What is high-resolution audio?
Before we address this, it’s worth pointing out that the definition of high-resolution audio isn’t set in stone. Unlike high-definition video, which has to meet certain criteria to earn the name, there’s no universal standard for high-res audio.
But it tends to refer to audio that has a higher sampling frequency and bit depth than CD, which is 16-bit/44.1kHz. High-resolution audio files usually use a sampling frequency or 96kHz or 192kHz at 24-bit, but you can also have 88.2kHz and 176.4kHz files too. Sampling frequency means the number of times samples are taken per second when the analogue sound waves are converted into digital. The more bits there are meanwhile, the more accurately the signal can be measured in the first place, so 16-bit to 24-bit can see a noticeable leap in quality.
The Digital Entertainment Group, Consumer Electronics Association and The Recording Academy have, together with record labels, come up with a formal definition for high-res audio. As well as the definition – “Lossless audio that is capable of reproducing the full range of sound from recordings that have been mastered from better than CD quality music sources” – there are four different recording categories based on the source of the file.
There are several high-resolution audio file formats to choose from, all of which support the above sampling rates and bit-depths. They include FLAC (Free Lossless Audio Codec) and ALAC (Apple Lossless Audio Codec), both of which are compressed but in a way that (in theory) no information is lost. Other formats include WAV, AIFF and DSD, the format used for Super Audio CDs. The relative merits of the formats can be argued but most crucial will be compatibility with your particular products and system.
FLAC tends to be the most popular, scoring points over WAV for better meta-data support, ensuring your tracks have artist and title information. There’s a healthy debate on the What Hi-Fi? Forum on the subject of FLAC vs. WAV. Of course, as well as downloading your music in these superior formats, and now streaming, you can – and should – also rip your existing music library in these higher-quality file formats.
What’s so good about high-res audio?
Obviously the main claimed benefit of high-resolution audio files is superior sound quality over compressed audio formats. To illustrate why they should sound better than MP3s, for example, let’s compare the relative bitrates. The highest quality MP3 has a bitrate of 320kbps, whereas a 24-bit/192kHz file is transferred at a rate of 9216kbps. Music CDs are transferred at 1411kbps. 24-bit/96k or 24-bit/192kHz files should therefore more closely replicate the sound quality that the musicians and engineers were working with in the studio. With more information to play with, high-resolution audio tends to boast greater detail and texture, bringing listeners closer to the original performance.
Where to buy and download high-res audio? Here are a few of the best:
Pioneering US high-resolution music store HDTracks is now available in the UK, initially launching with more than 10,000 uncompromised high-resolution albums. The company says it has partnered with every major record label – including Sony Music Entertainment, Warner and Universal – to create the world’s largest catalogue of high-res audio files. HDTracks has also announced a deal with Liztic, a music management application that aims to deliver a seamless digital music experience across PC, Mac, Android and iOS.
Better known for its home entertainment systems, Naim has a nifty sideline in hi-res audio files, including music from its own Naim Label. Its site offers music in 320kbps MP3s right up to 24-bit/192kHz WAV, FLAC and ALAC files. High-res albums cost between £9.99 and £16.99.
Linn’s website offers what it calls Studio Master downloads in 24-bit/192kHz FLAC and ALAC, as well as 24-bit/96kHz, 16-bit/44.1kHz and 320kbps MP3 formats. A Studio Master album costs £18, or £10 in CD quality.
Another hi-fi brand that turned its hand to hi-res downloads, B&W’s site boasts a range of studio-quality albums. You can also subscribe and access albums not available in the store. Files are available in 24-bit and cost £15.
Neil Young’s long-awaited Pono high-res service looks finally set to launch, with news that a Kickstarter campaign will make the PonoPlayer available to buy. The PonoMusic service promises DRM-free high-res downloads from major and independent labels and there’s a dedicated music management software application, too. You can read our first impressions of the Pono PonoPlayer for more details.
French website Qobuz launched in the UK back in August and offers in excess of 20,000 high-resolution albums. Files are available at a minimum of 16-bit/44.1kHz while many are offered in 24-bit/192kHz. High-resolution files are also available through the Qobuz streaming service.
Building on the return of the brand in the form of new AV products, Technics has also launched a download store, complete with high-resolution music. The store claims ‘tens of thousands’ of tracks are available.
2L – Norwegian site offering up to 24-bit/96kHz and multichannel DSD
7Digital – Offers 24-bit FLAC downloads
Gimell – Studio Master 5.1 downloads in 24-bit/96kHz
HD Klassik – Classical music high-res downloads
Sony, Warner and Universal have also announced that they will make their extensive music catalogues available to hi-res download services – all of which is a real shot in the arm for fans of high-resolution audio in this country. With all sites, make sure it’s clear what file format and bitrate you are buying and let us know your experiences with using these and any other HRA websites in the comments below.
Tidal and Meridian demo high-res streaming We’ve now seen the launch of CD-quality streaming services, with Tidal and Qobuz launching in to the market offering lossless audio streams. This delivers a step-up in quality over the established services such as Google Play Music, Rdio and the market-leader, Spotify. And indeed the new Apple Music streaming service. But it’s not strictly high-res audio, which refers to better-than-CD-quality files. There is one exception – if you have an Android phone you can stream high-res audio on Qobuz.
Tidal and Meridian have also successfully demonstrated streaming high-res audio, using Meridian’s MQA format. But there’s no sign of an official public launch yet. It could be that Meridian’s MQA format is key for any further high-res streaming services.
What do I need to play it?
From AV receivers and stereo amps to all-in-one music systems and streamers, a growing number of products on the market are handling high-resolution audio. As yet, there remains a certain amount of variation when it comes to file handling and maximum bitrate support on different devices, so check the specifications match your requirements before you buy a new product. Some systems allow you to play high-res files directly from USB storage devices or from a networked PC via Ethernet.
You can also play high-resolution audio stored on a PC by connecting it to a USB DAC like the the AURALiC Vega, Peachtree Audio’s portable DAC “Shift” or any of the Peachtree Audio Integrated amplifiers and many others, then feeding it to a power amp, powered speakers or headphones.
Complete systems, such as the AURALiC , now support high-res audio (as well as wireless streaming features), while companies such as Sharp have also got in on the act.
You can even buy dedicated headphone amps with built-in DACs that handle high-res audio. The ever-popular Sonos system supports WAV and AIFF files but only up to uncompressed CD quality or the HiFiMan: HE6, EF100, or EF2C. However, you will need a high resolution audio player, as not all music software is compatible. iTunes will play high-res files but not FLAC files, for example.
High-res music on mobile
High-res audio isn’t just confined to the hi-fi market. Several of the latest smartphones play music in sparking 24-bit/192kHz quality, including the LH Labs, Peachtree Audio Shift, LG G3, Sony Xperia Z3 and Samsung Galaxy Note 4, while the Onkyo HF Player app allows you to play high-res music on any compatible mobile phone.
The iPhone 6 sadly doesn’t support high-res audio out of the box but there is the potential to connect devices via the Lightning output rather than the headphone jack to send a digital audio signal. This is where you would connect the LH Labs GeekOut V2, Peachtree Audio Shift and other similar products.
The Philips M2L headphones are the first to use the Lightning connection, bypassing the iPhone’s internal DAC to instead use their own high-res capable DAC. And Qobuz has provided a world first for Android mobile users: the ability to stream high-res music on your phone via its streaming service.
Since receiving its own dedicated zone at CES, high-resolution audio gained a lot of traction in 2014 and in to 2015. Manufacturers including AURALiC, LH Labs & Peachtree Audio have been pushing for and producing high-resolution audio products for some time. We’ve now see mass-market heavyweights such as Sony, LG and Samsung adopt the format to bring it to a larger audience. With this wider availability, more people are able to learn and understand exactly what high-resolution audio is, and the benefits it brings to music listening. There’s plenty of content out there – and now we have the hardware to go with it. Moving through 2015, we expect more manufacturers to produce more affordable high-res audio products, as high-res becomes a standard feature on music players, streamers and more, giving consumers the choice to get involved, should they value the potential jump in audio quality.