Diving into new sound dimensions with binaural recording

Have you ever listened to a song and felt as if you were standing in the middle of the room and the band was playing around you? You were probably listening to a binaural recording.

What does binaural recording do?

A binaural recording relies on two microphones, instead of one, in order to create a 3D “soundscape” for the listener. Essentially, this style of recording immerses the listener in the song. While complex in sound, the procedure for recording binaural sound is relatively elementary. The microphones are simply placed in the ears of the dummy. When a song is recorded, the sound waves reach the microphones at different times as when one of the microphones is closer to an instrument, the sound waves captured are stronger (science).

The dummy head plays a significant role in creating the soundscape. Because microphones are placed inside the dummy’s ear which are constructed to replicate a real ear, the sound waves are altered during the recording process. These alterations match how the sound waves would alter in real life. These alterations are called interarual cues, and they stitch together the 3D soundscape. Because recording has two isolated inputs – two microphones, one per ear – listening must be done on a device that allows two isolated outputs, such as headphones, as opposed to a speaker system.

This can be heard when listening to “Snakecharmer” with headphones: soft tickles from a nylon guitar can be heard toward to the  right, with a mellow, clapping percussion sounding even further to the right. At one point, the guitarist circles the dummy head, and the interesting melody is heard in orbit.

The history of binaural recording

The first binaural recording occurred in 1933, when AT&T Bell Laboratories brought a binaural prototype to the Chicago World’s Fair. This device attached the two microphones on the cheeks of a dummy. The dummy was enclosed in a glass room, with various sounds surrounding it. Spectators could listen in via headphones from outside. It wasn’t until about 50 years later when it was realized the key to higher sound quality was putting the microphones in the dummy’s ears.

Binaural vs. Mono recording

Binaural recording sounds ridiculously better, so why do so many albums feature only mono recording? It’s pretty simple: with how intricate binaural soundscapes are, it is very difficult to alter the sound. With two isolated inputs, each alteration process would have to be exact enough to preserve the sound scape. If one of the inputs were altered too much, the illusion of 3D sound would be ruined.  

When is binaural recording used?

Because of the difficulty of altering binaural recordings, little binaural recording is done in music. Most of the binaural recordings that exist today are for meditation, sound stories, or ambient experimental music. There are a few musicians, however, who have experimented with binaural recording.  Best Coast released a live binaural recording of their song “Baby I’m Crying” off their album Fade Away (2013). Julian Casablancas of the Strokes and Jason Schwartzman of Coconut Records have also experimented with binaural recordings.

The future of binaural recording

Several different audio companies, including Choueiri and Jawbone have explored a filter (in the form of an app) that creates the illusion of 3D audio, without using the dummy head recording method.  As virtual reality becomes more prominent, 3D audio is rising at equal speeds. Oculus and Sony both have VR prototypes, and both include elements of 3D sound. Adam Somers of Jaunt said: “Binaural audio is critical to an immersive experience within the context of VR. We consider audio to be 50 percent of the immersive experience.”

Binaural recording truly is the sound of the future. As technology advances, binaural recording will allow our easy listening to transform into an immersive soundscape. Next time you hear a song that sounds 3D, just remember: musicians recording that song while being positioned around a bodiless, rubber head.

Written by Brendan Redmond

Photo by Kall Binaural Audio