8D MUSIC - HYPE OR FIRST STEP INTO IMMERSIVE AUDIO?
The 8D music trend has taken off on YouTube and Spotify. Newspapers are now publishing articles about this new listening experience. Rumors about the technology are being discussed on social media and within the audio production communities (SPOILER: It’s good old binaural rendering). Aside from all the enthusiasm and concerns, there’s one remaining fact to keep in mind, and that is that 8D music has now somehow reached the audience’s attention with hundreds of millions of views on YouTube and Spotify like no other technological audio innovation in the last years. We want to show you how music is produced in 8D and highlight the technique behind this trend. Additionally, we want to give you an outlook into advanced creative possibilities working in immersive audio formats.
These type of productions share several characteristics:
360° sound field: The music seems to originate from varying positions located in a 360° sound field around the listener (left, right, front and back, above and below).
Movement: The sound seems to move in full circles around the listener continually or reacts to the music's dramaturgy.
Localization: The sound appears to be unlocked from the headphones as if the listener were in a realistic room, the so-called out-of-head-localization. PRODUCE 8D (BINAURAL) WITH DEARVR MUSIC
To enable you to jump right into mixing immersive audio productions easily, we’ve created a short tutorial video. This video will show you how to bring your regular stereo mix into the immersive world using the 3D audio spatializer dearVR MUSIC. By inserting the AAX/VST/AU plugin in the last slot of the FX chain in the DAW, we can easily rotate and automate the mix. You can achieve the same externalization and spatialization, as shown in the introductory examples using dearVR MUSIC together with any regular headphones.
THE TECHNIQUE BEHIND 8D
The term 8D doesn't mean anything concrete. In the field of audio production, there is nothing like eight dimensions. All 8D creations are additionally edited stereo mixdowns using a 3D audio spatializer plugin like dearVR MUSIC. The technique behind 8D is binaural audio rendering. This technology aims to reproduce the same sound in the listener’s ears as in a real acoustic environment. The music can be listened to with any headphones.
In theory, the listener shouldn’t be able to tell the difference between the virtual environment and a real sound field. However, there are significant differences between the spatializer plugins when it comes to the reproduction of the feeling of externalization and the localization of sound. The dearVR CORE engine is tested to have the best sound and the best externalization, offering positional 3D audio and true-to-life acoustic room virtualization. It is integrated into all dearVR products (dearVR PRO, dearVR MUSIC, dearVR UNITY).
THE DIFFERENCES BETWEEN 8D, 9D, AND 16D
As mentioned before, the terms 8D, 9D, or 16D don’t express anything concrete for audio professionals. In the 8D video scene, a few definitions seem to have been established.
While 8D tracks are produced using only one instance of a 3D audio spatializer like dearVR MUSIC on the audio track, 9D or 16D productions enhance the process by splitting up the original mix into several components. The audio mixdown is first divided into an M (Mid) and an S (Side) signal. Then, dearVR MUSIC is inserted in each channel to individually rotate and automate both components in the 360° sound field.
FROM 8D/16D TO FULLY IMMERSIVE AUDIO MIXDOWNS
All previously described 8D, 9D, and 16D productions are generated using final stereo mixdowns as the input source of the spatialization process. This workflow is limiting the creative possibilities a lot!
By inserting the 3D audio spatializer dearVR MUSIC in each audio channel/track/bus during the mixing process, we can bring the whole production to a new level of listening experience. Now, individual channels can be positioned and automated, creating a fully immersive audio mix. The following video is showing this innovative mixing process, which demonstrates a creative approach to mixing binaural jazz music using dearVR MUSIC.
HOW DO WE LOCALIZE SOUND? BINAURAL!
In reality, we perceive the localization of sound based on subtle time and level-differences between our ears, as well as spectral information, correlation, and pattern matching. The resulting localization can be described by its three-dimensional position using the horizontal angle (Azimuth), the vertical angle (Elevation), and the distance.
The perception from left to right results from the different arrival times between the ears (Interaural Time Difference), as well as from the relative amplitude of frequencies (Interaural Intensity Difference) through the obstruction of the head and from the spectral reflections from our body.
The directions front, above, behind, and below result from different resonances originating in the outer ears. Each direction has its resonance pattern, which is evaluated by the brain. Also, every human being has individual patterns for different frequencies as the shape and size of each person’s ears are unique.
Every individuum perceives the distance through the distance attenuation, the damping of higher frequencies, and the ratio between the direct signal and the reflections. Additionally, the time difference between the arrival of the direct signal and the first reflections express the so-called Initial Time Delay Gap (ITDG). Close positioned audio creates a large ITDG. The early reflections have a longer path to take in relation to the reflections. Conversely, when the audio source is placed far away, both direct and reflections have nearly similar path lengths.
HRTF – THE LINK BETWEEN THE THEORY AND THE BINAURAL PLAYBACK
By making audio measurements on dummy heads like the Neumann KU100, alterations of the sound field by the listener’s torso, the head, and the outer ears are captured in the so-called Head-Related Transfer Functions (HRTFs).
We can say that HRTFs characterize how our ears receive sound from one point in space. In conclusion, they can be used to simulate the perception of that direction by convolving the input signal with the HRTF.
To sum up, we showed you in this article how you can produce 8D music using the 3D audio spatializer dearVR MUSIC. We discovered the process of binaural rendering as the technique behind the current trend. We gave you an outlook into advanced and creative mixing techniques to achieve a fully immersive mix.If you want to know more about how to use dearVR plugins on individual instrument tracks during your mixing process, please have a look at this article.