spatial audio

How a MS product in Unity may save your 3D audio

In 1931 while working at EMI, Alan Blumlein invented Binaural sound showcasing the possibilities of stereo sound (using a "Blumlein pair" mic setup) in entertainment. Among his 128 patents centered around audio and television technology we can thank Alan for stereo records, stereo films, surround sound and even Earth's first high-definition television broadcast; at a breathtaking 240-lines or better. Alan understood waveform structures with how they populated and translated to a signal we can capture, save and playback. With modern technology we can often find ourselves still referencing the very beginnings of audio recording arts and sciences from humans like Alan Blumlein.

One the biggest topics amongst audio folks in 2016 was all of the variants of immersive audio ie: VR audio, AR audio, HRTF, Spatial Sound and 3D sound. Also, remember how we're all up in arms on "what will the 3D audio standard be?"  Don't freak out, they're all actually related and Unity just made it even safer to not freak out. As many audio people will say, a lot of spatial audio-panners have a variety of shortcomings. None seem to do all of the full job; panner "A" may have excellent approach on the object but fail miserably when the object passes overhead beyond the 45 degree mark. Panner "B" may have excellent approach, believable overhead transfer but aggressive side-panning (intervals of 20+ degrees). Then maybe there's that one spatial panner you've found that works for your project-needs but it's too expensive and that's the end of that discussion. Unity 5.5 alleviated this predicament with the introduction of the 'Microsoft Research Head Related Transfer Function' (Spatial Sound). I'm sure many saw it in the notes of the "what's new in Unity 5.5" but you must experiment with this panner before you commit to your teams next decision on spatial audio. 

What you need to know about this panner to trust it. 

-It was developed by some of the pioneers of original digital audio coding based off Alan Blumlein's Binaural principals. 

-It comes FREE with Unity 5.5

-Works just as well with music as it does sound effects and dialogue

-It was designed to work with any headphone (Alan Blumlein principals) 

MS has been studying anthropometrics for a long time and building metrics on it; "the study of the human body and its movement, often involving research into measurements relating to people. It also involves collecting statistics or measurements relevant to the human body".  This study allowed them to program the best parameters to accommodate a general-mean of HRTFs. When developing for a consumer level product you need fast results, that carry reliable features. I love fancy hardware but I am an audio professional, us alike have a near cult-like obsession with audio and it's existence. We can not be the subjects of what hardware non-audio professionals will desire. In the consumer world, data will prove the masses desire accessibility at a low entry fee. An efficient way to achieve this is by using software that works with existing hardware/platforms people are familiar with. Mr. Blumlein looked at a singular speaker as a 360 degree plane, a speaker is a circle. Why couldn't you use each degree point on a speaker as a focal point for sound? You've already heard it in some of your favorite music even. A speaker re-produces sound from thumping out sine waves in a "middle-out" fashion, with each degree of the speaker cone representing a different frequency spectrum for that particular speaker and driver. Stay with me...I'm going to draw a terrible picture to show you: 

If you grew up in a city environment, you might recall seeing sound designers, or "prepared instrumentalists", people like John Cage. These extra cool humans were able to translate moving sound with one singular speaker by understanding the frequency spectrum of the speaker they were using because they knew how to "throw" sound. Why not apply this technique using modern software and proven hardware?  I found the MS Panner to be a solid solution for our next project. It can be used for any Windows 10 application, and with optimal performance using VR/AR and head tracked headphones. If you’re concerned about monetizing on this why not charge a fee for variations of immersive experiences, give people a tiered system based on their budget and needs:


Option A $ -3d'ish

Option B $$ -3D

Option C $$$ -I want the full experience, put me in the Matrix

Consider your game or app at hand, is the audio supposed to move with picture? If so maybe a hardware solution is required. If you're developing for mobile gaming or entertainment for the home then a software based solution using existing consumer hardware may better suit your audience. Involve audio early, a lot of us understand the pitfalls of this technology and proper planning will save you money and development. Don't get bummed MS came up with what could turn into the standard for spatial audio...Remember Phillips came up with the CD "Redbook" standard and Dolby and DTS pioneered all of our modern audio protocols so it's par for the course that a major company would develop the breakthrough in 3D audio. I'm most stoked it comes with Unity and we won't have to allocate additional costs for a panner we want to use.

Happy gaming!

-Josh - @jealousaudio


Noteworthy topics:

'Spatial Sound in Unity' guide

What the devs are saying (a MS dev blog)

What is actually in Unity 5.5


- Tashev, Ivan , Hannes Gamper, and David Johnston. "Spatial Audio." Spatial Audio - Microsoft Research. Microsoft, 1 Dec. 2015. Web. 2 Mar. 2017.

-Thornton, Mike. "Alan Blumlein - Inventor of Stereo Recording." Alan Blumlein - Inventor of Stereo Recording. Pro Tools Expert , 10 Feb. 2017. Web. 2 Mar. 2017.