LIVE SOUND
Hugo Larin is the director of business development at Fluxx ::, as well as the principal and head of business development at LS Media . He can be reached at hugolarin @ lsmediapro . ca . www . lsmediapro . ca . www . flux . audio .
By Hugo Larin
Spatial Audio for Streaming Live Events
Part One : Adding a Sense of Reality to the Virtual World
If there is one thing that the global
shutdown has proven , it ’ s the need for all of us to be more creative than ever – creative in organizing ourselves , organizing our work , and ( re ) learning how to make a living in these unusual times . It ’ s a tremendous opportunity to redefine how we do things .
Sports and entertainment production professionals have a primary focus these days : how can we host events with acceptable social distancing and safety precautions or , barring that , how can we create realistic virtual experiences without a physical audience ?
Of course , it ’ s impossible to replace the energy and communal feeling of a crowd and the excitement that accompanies being at a live event . Our physical senses are what capture these unique moments ; the visual landscape of the crowd and the physical vibration of a venue filled with fans are aspects that can hardly be replaced . But understanding the science behind how our senses respond can go a long way in helping us to create a better immersive experience .
Stereo vs . Spatial Audio One of the dominant senses that can ’ t be ignored in a live crowd is our auditory system . At a concert or sporting event , of course , you ’ re hearing the sound from the PA system , the crowd cheering , and all the other incidental sounds . But your auditory system is doing much more than just receiving those sounds , and most of it subconsciously . It ’ s processing all the audio reflections coming from every direction and delivering a specific spatial acoustic signature of the place you are in to your brain .
There is research that points to these auditory references as critical to making the connection to the visual . And it makes sense – our auditory and visual systems frequently work together to facilitate the identification and localization of objects and events in the external world .
Now let ’ s look at those virtual events that we all have been part of in recent months . Everyone is isolated in their own online bubble , wearing their favourite Bluetooth earbuds or a pair of wired headphones for better audio quality . In the best-case scenario , they ’ re on the receiving end of a good stereo mix ; in many others , they ’ re hearing a cheap microphone in a room with bad acoustics . Small wonder that the experience is less than compelling .
So where ’ s the problem here ? In short , “ real life ” does not exist in stereo . Putting a speaker ( or earbud ) in each ear enables us to create a reasonable stereo or mono sound field in both ears .
But that ’ s not how we hear . Our auditory system is far more complex . Every single sound , direct or reflected , arrives at both of our ears ( interaural ) at a different time and a different level . ( These are referred to as ITD , interaural time difference , and ILD , interaural level difference .) So it makes perfect sense that while a typical twochannel signal can deliver a nice stereo mix , it simply cannot render the sound sources all around you , and the sense of 360-degree immersion that our brains associate with being there .
Immersive Audio But now , new spatial audio technologies employing binaural synthesis are finding new ways to deliver that immersive sonic experience .
Binaural techniques are far from new ; they are heavily used in gaming , VR , sound installations , and in the streaming of 360 video content on various community platforms . Innovative broadcasters have been using them in production for streaming live events as well . In fact , references to binaural concepts can be found dating back to the late 19 th century .
Needless to say , the subject has gained new popularity in the last few months . Binaural immersive mixing is essentially a method of processing the sound sources intended for the listener ’ s ears on the same two headphone channels normally used for stereo , but containing all the aural cues critical to creating the live immersive experience . When done well , it can deliver a critical sense of reality to these virtual worlds and events .
In part two next issue , we ’ ll talk about object-based mixing and how that creates immersive , realistic audio experiences !
60 CANADIAN MUSICIAN