Sunday, Blur headlined a Hyde Park concert marking the end of the London Olympics. For fans who want to remind themselves of Blur’s heyday, the band’s back catalogue has been reissued in the Mastered for iTunes format, a new initiative from Apple that promises higher-quality digital downloads. Blur’s seven studio albums should sound better than ever.
The music downloading era kicked off with MP3, a data-compression format that reduced the file size of audio tracks to make them small enough to download over the Internet while retaining as much of the original recording as possible.
The algorithms behind MP3, Apple’s AAC and other compression formats are designed to remove frequencies that most people won’t be able to hear anyway. But they are still “lossy” and some quality is sacrificed so that file sizes stay small.
Mastered for iTunes is driven by a series of guidelines from Apple to help producers to make their tracks sound as good as possible before submitting them. The theory is simple: start with the highest-quality audio before compression and you should get better sound afterwards.
There are three terms to understand about digital audio: bit depth is the number of bits of information recorded each time the music is sampled; sample rate is the number of times the information is sampled each second; and bit rate describes the amount of data transmitted per second.
A compact disc has a bit depth of 16, sample rate of 44.1kHz and a 1.4Mbps bit rate. Apple wants record labels to supply 24-bit, 96kHz files, which encompass a dynamic range beyond the hearing capability of the human ear. The aim is to compress those files to CD quality while retaining as much detail as possible. The end result, Apple says, is an improved 256kbps AAC file.
One record label that has embraced Mastered for iTunes is LSO Live, the London Symphony Orchestra’s record label. James Mallinson, LSO Live’s producer, says Apple has “come up with algorithms that seem to do a better job of keeping the right stuff than anybody else has”.
He says that although the human ear can’t hear much above 22kHz — a level that declines with age — it doesn’t follow that frequencies above that level are irrelevant.
He argues: “The missing high frequencies affect the way you perceive the lower frequencies. In other words, the ear is a much more complex organ than people thought it was. That is one of the problems with CD: there was a complete cut-off at 22k. That’s not enough for your ear. Even though you can’t hear a 22k sine wave, you need those higher frequencies there.”
Mallinson adds: “One of the things that Mastered for iTunes has done is find a way of incorporating those higher partials into the file that ends up on iTunes.”
Sampling theory is an extraordinarily complicated field — just mention the Nyquist-Shannon sampling theorem to an expert and prepare to be bewildered for an hour or so. There is widespread disagreement about how much can be removed from a piece of music without affecting quality, the extent to which playback equipment affects quality, the listener’s position and even the concept of “better” or “worse” audio quality itself.
Neil Young, the rock star, campaigns loudly for music to be released in even higher quality. He wants 24-bit, 192kHz files to be available. It is worth remembering that Young is something of an obsessive: he once wired up his house as a left speaker and his barn as the right and listened to music from the middle of his lake.
Chris Montgomery, the creator of the Ogg Vorbis compression format, is dismissive of Young’s campaign. This year, he wrote: “There are a few real problems with the audio quality and ‘experience’ of digitally distributed music today. 24/192 solves none of them.”
That hasn’t stopped the high-end audio manufacturer Linn, which has been selling 24-bit, 192kHz files of its own recordings for a while and this year added albums from Universal records to its store. Gilad Tiefenbrun, Linn’s managing director, is embracing high-quality downloads. He says: “Once you increase the headroom — the potential of the sound — there is the incentive for audio engineers to up their game. The quality of our recordings over the past few years has improved exponentially.”
Where digital audio files were once listened to mostly through earbuds on MP3 players or cheap computer speakers, they have now reached the living room. Linn’s range of network music players, though not cheap, are designed to play your music and connect to your television, Blu-ray player or even stream from iPlayer.
Sonos, an audio manufacturer that specialises in wireless, multi-room sound systems, is similarly primed to take advantage of rising audio quality. The company’s Tom Lodge says: “Now most of the decent services are offering audio quality that is worthy of being listened to on a hi-fi system.”
For Blur fans who have worn out their vinyl copy of 1993’s Modern Life Is Rubbish, digital downloads might soon be able to offer an experience that is just as good. Modern Life might not be that bad after all.