High resolution downloads are changing the way we enjoy music, opening up possibilities undreamed of back in digital’s early days…

It’s hard to understate the impact that Compact Disc made, upon its introduction back in 1982. At the time, the music world was very different, with vinyl regarded as the only serious way to play music. Found everywhere from broadcast studios to the local youth club, LPs were the world’s favourite music format. Still, at over thirty years old, black plastic was knocking on and sales were on the wane, down 40% from its 1975 high watermark. The scene was set for the brave new world of digital audio…

What music lovers needed now was a small, convenient, high quality music carrier, and CD was it. Hailed as a miracle of modernity, it fused two technologies – a digital audio coding system developed by Sony, and a laser optical disc storage system developed by Philips.

Legend has it that Sony had wanted the new ‘Digital Audio Disc’ to be 12 inches wide, just like an LP, as they were worried that album artwork wouldn’t look good on Philips’ proposed 5″ disc.  Philips had wanted cardboard sleeves, just like LPs, but Sony insisted on a plastic ‘jewel case’ to give the product a more tangible feel. So when CD finally emerged, it was full of compromises limited by the technology and what the big companies thought the public wanted.

SOUND AFFECTS

Given that the average early eighties turntable could scarcely spin at the right speed, the new digital disc was a revelation. Sonically CD was was streets ahead of most people’s vinyl experience – and had the added benefit of being immune from surface noise, static crackle and disc wear too. There were some golden eared hi-fi hacks around who didn’t like its sound, describing it as a little stark and two dimensional. But by and large, CD was a quantum leap forward…

Despite Philips’ famous description of it as giving “pure, perfect sound forever”, people soon started noticing problems however. Compared to analogue, early 16-bit digital could sound spiky and hard, giving cymbals and female vocals a coldness that just didn’t seem right. Lab measurements showed that whilst CD’s 16-bit digital system gave very low distortion on the loudest parts of the music, it distorted heavily on the quieter bits – the exact opposite to how analogue LP behaved. Worse still, the digital system was prone to distorting most in the upper midband and treble, just where the ear is most sensitive…

This was down to the way digital audio encodes the analogue musical waveform, and it applies to every format that uses the Pulse Code Modulation digital system, such as CD, MP3, AAC and FLAC. With PCM, the two basic factors that determine the sound quality are bit depth (which determines the quality with which the analogue signal is digitised), and the sampling frequency (which is the number of times per second that the analogue signal is digitised). CD is a 16-bit, 44.1kHz system, giving a frequency response of 5-22,000Hz and 96dB dynamic range.

A good analogy is radio sound quality. The sound of AM radio can be likened to digital systems running low sampling frequencies (giving a rolled off treble) and low bit depths (making for a coarse and flat sound lacking in detail and subtlety). FM radio, with its more extended treble and smoother, more sophisticated sound can be compared to a high resolution digital system. As the bit depth increases, you get a deeper and more delicate sound, and as the sampling rate rises, you get a wider frequency range.

The graph above shows the difference in the way a real sine wave looks on an oscilloscope, and how a low resolution digital approximation of it appears – you can see how the latter is simply unable to trace the analogue waveform smoothly. So the more bits you use, the more natural the music sounds, and the faster the samples, the wider the frequency range. CD’s 16/44.1 digital system was state of the art in 1982, but it didn’t take long for it to get past its sell-by date.

Malcolm Hawksford, Professor of Psychoacoustics at Essex University, reckons that, “CD’s digital specification was almost good enough for audiophile music reproduction. It was near the limit, but in my view probably a bit marginal. Ideally, at least 20-bit resolution at 60 kHz sampling frequency would have been better”.

BIT BETTER

Compact Disc became a technological time trap for audiophiles. Its almost-good-enough digital specification put the development of digital in suspended animation, locking us in to an outdated nineteen eighties way of digitising music. No surprise then that in recent years, many hi-fi purists have been turning back to vinyl which – being analogue – offers almost infinite levels of resolution. “Analogue audio systems are limited not by digital bits, but atoms,” argues Hi-Fi World magazine’s Paul Rigby. “Where LP record playback fails is in the mechanical tolerances of the playback equipment, such as bearing friction and so on, rather than the resolution of the format itself. With digital though, it can only be so good and no better.

Happily, DVD-Audio and Super Audio Compact Disc (SACD) arrived at the end of the nineties to save the day, offering far superior sound to CD. With the former offering true 24bit resolution, it came over as punchy and powerful with tremendous detail, plus a wonderfully smooth low distortion sound right across the audio band.

“I have seen some really good recordings over the last decade where 16-bit was just not enough to hold all the information,” says B&W digital research engineer Albert Yong., “and given the opportunity to then listen to those recordings in 24-bits, they just blew the 16bit version out of the water”.

Although 24-bit DVD-A sounded superb, it never got off the ground commercially. It was expensive, you needed a special type of DVD player and most importantly of all, retailers simply didn’t want to sell it. With DVD video discs making the stores a mint (at the time), there was no reason to devote shelf space to less commercial audiophile music releases. DVD-Audio’s life was over just a couple of years after its inception, and no one missed it except a select bunch of audiophiles who’d heard 24-bit digital and couldn’t go back. But, whilst the disc went the way of the Dodo, its coding system would live on…

Just as DVD-A’s sun was setting, so digital file downloads began making great inroads into the music marketplace. The MP3 format was no great shakes sonically but it was only the first wave; it might have sounded bad, but it ushered in a new way of obtaining music that no longer had any limits. Whereas CD was frozen in time and space, committed to its dated 16-bit, 44.1kHz flavour, internet distributed music could arrive in a way that suits the artist, label and listener.

Enter Free Lossless Audio Codec in 2001 – which was an altogether more intelligent way of encoding music. Rather than the compressed system that MP3 used  which reduces file sizes by about 80% by cutting out most of the music you can’t hear (and some that you can), FLAC used a clever ‘lossless’ packing system that doesn’t remove any music at all, and saves about 30% to 50% of space. “It’s a problem-free system,” says Professor Hawksford, “if the arithmetic is performed correctly and the compressed files are not corrupted then there are no errors in the reconstructed output.”

Whilst we’ve seen a number of lossless systems, from Apple Lossless (ALAC) to Windows Media Audio Lossless (WMA Lossless), the Free Lossless Audio Codec (FLAC) has emerged triumphant for music-loving hi-fi buffs. The spiritual successor to MP3, it’s an open-source system that’s not tied to any one manufacturer, which explains it success. Better still, it comes in more than one resolution. Whilst you can encode your CDs to FLAC keeping their 16-bit, 44.1kHz resolution, FLAC can also come in 24-bit form too. “The system is so flexible that it can take anything from 4 to 32 bits and sample rates up to 655350Hz in 1 Hz steps – it can certainly replace 24/96 DVD-Audio”, says Albert Yong.

BETTER THAN CD

Compared to the mastertape, CD gives a decent but unsophisticated facsimile. Its 16/44.1 specification boasts a dynamic range of around 96dB, which is ample for most music work. The trouble is though, the quieter the signal is, the more the system distorts using the PCM digital system, which effectively sucks out the atmosphere – all the subtle ambient details – of a piece of music. In a direct A-B comparison with the mastertape, “16-bit sounds slightly vague,” says Paul Rigby, “like a primitive digital camera it simply loses the subtlety and fine detail; it’s less easy to live with than hi res digital”.

Theoretically, 24-bit digital has a resolution of 144dB, which is more than enough (130dB is the threshold of pain for the human ear), but the problem is, as Professor Hawksford notes, of actually finding studios capable of recording at anywhere near this resolution. “Not many recordings fully exploit the capabilities of CD, let alone higher resolution formats”, he notes…

Bowers &Wilkins’ Albert Yong agrees that we’re a good way away from achieving true 24-bit masters, but still we can do much better than old fashioned 16-bit, and people can easily hear the difference.

“We have seen some extremely good recordings lately, when the entire recording chain is done right. We can potentially get up to around 20 to 22 bits at the moment, and they do sound a lot better. The difference is in the detail. Sounds generally are more open, and there is an extra level to airiness to the music. Voice and instruments sounds closer to live, and more dynamic as well”.

THE MECHANICS

Like any other music file, you can either ‘rip’ FLAC copies of your existing CDs, or download load them from music sites such as Society of Sound. We’ve structured our site to make downloading FLAC a breeze. After you’ve logged into the download manager it’s simply a case of choosing an album and downloading the format you want. You can choose which folder the music goes to using the Settings within the app and then simply pull into your player.

If you’re looking to build up a FLAC library of your existing CD collection, then a good starting point for ripping is Exact Audio Copy or dBpowerAMP. These are freely downloadable applications for Windows, commonly thought to be the best sounding and most bug-free. Mac Users can try Max or MacFlac.

Once you’ve downloaded your FLAC music, or ripped it from CD using the aforementioned applications, you’ll need to play it. Currently, neither Microsoft’s Windows Media Player or Apple’s iTunes support FLAC without modifications.

If you wish to import FLAC files to iTunes on MacOS we recommend you try a program known as Max for MacOS X 10, which can convert and rip PCM files and import them to your iTunes library. For more information please see here.

Both Windows Media Player and iTunes have their own equivalents (WMA Lossless and Apple Lossless respectively) but these are tied to the operating system providers, whereas FLAC is of course a free, open source system like MP3. So for Windows-based systems, we recommend you download Winamp which is a highly flexible media player that also supports burning 16-bit formats to CD. There are other media players you may wish to try such as Songbird, Media Monkey and Foobar2000, which is generally agreed to be the best sounding on the Windows platform. When you start up your music player, it should automatically search for all your digital music and add it to the library. SongBird will even go online and look for the artwork too, just like iTunes or WMP. which is a slick player for both Windows and Mac, with a nice clean interface.

Through their bundled music players, both Microsoft and Apple have chosen to support certain file formats (WMA and AAC respectively). Whilst these players offer some flexibility (they both play MP3, for example), they’re both committed to their own Lossless formats. so FLAC is excluded. However, there are now ‘bolt on’ FLAC players for iTunes.

Fluke is freeware that works as ‘plug in’ for iTunes (Mac platform), but can be buggy. Amarra Mini by Sonic Studio is a more sophisticated system that piggybacks on to iTunes, replacing much of its audio code with a superior sounding and more flexible system. Sound is excellent but you pay for it; the basic Junior version which gives FLAC playback up to 24/96 starts at $99.

Audirvana Plus (www.audirvana.com) is another fine application that, like Amarra, shuts down certain parts of your computer to minimise drain on CPU resources, to (so the theory goes) give better sound. There’s a free trial download but you’ll have to pay $49 for the full version. It now offers optional integration with iTunes and is a strong, stable performer. For Mac users, its combination of value and performance is currently hard to beat.

It’s easy to burn 16-bit FLAC files on to a CD-R for playback in a conventional hi-fi or car CD player.  Winamp is a free player which also supports burning FLAC16 files to CD. If you wish to use a proper CD authoring software, then Roxio RecordNow MusicLab 10 Premier (Windows, $49.99) or Roxio Toast 11 Titanium (Mac. $99.95) are worth considering because the standard Windows or Mac music players won’t handle FLAC, either 16 or 24-bit.

Once you’ve got your 24-bit FLAC files and FLAC player; now it’s time to get the music out to your ears. There are several ways of doing this:

• The simplest is to take an analogue line output from your computer soundcard. This is likely to have a 3.5mm mini-jack plug; we recommend a high quality bespoke cable such as Chord’s iChord for around £30. Although it will give a decent sound, particularly if you have a good quality soundcard, it is not ideal because computers are electrically ‘noisy’ environments, and it is best if at all possible to pipe out the digital signal away from the PC or Mac.

• A dedicated USB DAC like HRT’s Music Streamer II (£160) gives excellent results, and connects up as simply as a digital camera; just plug the USB lead into the computer at one end and the HRT into the other. It will stream digital music at up to 24/96 resolution through its RCA line level analogue phono outputs (which connect into the ‘Aux’ input of your amplifier) and it sports an asynchronous USB connection, so the high quality clock onboard will control the computer’s digital datastream. This gives tighter, smoother sound compared to standard asynchronous USB, as a result of lower jitter.

• If your PC or Mac has a digital output, you can run a good quality optical or coaxial lead into a modern digital convertor such as an Arcam rDAC (£300) and you have a proper, high quality 24-bit FLAC playout system, that will give superior sound to many CD players. It’s important to note here that Windows users should download the latest ASIO drivers; these provide a ‘source direct’ function, ensuring the digital datastream goes direct from the FLAC software player to the USB digital output. Many of the latest DACs, like the Arcam rDAC and Cambridge Audio DAC Magic Plus (£350), also have USB inputs that can be driven directly from computers.

• Wireless streaming is the third, and for many the preferred option. Logitech’s Squeezebox Touch (£259) is one of the most inexpensive and convenient ways of getting full 24-bit FLAC replay at up to 96kHz sampling rate. It comes with bespoke playback software that lets your computer control it via your home wireless network, giving an iTunes-style user interface. Generally, these work very well and are an excellent way of giving multiform functionality. Although it has built-in line level analogue outputs which are ideal for use in a second system, again audiophiles should use its digital output into a hi-fi DAC, such as the aforementioned Arcam rDAC or Cambridge Audio DAC Magic. For even better sound at a slightly higher price, the £500 Rega DAC is hard to beat at or anywhere near the cost.

• For those with more money to spend, there’s a whole host of network music players, from the Cambridge Audio NP30 (£400) and Musical Fidelity M1 CLiC (£1,300) to Naim’s NDX (£3,000) and Linn’s Akurate DSM (£5,600). These are all excellent products at their price; the more money you spend, the better. Also, the more expensive they are, the less the need for a separate DAC; the Naim and Linn deliver superb results out of the box. It all depends on how far you want to take your networked music; whether it’s just another handy way of playing your favourite tunes, or a purpose-designed no-compromise system to eke out the very best from digital.

You can also check our recent 24-bit blog post to see how fellow audiophiles listen to 24-bit FLAC

THE EDGE

There’s an old maxim in the hi-fi industry, borrowed from the early days of the computer pioneers – “garbage in, garbage out”. Any speaker can only be as good as the system driving it, and any system is limited by the quality of the original source material. That’s why B&W, as a manufacturer of premium, leading edge loudspeakers, takes FLAC very seriously. In 24-bit form it’s the modern day incarnation of digital’s finest hour, DVD-Audio, but even better because it’s almost infinitely upgradeable and future-proof. Professor Hawksford gives it the nod. “FLAC has a place in the future for high quality audio. It is good for transporting files on the Internet as it typically halves download time. It is unlikely that for lossless compression there will be significant improvements”, Hawksford believes.

The ease with which it can be delivered to a computer means that anyone who’s capable of sending their friend a digital photo can now download and play high resolution FLAC files, and the benefits are clear for all to hear.

“FLAC is as good as it can get for now. I think what it brings is not limited to quality of audio, but the added convenience as well”, says B&W’s Albert Yong. The only drawback is the sheer scarcity of quality recorded music in 24-bit FLAC format, and that’s where Bowers & Wilkins’ Society of Sound comes in.

Meticulous attention to detail across the whole recording process with the latest high resolution digital recording systems, makes for music of unalloyed purity. That’s why we’re so keen for you to experience 24-bit for yourself. Download Portico Quartet’s Ruins in 24-bit stunning quality.

DIGITAL TIMELINE

1841     Augustin-Louis Cauchy first proposed sampling theory.

1928     Harry Nyquist presents sampling theory to the American Institute of Electrical Engineers

1937     Reeves proposed pulse code wave modulation (PCM) as a way of storing audio

1948     John Bardeen, William Shockley and Walter Brattain’s bipolar junction transistor, which made compact digital circuitry a reality.

1958     C.H. Townes and A.L. Shawlow invented the laser.

1960    I.S. Reed and G. Solomon’s work on error correction codes gave us the technology that would be directly applied to Compact Disc twenty two years later

1967     Japan’s NHK Technical Research Institute publicly demonstrates a digital audio recorder running 12bit resolution and a 30kHz sampling rate.

1969      Physicist Klaas Compaan uses a glass disc to store black and white holographic images using frequency modulation at Philips Laboratories.

1977     Sony, Mitsubishi and Hitachi demonstrate digital audio discs

1980     Sony signs up to Philips ‘Red Book’ laser disc; Compact Disc is born.

1982     Sony and Philips launch first commercial CD players.

1987     Sony launches Digital Audio Tape (DAT) with 16-bit, 48kHz digital PCM system.

1994     MP3 (MPEG 1 Audio Layer 3) finalised. A compressed, lossy 16/44.1 format using approximately 20% of the space of a WAV file, it ushers in online music  distribution.

1999     Super Audio Compact Disc (SACD) launched, offering high resolution digital sound using the Direct Stream Digital (DSD) system, with effective 20-bit resolution.

2000     DVD-Audio is launched from the DVD-Forum; offering up to 24-bit, 96kHz resolution from a DVD.

2001     Josh Coulson finalises Free Lossless Audio Codec (FLAC) v1.0.