Binaural Audio

Sound is extremely interesting when you sit down and think about it. From the volatility of its nature to the seemingly endless uses and applications for it, sound is all around us on a day to day basis. However, very little thought goes into how that sound is received in various situations. Since the inception of speakers and headphones, sound has been received more or less as it was given, head on. That was until the inception of Binaural Audio; audio recorded on microphones designed to mimic human ears. I could attempt to explain this more in detail, but I figured the guys who are pioneering this technology, 3Dio, could do a better job...

Binaural recording is the process of capturing audio using two microphones that are shaped like human ears. When audio is recorded using a conventional microphone, sound is typically captured without any physical obstructions blocking incoming audio waves, other than the body of the microphone itself. Binaural microphones capture audio the same way your real ears hear sounds.  The ears (pinnae) dramatically alter the incoming sound waves, but our brains understand these alterations as directional cues.  In addition, the time delay between the ears gives us proper left/right directional cues.  When you listen to binaural recordings using headphones, the result is natural "human" three-dimensional sound that gives the listener the sensation of being in the space where the audio was recorded.

ASMR: An Underground Community

Recently, a subculture has emerged from the depths of Reddit and Youtube. Known as ASMR, (Autonomous Sensory Meridian Response) it is a widely unknown phenomenon where a person feels a "tingling" sensation in their head, spine, back or other parts of the body in response to certain auditory or visual triggers. ASMR videos are meant to trigger this euphoric sensation in their viewers. This is done by a person whispering (usually a female) or making sounds with objects into a 3D microphone, which creates a realistic atmosphere. Although the word "meridian" is basically a more polite word for orgasm, ASMRers swear that the sensation is not meant to be sexual, but caring or loving. The videos may seem extremely strange or boring to the average viewer, but to thousands of people these videos are a source of relaxation and pleasure. Many people even use it to calm anxiety or battle insomnia.

Here is one of the most popular ASMR videos by youtuber GentleWhispering, with over four million views. To get the full effect, you must wear headphones.

Yes, this is probably one of the strangest things you've ever seen in your life. But for a second, just put aside the fact that you watched either all or part of a video of a woman whispering nonsense into your ears and playing with hairbrushes. What I find interesting about these videos is their use of binaural recording. People who produce these videos use 3D microphones, which are basically two omnidirectional microphones, to make it feel like the listener is actually in whatever situation the actor is portraying. When you put the headphones on and listen to some of these videos, the effect is jarring, because it sounds like someone is actually speaking into your ear. Whether you feel a sensation or not, it is an interesting use of audio that I have never experienced before being used in this way.

There has been no scientific research as to why people feel these sensations or what the sensation actually is, but with such a large following, it's hard to ignore this abnormal phenomenon. The community of ASMR is growing exponentially, and if it proves to be medically beneficial, it may be a better alternative to drugs for those who suffer from anxiety, insomnia or other issues such as these.

Binaural Sound. The New 3d?

Has the buzzword "3D" lost it's buzz yet? It's true, after an explosive renaissance in Hollywood after James Cameron's "Avatar," 3D films just aren't bringing in the incredible margins that they have, even a year ago. As the technology gains more market share, it also loses it's novelty, which is arguably a large part of it's appeal. But three-dimensional visuals aren't the only gimmick in town. Not by a long shot. This is Hollywood afterall.

Before the days of installing new 3D-capable projectors, theaters were in a similar arms race of how many watts their theater's sound system sported. From the beginning of the Talkies, sound technology has steadily been improving from stereo to surround sound. But little known to the general population is another advancement in sound design: binaural sound.

Binaural technology records sound the exact same way we perceive them. Two microphones are placed about 7 inches apart, and a head shaped object is placed between to account for the small alterations our own heads creates. This is different from stereo sound, where the left and right microphones could be placed wherever the sound engineer wants. With Binaural recording, there is a defined perspective. The listener is then placed in the middle of that perspective when they listen through headphones (necessary to avoid "cross talking" between the two sides, or hearing a bit of the left sound in the right ear). This has the unique ability to make sound appear three dimensional. Don't believe me? Try it yourself!

Tip: You must use headphones for this to work

It would be too easy to tell if a sound is coming from the left or right. Somehow, however, you can also hear the sound move frontwards or backwards, and up or down. You can hear the woman whispering behind you, then hear her move to your front. How can only two speakers give so much dimension?

The secret is in the timing of the recordings. The minuscule difference of when sound arrives at your left ear and right ear is not lost on the subconscious mind. Also, the shape of our ears distort and direct sound differently if it is entering the ear from in front or in back. By mimicking the human aural design as faithfully as possible, the effect can become even more effective.

Just like 3D films today, binaural sound recording was developed far before the latest blockbuster films. The first experiments with it actually date back to 1881! Since then, the technology has struggled to find a proper use, despite a fad of musicians recording their albums with it (One example being Pearl Jam's unironically titled "Binaural" album). Despite it's seemingly magical effect, the technology never really "caught on."

This could be due to the fact that the format's practical applications are unfortunately limited. Though some select circumstances in movies could benefit from this total sound immersion, it is a foreign form compared to how we process movies now. It would be akin to showing feature films in 60fps. It may be a more lifelike experience, but it is not part of the audience's internal film expectations. Not to mention, you'd be required to wear headphones on top of those ugly glasses at the movie house. One application that would benefit greatly from this technique, however, is point-of-view video games. Since the audience is already submitting to a point-of-view perspective, it plays right into the audience's coded viewing experience, and add the realism that game developers strive so hard to achieve.

Though it is yet to be seen whether binaural sound will ever find widespread adoption, it still can inspire sound designers to create an ever more immersive soundscape, and make a pretty awesome YouTube video, too.

-Dylan Van Arsdale

Sources

www.filmschoolrejects.com/opinions/why-cant-3d-sound-be-the-future-of-movies.php

http://sciencefictionworld.com/films/science-fiction-films/574-the-death-of-3d.html

http://benbeck.co.uk/firsts/talkies2.htm