You Have All Of Two Ears (A Primer on Dolby Atmos, Immersive Audio and Binaural)
"The ear can't hear as high as that! Still I ought to please any passing bat! With my high fidelity. Who made this circuit up for you anyway?" - Flanders and Swann
Up next in my history of rock series is Psychedelic Rock, but how can I talk about psych without talking about panning and audio effects? So, here are some thoughts, musings, findings, and bruisings about stereo, binaural, and the recent craze of Dolby Atmos.
Stereophonic Sound
Into the 1960s, recorded music was mostly made for one speaker. This single-channel “mono” audio has always been strange to me. We have two ears.
Of course, two is twice as much as one, so storage and technology were big drivers here. As tech evolved with advancements in magnetic tape (the stuff the artists recorded on) and the vinyl record (the stuff the labels sold), the recording engineers finally got a second channel to play with.
Incidentally, the earliest surviving recording in stereo happens to be a recording of a piece by one of my favorite composers, Scriabin:
(If you liked that, Scriabin gets so weird in his late works. I love it.)
This Is a Journey into Sound
The newfound fidelity opened up experimentation. Simply by having a channel for each ear, stereo (and headphone) listening became immersive, illusory, and deep.
When you can, check out the first 30 seconds of this gem showcasing the new technology back in 1958:
A Revolution in Audio Effects
With these two channels, we can disperse some audio between each, creating an artificial sense of space. Effects like stereo chorus, delay, reverbs, and phasers came out (or were they discovered?) around this time.
It’s easy to overlook just how big of a deal that was. These were sounds impossible before. Audio that may have never been heard in the history of the universe.
And now they’re used in almost every recording. This is audio developing its own language, distinct from the natural world of discrete instruments. It’s making the song an organism bigger than its constituent parts.
The Tone Poem
A century earlier, composer Franz Liszt invented the tone poem — a musical statement more about frequency and vibe than a form-focused song. The innovations of stereo audio recording, audio effects, and soon the synthesizer spawned genres like ambient, elevating the acoustic Liszt to an unnatural (and wonderful) place.
Isn’t it funny how the simple innovation of having as many speakers as ears can lead to entire genres forming?
Put technology in the hands of creatives and watch the world change…
What’s Next?
Microphone techniques and technology evolved to meet the moment, and binaural recording flourished. Binaural is a technique to try and replicate the natural world. It’s like teleporting your head to a space.
If you have headphones, take a trip to the barber:
Binaural has been used in a ton of music (including my own) but unlike stereo, it can be harder to discern this difference in a mix of music. In other words, going from mono to stereo is like going from black-and-white to color. Binaural is a bit more like going from 720p HD to 1080p. It’s cool, but it’s more in the realm of “oh neat” rather than “you changed the game.” And it’s more noticeable in the right conditions, like the sparsely populated barber shop video.
MOAR SPEAKERS
What if we put speakers all over instead of in just two places? Surround sound (aka 5.1) made movies more immersive. It put the audience on the battlefield. Helicopters flew overhead. Mortar fire flew to our left and right.
But like binaural, that surround-sound effect hit harder for individual elements like explosions and helicopters and a little bit less for a guitar or a synth. Surround mixes are neat. I enjoy them. But there’s a reason why it didn’t catch on. It’s expensive and…
We have all of two ears.
Dolby Atmos / Immersive Audio
So what is Atmos? Atmos (and other immersive audio protocols) improved on the 5.1 surround system through something called object-based audio.
Basically, instead of panning (aka placing) a sound into a specific speaker, you create an object and then move it around in a virtual 3D space. The system then reads these objects in real time and assigns them to the closest speaker. That allows you to listen to Atmos on a soundbar or on a perfect nine-speaker system without changing the file type. Neat!
One cool part of Atmos is using vertical space. You can have the guitars get higher. It’s like the elevator in the Haunted Mansion. Neat!
But the fact remains. We have two ears and limited perception.
Speaking of Human Perception
Even trained musicians have a hard time discerning differences in sounds when there are too many of them. Some pop mixes have hundreds of elements playing at a time. It’s hard to tell if one is above you or in front of you. Information overload!
Have you ever done a blind spot test? Everyone has blind spots! Your brain fills in the gaps in the areas of the eye without light-sensitive cells.
Audio is similar. We’re simply not as good at telling how high things are. Things behind us sound quieter than things in front. These “psychoacoustic” effects make implementations of Atmos harder. Not impossible, just a bit more muted.
But Still, Try Atmos!
That’s not to say it’s not cool! I got my Atmos certification, so I’m no hater. But I am a realist about it. Like binaural vs. stereo, Atmos feels a bit more like a technology in search of a creative answer, rather than the answer itself. It might just be early, but the fact still remains:
We have all of two ears.
It’s still neat tho. Try it out here.
(But notice how the visuals on the site are designed specifically to bias you? Of course, Atmos is trying to sell its product, but I’ve seen it lose in blind comparisons.)
Listen/watch this week’s podcast to pass the pan with Mike Post who runs MooseCat Recording in LA and recently built a dedicated Dolby Atmos Room 📦
My Take
I think movies and video games have a better case for immersive audio than music because they are more sparse. It’s easier to isolate and visualize each audio object in space. Maybe entire genres will pop up around Atmos though — like how ambient was spawned from stereo!
The magic of this new medium is in the interaction and the perception of the elements. So video games that use music heavily could be really cool using this technology! Or what about art exhibits!?
But for everyday listening, there’s a reason why stereo is king.
One last (nerdy) thing. Part of the magic of stereo is called crosstalk — the amount of bleed between the two channels. That can be controlled in sections to create very different impressions of space. That leads to the ability to blur audio between your ears.
Consider how fundamentally different that is from object audio… in Atmos’ object audio, a guitar is an individual unit, moved around in space as you would a performer. In stereo mixing, a guitar is a frequency, made to be blended, blurred, mashed, and transformed beyond a guitar — beyond the object — and blended into the greater mix instead of distinct from it. Sometimes you want to hear the individual performers (such as a mix of a live concert!) but sometimes you want to go beyond.
Into a future of the previously unheard.
I’m sure Atmos (or something like it) can play a major role in that future, but it’s another tool in the artist’s bag.
But it is pretty neat.
Thanks for reading, internet friend,
Scoob