The first time I saw the term “binaural audio,” a stranger was pretending to brush my hair while whispering nice things into my ears. This was the first in a series of ASMR videos this creator would put out into the world. Some call these kinds of shorts relaxing, some think they’re super creepy, but nevertheless, her words — which were coming, somehow, from the back of my head — elicited goosebumps, as if she were standing centimeters away. That video wouldn’t have been half as effective without a realistic, three-dimensional effect known as binaural audio.
Why is it cool?
The binaural audio setup is meant to reflect the way we receive sound in real life, creating vivid and rich soundscapes you would experience if you were actually there. This creates an immersive experience, like virtual reality for your ears. With the power of binaural, sounds are clearly recognizable from all directions, whether that is above, below, behind, far in front, etc.
How does it work?
In film, sounds are traditionally recorded using one microphone, known as “mono,” or two microphones, known as “stereo.” Binaural (pronounced bin-aural or bi-naural, take your pick) audio is actually an upgrade from stereo, as the microphones are placed on a person’s ears, or inside eerily ear-like imitations on a dummy’s head. The latter contraption (seen in Figure 1 below) is then attached to the top of a camera. Since the head is between the two microphones and each are shaped exactly like a human ear, the sound recorded by that device is as close as you can get to a real audio experience from the perspective of a human.
In-ear binaural microphones (Figure 2) work in the same way, except instead of a fake head, it’s your real noggin.
Headphones vs. speakers
It’s super cool, right? I mean, why doesn’t every artist use binaural audio?
Although binaural audio sounds OK coming from speakers, this type of recording was designed for headphones so that the sound can be focused directly into your hearing wings (as our staff member Andy calls ‘em). Nevertheless, the recording will sound different for each listener, depending on the size, shape, and position of his or her head and ears.
Let’s try it out. Find yourself a pair of snug headphones, and lose yourself in the the enveloping sonic wall demonstrated in the video below.
Feel like your mind’s playing tricks on you? For binaural audio, the orientation of the sound is but a playground. As shown above, filmmaker Matt O’Hare used in-ear microphones to create the powerful, chill-inducing effect of an ancient practice. According to Matt, “The appeal is that they cost relatively little, and produce recordings that are unique to the physiology of whomever is wearing the microphone pair.”
Matt brings up a good point: price-wise, in-ear microphones range between $100 and $150 a pair, while binaural microphones attached to a dummy head can cost between $5,000 and $8,000. However, if you can forgo the features offered, you can improvise by using a styrofoam head or even a hat stand, as was implemented in the video below:
How does it compare to surround sound?
Surround-sound systems use a slew of speakers to create the illusion of a 360-degree bubble around the listener. Binaural audio, on the other hand, documents precisely where each sound is coming from based on the perspective of where the microphone was positioned. Therefore, unlike surround sound, binaural is not fit for a large space such as a movie theatre. For instance, if you’re watching someone being abducted by aliens on the righthand side of a movie screen, surround sound will play the whirring of the UFO through multiple speakers on the left side of the theatre. By contrast, listening to binaural audio via headphones provides the sound of wind rustling the leaves of the surrounding forest trees, the chirping of crickets at your feet, and the laser beam of light carrying out the kidnapping directly above you. All of the little details that send chills up your spine. Too cool, right?
How can you best use it?
Although the origins of this recording method can be traced back to Parisian opera houses of the late 19th century, only now are media makers beginning to realize binaural audio’s greatest potential. With the emergence of VR as a new and exciting frontier in film, there is no alternative to the use of binaural audio for a truly 3D experience.
So how can you use it? With the intimate mobile movie theatre Vimeo provides on a personal device, binaural audio can benefit your film on this very platform. There are all kinds of films in which you can give your audience an all-encompassing sound hug. Take, for example, British filmmaker Chris Forshaw, who used binaural audio for his horror film Awake. As he puts it, “I think binaural audio is particularly advantageous to horror films and suspenseful scenes where every little sound can put you on the edge of your seat. And it can really help to draw a viewer into a scene, as it’s the audio equivalent of 3D.”
The next time you’re thinking of ways to take your film to the next level of reality, consider using this amazing tool. For more tips on how to turn the sound on your film up to 11 (are you guys tired of this reference yet?! Tough noogies.), have a look-see at our lessons for learning the essential audio terms, creating sound-mixing spaces, and recording natural sounds. Now get out there and capture some noises!