Spotify will introduce CD-quality lossless audio streaming, in a new service for premium subscribers to be rolled out in selected markets later this year.
The streaming biz was early to market with its service, launching in 2008 when music downloads were more of a thing, but is facing competition from Apple Music and Amazon Music, both companies able to integrate the music service into other products such as iPhones or Echo and Alexa devices.
Differentiation is difficult, but lossless audio addresses the most fundamental part of an audio service – sound quality. At Spotify's Stream On virtual event yesterday, Billie Eilish and her brother and musical partner, Finneas O'Connell, attempted to articulate the benefits of lossless audio.
"There are things you will not hear if you don't have a good sound system... there's so much detail," said Eilish, while Finneas offered: "It's an expansion of actual frequencies that you're able to hear through headphones or through speakers, it's in the details, there's so many little weird things that we've buried in our stuff."
Spotify HiFi will link to Spotify Connect-enabled speakers and the company said it is working with speaker manufacturers to enable this.
Late in 2019, Amazon introduced Music HD, with lossless audio in both CD quality (16-bit, 44.1 kHz) and a few tracks in "Ultra HD", 24-bit and up to 192kHz. Now Spotify is catching up, at least with respect to CD quality, and both will be hoping for some advantage over Apple Music, which has lossy 256kbps AAC streaming. Majors getting into the game may also make it harder for specialists like TIDAL and Qobuz, both companies that appeal to audiophiles by offering lossless high-resolution streaming.
Media and technology analyst Mark Mulligan told us that lossless audio from Spotify is "part of a broader market shift not unlike HD in TV... Consumers wanted HD TV because it was what they were being marketed. Though the market dialogue is skewed by being dominated by musos who think hi-res quality audio is more important than it is."
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A dig at Eilish and O'Connell? The problem is that audio technology is a slippery subject and there is risk of misinformation both from the industry and from enthusiasts convinced of the value of things such as boutique cables or equipment supports, for which the benefits are hard to prove.
Lossless formats are a neat technical solution to the fact that uncompressed formats store data that humans cannot hear. There are compromises but the difference between Apple Music's humble 256kbps AAC and a lossless CD quality file is hard to hear.
In 2013, audio blogger Archimage conducted a survey to test the audibility of uncompressed audio versus 320kbps MP3 in a blind (unless you cheated) experiment so listeners did not know which was which. The result showed that that 52 per cent preferred the MP3, 30 per cent the lossless audio, and 18 per cent could not tell the difference.
No such experiment is definitive (particularly with only a small sample); it can always be argued that with a different selection of music, or different playback equipment, or different ears, the benefits of lossless audio will be revealed, but studies that demonstrate this are hard to find.
High-resolution audio is different from CD quality but how much of the additional data is audible? Very little, according to most studies, which is unsurprising. When bit depth is increased in PCM format audio, the potential dynamic range (the difference between the quietest and loudest sounds) increases, but even CD quality has dynamic range beyond the requirements of most music. When the sampling rate is increased the frequency response improves, but even CD quality at 44.1kHz extends to over 20kHz (half the sampling rate is the theoretical maximum), which is beyond the hearing range of most humans.
Audiophiles talk about required digital filters harming the sound, or high frequencies being perceived but not heard, but if there are differences, they are hard to discern and the details and "many little weird things" mentioned by O’Connell are not under threat. The audio transducers, microphones, and loudspeakers remain the largest source of distortion in the audio chain from studio to listener.
Listeners with wireless earphones will generally lose the lossless element in the final wireless connection. Many Bluetooth devices use SBC (sub-band codec) and manufacturers do not always bother with better (though still lossy) formats like Qualcomm aptX – because it is not the biggest factor in the perceived audio quality.
Talking of dynamic range, the music industry is also notorious for deliberately reducing it in order to increase the perceived loudness of recorded music. The idea is that louder music is more likely to be noticed and therefore streamed or purchased, never mind that it reduces the quality for discerning listeners.
Apple Digital Masters, formerly "mastered for iTunes", is a voice of sanity in that it emphasises mastering decisions above formats.
"Making decisions about gain levels, dynamic range, and frequency response is what mastering is all about," said its paper on the subject. "The highest frequency audible to humans is around 20kHz; therefore a sampling rate of over 40kHz is required to accurately capture the audible range of frequencies. Compact discs' 44.1kHz rate is adequate for this need."
Nevertheless, the company asks for high-resolution files from music producers because it then has the best source for encoding for AAC. Apple also said that "keeping the highest-resolution masters available in our systems allows for full advantage of future improvements to your or your client's music" so it has the capability to switch to lossless streaming in future.
Mulligan told us that in audio, perception is all-important. "People bought Beats headphones because of a perception of quality, even if the reality fell far shorter. In my opinion Spotify HiFi is more about branding than it is audio quality, and eventually everyone will follow suit." ®