In the world of podcast and audio drama there is an audio format that is gaining strength and becoming increasingly popular among the various options offered on streaming platforms. We are talking about the Binaural audio.
That is why in this week’s article we will address this issue so that creators, producers, engineers and listeners, know their qualities, benefits and cons so that they can decide whether this format is what they are looking for.
Binaural Static Audio
The type of binaural audio used in podcasts and audio dramas is Binaural Static Audio, which aims to generate the most immersive listening experience, giving the possibility of perceiving 3D audio with the peculiarity that it practically does not require additional equipment on both the production and listener side.
Stereo
In stereo podcasts, “panning” is a very common resource that is used to generate a little more immersion, because it adds a bit of directionality to the sound by being able to place it either to the left or to the right.
With Binaural Static Audio, the possibilities are expanded to three dimensions, so that now the listener will be able to perceive sounds from above, below, left, right and any point in between, also adding distance perception from the origin of the sound. But how is this possible?
There are essentially two ways to produce Binaural Static Audio, the first is to record the audio with a special stereo binaural microphone or dummy microphone. The second option is to emulate a binaural microphone recording with any stereo or mono track by applying the Head Related Transfer Functions or HRTF. It is thanks to the information provided by the HRTFs that we can give a 3-dimensional feel to practically any mono or stereo audio.
HRTFs provide us with the necessary information for our brain to interpret the directionality and location of a sound through three perceptual properties that we take for granted, which are: the interaural time difference (helps to define the sound source location), the interaural level difference (helps define the sound source closeness) and the resonances and filters caused by the ear, head and neck (which help give a more realistic feeling due to the tonal change of the sound due to the body and location of the “spectator” with respect to the source of the sound).
There are plugins that help the engineer to be able to apply these properties to sounds in mono and stereo format, which is why it is now much more accessible to produce podcasts, audio dramas and even binaural music. However, this is a resource that we should not abuse, since if we apply it to sounds with which the listener is very familiar, for example, some acoustic instruments or human voices (especially if they are fulfilling a leading role such as a lead singer of a song or a narrator within a story), they will undoubtedly notice something strange and this feeling could function as a kind of distraction.
Our recommendation is to evaluate in what specific moments we can use this resource in an intelligent way so that it can enrich the story telling. For example, applying binaural mixing to voices must be done with care, since to achieve the 3D effect the sound will have changes in its tonality, thus affecting its clarity and intelligibility. However, if binaural mixing is applied in a scene where elements occur around the character’s point of view (explosions, metallic noises, or any element whose location provides important information), it can be a great success to increase the immersion.
BBC UK Sound Supervisor Catherine Robinson makes the following recommendations regarding the use of Binaural audio:
- Always think on your audience point of view. Remember that mixing on stereo is like hearing from the point of view from an audience in theaters. Binaural mix actually takes your listeners to the stage where all the action happens around them.
- Less is more. When you have less things going on at the same time the immersive audio is very clear.
- Always start with quality recordings because immersive audio may reveal some unwanted sounds of each track.
