There’s Absolutely No Downside to Dolby Atmos

In recent years there has been an avalanche of incredible new and varied content to stream. And thanks to improved Wi-Fi and mobile data speeds the “all you can stream buffet” is increasingly consumed on the go. There’s also been an increase in the use of more sophisticated audio formats. Whereas stereo reigned supreme for nearly half a century, 'immersive', '360' or '3D' formats are becoming increasingly common. 

These terms have become interchangeable – a way to describe sound which spreads beyond the constraints of the left - right horizontal sound stage offered by stereo. As a sound designer I think it’s important for you to understand that different situations and scenes can call for different levels of immersive format.

In a physical environment, such as a cinema or your home, multiple speakers can be placed around the listener to create more immersion. And over the years, we have seen many experiments with different speaker layouts to create the best experience. For many years Dolby’s 5.1 system was adopted as the standard (stereo front speakers plus a centre speaker for dialogue, a sub-woofer for low frequency sounds and two rear speakers). 

Dolby has since added more speakers to its system which then allows different elements of the mix to be sent to more places within the room – so more speakers along the sides and rear, and finally overhead. This latest iteration is known as Dolby Atmos. The great thing about Atmos is that by increasing the number of speakers, sounds aren't jumping as far from one speaker to the next, allowing the sound to be more fluid and pin-point accurate in the listening space. For films in movie theatres (which have to be properly built, acoustically tested and then licensed) it works extremely effectively – the Odeon Luxe Cinema in Leicester Square, which boasts a massive 400-speaker Dolby Atmos array is probably one of the best sounding theatres in the world. 

Building on this success, Dolby has made Atmos available in the home. However, it takes money and the willpower to rip your walls and ceilings apart to accommodate the 34 speaker locations available to a domestic Dolby Atmos setup. Faced with this, most people will prefer to have their sound delivered from speakers at the front of the room which fire sounds in different directions to trick your brain into believing it’s coming from multiple speakers around you. But since the average home hasn’t been acoustically designed in the same way as a movie theatre, it’s never going to sound anywhere near as good as even an average commercial cinema.  

Dolby Atmos wraps speakers around you and above you (like a dome), but does not provide any sound source which would naturally come from below shoulder height (roughly). This isn’t a problem in some cases, however, in the real world we hear sounds from every direction – and most of the sound we hear is actually reflected off the biggest surface we are in proximity to.  Which most of the time is… the ground.  

Our brains are very adept at working out where a sound is coming from based on 'localisation' – the minute timing differences and colour of a sound reaching our ears. So while panning sounds around and above in a room is more immersive than just front speakers, it doesn’t quite create the illusion of the real world.  So, whilst Atmos would meet most people's understanding of 'surround sound', in certain cases, you may need another option. 

To retain the full sphere of sound in every possible direction, complete with all the 'below' information needed to fool your brain, you need to record and mix either binaurally or ambisonically. When you playback sounds recorded and mixed this way, we believe we are actually present in the scene, right in the heart of the action. And this is where headphones have come into their own. 

Content, as I said earlier, is now commonly streamed on the go and headphones isolate the listener from acoustic imperfections, and hey, you don’t need all those speakers – you just need left and right. If the content is mixed spatially and encoded as a binaural stereo file it will retain all the immersion that was present in the mix. Spatial audio mixed ambisonically (within a full 360 sphere of speakers either physically or virtually) will give you sounds from all directions which comes in super useful for scenes where this added element is required to create a more realistic effect. 

Take a recent immersive audio drama I was asked to consult on. It had been mixed in Atmos, except there was a scene where a character falls through the ice into deep water. As the character falls, we fall with them - dropping into the freezing water, hearing sounds from the depths of the water below whilst her friend desperately calls out from above. Mixed in Atmos, the fall couldn't quite translate as there was a lack of 'down' or 'under' information – which was crucial to make this particular scene work.  

Everything felt too close in height, all on the horizontal plane and spatially unreal for the scene. So, we remixed it ambisonically and it came to life – the difference is astounding.  

I love the scope that mixing ambisonically gives us as creators to really construct environments that feel real to the listener, and I reckon it's a subject that deserves more understanding by everyone involved to really make the most of what is becoming an increasingly popular format.  

To that end I've put together an immersive audio masterclass at Jungle which is an entertainingly hands-on way of learning more. If this article has piqued your curiosity and you want to discover more about how immersive audio can be applied best to different scenes, please get in touch!