What is Binaural Recording?
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If you want to fully immerse a listener, you may want to explore the binaural recording technique, which creates binaural audio recordings that are three-dimensional and will make sound sources and sound waves feel as if they are moving.
Intrigued? We thought so! Allow us to explain further what binaural audio is and how binaural recording works so you may consider using this technique yourself for future projects.
What is the Difference Between Binaural and Stereo Recording?
It’s easy to confuse binaural audio and stereo audio because both recording techniques create an immersive sound for the human ears. However, there are major differences between the two.
Binaural audio produces three-dimensional sound in such a way our human ears will be able to hear the sound source as they would in the real world. Such a phenomenon is achieved with the use of an actual dummy head. This head will have binaural mics embedded in its two ears and be placed in a location to capture sound as accurately and authentically as possible. After which, sound engineers will post-process the recordings made (if applicable) so listeners can get the whole surround sound binaural audio experience.
While a good pair of speakers can enable the human ears to enjoy binaural recordings, binaural audio works best when listening with a pair of headphones. The distance between the left and right headphones will allow for sound waves to highlight their inter-aural time and level differences. In effect, the binaural simulation and sensation can be experienced by our own two ears and the human brain, similar to our head-related transfer function (HRTF).
The Sennheiser Ambeo Smart Headset is hailed as one of the best recording and listening devices that will give your ear canals a pleasant sound trip. It’s designed like hearing aids and an omnidirectional microphone for a comfortable but optimal listening position.
On the other hand, stereo recordings use two microphones to capture audio with mono signals. While there is an illusion of immersion when listening to the sound recording, stereo does not create a multidimensional soundscape, unlike binaural audio. Instead, the immersive illusion is achieved by assigning the two audio channels (left and right) its mono signal with slight variations.
What Are Binaural Recordings Used For?
The goal of binaural recordings is to create three-dimensional sound effects that will somehow stimulate our autonomous sensory meridian response (ASMR) while listening. With that, the recording industry, sound designers, and engineers decide to record binaural audio for many reasons and uses.
Since a binaural recording can trigger the human hearing and human auditory system differently from other types of recordings, binaural beats are being used in healthcare. A binaural beat can be used for self-hypnosis, biofeedback activities, and tests that will tell specialists about the state of one’s brainwaves in response to the sound waves being heard.
Research and studies also show how listening to a binaural recording can be used as a tool to alleviate feelings of anxiety, stress, and negative mental states. At the same time, binaural audio can improve one’s mood, creativity, and attention. With that, sound recordings that make use of binaural techniques make for great meditative and relaxing music.
Filmmakers use binaural audio technology to create an immersive surround sound experience for viewers. Binaural audio places film viewers within the actual environment of a scene because of how well it can capture audio and replicate a sound source in the most realistic and layered way possible. Alternatively, filmmakers also use spatial audio but it is less immersive compared to binaural.
As binaural audio is immersive, game developers have also been using this recording technique and technology to pull gamers into virtual reality. Augmented reality games also make use of binaural recordings to help create interactive and immersive gameplay.
Binaural Audio Recording Methods
There are three recording methods to choose from and these will vary depending on one’s recording style and budget. Nevertheless, all methods will require a pair of binaural microphones and a dummy head. Each binaural microphone will be placed on the left ear and right ear of the head at least a width apart.
Now let’s take a closer look at the three methods.
True Binaural Audio
This method is preferred by individuals who would want to achieve a pure binaural sound recording. It makes use of a dummy head that is anatomically correct — from the shape of a human head, the size of the outer ears, and parts of an ear canal. With such attention to detail, this method can replicate a sound source to a tee that when humans hear it, it remains close to the “true” sound and experience.
In-Ear Binaural Microphones
There’s also a method that will allow you to use your head instead of a dummy’s. After all, a dummy head is made to replicate a human’s so one can alternatively also use their own to record audio. These small microphones will be placed in one’s ear canal similar to stereo headphones and can capture audio the same way as the previous method.
Pseudo Binaural Audio
Although the word ‘pseudo’ is in its name, this method is still able to capture three-dimensional soundscapes. However, it may not be able to completely replicate the actual sound as heard by humans and the sound waves may not have the same ASMR effect that can be achieved by other methods.
Such is the case with this method because it only makes use of a Stereo Ambient Sampling System (SASS), which is a foam baffle between angled microphones. While it can still create levels and differences, the result is not as pure and accurate.
How Do Binaural Microphones Work?
With the need to mimic one’s head-related transfer function in real life, binaural recordings need to make use of specialized microphones. A binaural microphone is small enough to fit inside a human or dummy’s ears so it can be snug and secure in the canal. This design helps the microphone replicate sounds and the environment similar to a human’s hearing.
These microphones also come in pairs as there must be at least a 7” or 18cm distance between the two to create subtle differences in arrival time and volume. This also helps create an immersive three-dimensional sound.
Final Note
Binaural recording is a great and perhaps the purest way to reproduce and replicate sounds the way humans would hear it. For an immersive and experiential soundscape, this type of recording is truly your best bet.
Frequently Asked Questions
Is the Neumann KU 100 a good binaural stereo microphone?
The Neumann KU 100 is hailed as one of the best binaural microphones in the industry, especially when it comes to recording pure binaural sounds. It has a balanced low-noise feature, XLR outputs, and a weighted self-noise. This binaural microphone is also meticulously designed to be securely mounted or suspended via ⅝” threaded holes of a dummy head.
How do you isolate the left and right channels in binaural recordings?
Splitting audio channels and tracks can be done through editing software such as Audacity and GarageBand. These editing applications can allow you to isolate, mute, and delay audio tracks to your preference in case you would like to further highlight the sound and time differences captured by the binaural techniques listed above.
