As Apple announced in a press release on May 17, the entire lossless Apple Music catalog is now available in to all subscribers of the streaming service – without further charge! This very pleasant news for audiophiles apparently not being enough for the Californian tech giant, support for the 3D audio format Dolby Atmos was also launched at the same time! What is this all about?
“Spatial Audio” promises a new dimension of music enjoyment. While Apple Music isn’t the first to enable 3D music streaming, this bold move means that 3D music is expected to become more prevalent in the coming years. The announcement has caused quite a stir among music fans and creators alike. Is 3D audio really here to stay? Is the third sound dimension a revolutionary leap or just another short-term hype?
As things stand, multiple music streaming services including Amazon, Deezer, Tidal, and more obscure representatives like Hungama offer 3D streaming besides Apple Music. However, the scope of the 3D catalogues offered is still very different, and an upgrade to the HD or Hi-Res subscription is still necessary in most cases. Market giants Spotify and YouTube have not yet followed suit, but are being put under pressure by these developments. We will see how they will position themselves in the 3D audio context.
Provided an up-to-date iOS, all current iPhones, iPads and Apple TV 4K as well as AirPods enable music consumption via the Dolby Atmos format. Owners of Beats headphones or soundbars can also enjoy the three-dimensional music experience in many cases. Dolby Atmos is therefore already possible in many households without the need to purchase additional hardware. Mobile devices from Samsung, Lenovo, Huawei, Nokia and Razer are also among the devices on which Atmos can be consumed, 3D support from Apple Music is still pending, though.
Object-based audio has been common in the film and gaming sector for quite some time, but the music sector has kept a low profile so far. Some of the largest topics of the majors have been producing for Atmos more and more frequently for several years, so that many more recent releases are already available in Atmos format. In addition, numerous original recordings of timeless classics (e.g. Beatles, Herbie Hancock, etc.) have been released as Atmos versions in recent years. So there is no lack of content, and we can expect further growth in the 3D catalogues in the near future.
But what’s actually different about “Spatial Audio?” Well, it’s three-dimensional, meaning signals can be placed not only on the stereo stage between right and left, but also on the side, back, top or bottom. Often the difference is rather subtle for the average person and only become obvious in direct comparison, as long as these possibilities are not overstimulated for effect purposes. However, a good Atmos mix is accompanied by an increased degree of so-called “immersivity”, i.e. the listener feels more “in the music” than when consuming a conventional stereo mix.
How does it work?
Conventional audio formats are channel-based, which means that each speaker is assigned by its own audio track. There’s one channel for mono, two for stereo, 4 for 4.0, 6 for 5.1, 8 for 7.1 etc. This works great, but requires that consumers use the same speaker setup. With mono, this was unproblematic, because it doesn’t really matter where the speaker is located. With stereo, this is still feasible, because a more or less equilateral triangle can be integrated well in almost any living room. But if surround formats come into play, it gets more difficult, because the surround speakers are often placed sideways or even in the wrong order due to lack of space – that’s it for the 3D experience … And when it comes to ceiling-mounted speakers, it gets even more expensive and complicated. And of course, multi-speaker setups are anything but mobile. In short: surround is great, but only partly suitable for everyday use.
Dolby Atmos, on the other hand, is an object-based sound format. This format also works with audio tracks; however, the tracks are not assigned to a fixed loudspeaker but are placed in a virtual room by means of three-dimensional coordinates. Each object is accompanied by metadata that is transmitted together with the audio signal and decoded by the playback device for the respective listening situation. Up to 118 such objects can be placed independently in an Atmos mix. The separation of signal and loudspeaker enables a three-dimensional sound experience that works more or less independently of the number and placement of loudspeakers. An Atmos mix can therefore be played back on pretty much any speaker combination, from a home hi-fi system to a cinema, and the sound sources are distributed as good as possible to the available speakers based on the metadata during playback.
The playback also works on headphones, in this case it is called “binauralizing.” The result is that only two channels reach the two ears separately. This sounds great, but it also means, you can safely avoid the detour via an object-based streaming format and directly provide a binaural mix to get the same listening experience. However, a fully binaural mix is only conditionally compatible with speakers, which is of course a limitation.
Besides Dolby Atmos, there are other sound formats that work object-based: Sony 360 Reality Audio, DTS:X or Ambisonics are among the more widespread ones. However, Atmos is currently clearly ahead in this race in consumer circles.
Is the future 3D?
Let’s not kid ourselves: Again and again in the past decades, new formats came onto the market that, after a short-term hype, failed to establish themselves in the long term. So, doubts are not unfounded. What’s different this time?
Well, historically, most formats failed primarily because of a relatively high level of complexity, high acquisition costs or a lack of distribution structures. No matter how impressive a new media technology may be, if it is not practical, convenient and, above all, affordable for consumers, it will hardly be able to gain a long-term foothold. Now, however, the critical points seem to have been solved in the case of Atmos: In most cases, no additional purchase is necessary, the learning curve required for consumption is zero, there is no shortage of content and, most recently, some of the largest streaming providers have started offering the whole thing at no extra charge. For many listeners, the 3D experience requires just a single click. So the question is basically: will people click? This will ultimately determine whether the additional investment in 3D content pays off for labels, studios, producers and artists – it’s business after all! But that also means: It’s in our hands. Both Apple and the major labels seem to believe in it.