on the speaker (or on top of the plate that’s on top of the speaker).

There are some areas of much higher vibration, and you can see the little grains of sand steadily vibrating away from these intense zones. These are called antinodes, places where things don’t like to gather together. Nodes, by contrast, are the quiet, still zones where everyone wants to just hang out and chill.

Feeling music all those years ago gave my mind the spark that started this thought process. For some reason, I was reminded of my visit to the eye doc last week.

They do this thing where they sort of punch your eye with the air, colloquially called an air puff test. The idea is to measure your eyeball’s internal pressure, something important for preserving good vision.

That little punch of air is a lot like these little punches of sound: you can feel them, but just barely. Your eye, evolved for sight, can also feel. Your ears, evolved for the purpose of hearing, can feel, too. Our senses are much, much more similar than we might at first believe.