High-resolution digital audio is up and coming, offering better sound quality than your CD collection. Here's everything you need to know about hi-res music: how to buy it and how to optimise your PC to enjoy all the detail it has to offer.
As we explain in our guide to getting better quality audio from your PC, MP3 files created from your CDs or bought online, offer lower quality than the original recordings. Even if you've already ripped your CD collection to lossless 16-bit/44.1kHz FLAC or ALAC files, you're still missing out on the best quality available: high-resolution digital music tracks in 24/96 or better.
High-resolution or 'hi-res' digital music is considered digital audio recorded at 24-bit/44.1kHz or better. But for most listeners, it’ll need to be 24/88.2 or higher, with the most common options found today being either 24/96 or 24/192.
Hi-res music has been commercially available since the introduction of DVD video in 1997. At the turn of the century there were also plans to replace the CD with a high-resolution music disc, based on the higher-capacity DVD format, although two incompatible systems actually appeared leading to a format war between them – the Super Audio Compact Disc (SACD) and DVD-Audio (DVD-A).
Both formats effectively lost, with consumer demand for ‘free’ and ‘easy’ leading to the supremacy of worse-than-CD music formats like MP3 and AAC. More recently, audio enthusiast have been able to rip SACDs by using hacked Sony PS3 consoles. But the music files on these disc are in an unusual format, Direct Stream Digital (DSD), which requires special software and capable hardware to play.
How do I get high-resolution music?
However in the last couple of years, internet-based music stores and specialist recording labels have slowly started offering hi-res digital music downloads. These include HDTracks, Linn Records, Naim Label and Bowers & Wilkins.
You can buy high-resolution albums in various digital formats such as FLAC, WAV, ALAC and AIFF for download onto your computer ready to be played. High-resolution 24-bit files are more expensive to buy than 16-bit CD-quality files, by varying amounts. We found it was possible to get the 24-bit versions for about 30 percent more.
You’re unlikely to find many top 40 albums on offer, as the big labels are quite protective of their hi-res studio masters and have offered only very limited numbers of high-res tracks on these sites. If your music taste leans towards jazz, blues and classical, you should find plenty of choice, though.
What will I need to play HD audio files?
You can play high-res audio files on most PCs, in iTunes or using Windows Media Player with suitable codecs, but better results are usually found with specialist software such as Audirvana Plus, J-River or Bit-Perfect. You will also need to check that your PC is set up correctly in its audio preferences, to ensure music isn’t down-sampled to CD quality again.
A good music system helps you enjoy hi-res music even better. Using your PC speakers alone to listen to these files, you’re less likely to hear the differences. You can compare this to using an old TV set to pay Blu-ray films; yes you can watch them but you're not getting the full HD experience.
Specialist audio companies – many of them British-based companies such as KEF, B&W, and Cambridge Audio – sell hi-res capable active speakers that plug into your PC or laptop via USB, and can support audio to at least 24-bit/96kHz quality. See also: KEF X300A review
If you already have a decent hi-fi music system and good speakers or headphones, you might only need a digital-to-analogue convertor (DAC) that supports hi-res audio. Most USB outboard DACs support 24/96 audio, while the better units now also support 24-bit/192kHz files.
Look out for those that support synchronous-mode USB, as these far exceed the sound quality available from older USB audio devices that relied on the PC’s digital audio clock in adaptive-mode USB.
Besides playing your high-res files from your computer, there are now many easier options available – the most popular is the audio streamer, such as the Chordette (right). These range in price from a few hundred to several thousand pounds, and usually have a built-in DAC or can be bought as a complete mini hi-fi system (just add speakers).
Playback can be as simple as plugging in a USB stick, loaded with your 24-bit high-res music to play. Or slightly more complicated but vastly more convenient when working properly is to play your music from a Network Attached Storage (NAS) drive through your home network. This allows you to serve all your music files to the streamer, wired or wirelessly, controlling playback via an iPad, iPhone or Android device. See also: Synology DiskStation DS213 review
If you’re after a more portable setup, there are now several players that are hi-res-capable. Astell & Kern, Sony and Fiio - to name a few - make iPod-sized players, while some smartphones are beginning to support hi-res audio. LG’s G2, for example is capable of playing 24-bit, 192kHz music in FLAC or WAV format. Remember that a good pair of headphones will be crucial to get the best out of high-res audio here.
So is HD audio all worth the cost and hassle?
Hi-res 24-bit audio should have a clear advantage in sound quality over CD-quality audio and is a major upgrade to more common low-res MP3. Music will become more involving and alive. Instruments will sound more natural and will be more separated from each other in busier sections of music, rather than confused and congested together. The bass will seem to be go lower and the treble will be cleaner and less tiring to listen to.
But – and there is a but - the most important factor remains how well the music has been recorded and mastered in the first place. Many albums today are mixed to sound good on low-quality headphones and car stereos. These mixes all too often include dynamic compression to make them sound ‘loud’ and more impressive. And in doing so lose all the subtleties of the original recording. Even though you might have an album in 24-bit format, it might sound little better than the CD version.
The good news is that many internet-based hi-res audio stores do provide sample files, so that you can download and try them for free first to see if you can hear a difference.