In the last 15 years, as digital music has slowly but surely extinguished the analog flame, the focus with digital audio has always been on enabling easy access, portability, and manageability of the content. The MP3 format, and other compression codecs like AAC, Windows Media Audio, etc., have revolutionized the way music is distributed and consumed. These technologies took music from a physical format on CDs to one that could be stored or accessed on a digital player, tablet, phone, computer, or streaming device, making an enormous amount of audio available to consumers. The original Rio player, iPod, iPhone, PC, streaming devices, and the countless other devices that play and stream digital music have helped to transform the music and consumer electronics industries.
Along the way, however, sound quality has generally taken a back seat to advances in usability, the amount of content available, customizability of the music experience, and convenience of having your music whenever and wherever you want it. With the battle for supremacy now won, and digital music firmly entrenched in our lives, it’s now time to take the next step: It’s time to move from crappy MP3s and low-quality streams to high-resolution audio.
What is high-resolution audio?
What exactly is high-resolution audio? For the purposes of this discussion, the focus will be in hi-res audio for music content, not movies and video, because there is quite a bit of difference in how music and video is consumed. High-resolution audio has been available since the advent of the DVD and on Blu-ray discs with Dolby TrueHD and DTS HD soundtracks, but that’s a whole different discussion. This one’s about music, which in the digital world is mostly in non-high-res formats like MP3 and AAC.
High-resolution audio basics
The current standard for music encoding is 16-bit/44.1KHz encoding, which is the CD standard — originally created by Sony and Philips — that has been around since the early 1980s. Today’s MP3 and AAC tracks available on iTunes, Amazon, Google Play and other download stores are based on this encoding. All the popular streaming services like Pandora, Spotify, Slacker, and many others are also based on this encoding. Simply put, high-resolution audio is 24-bit/96KHz encoding, which is an analog wave sampled at 96,000 times per second, with each sample consisting of 24 bits (higher standards, such as 24-bit/192KHz, also exist). Generally, more bits equals more audio information captured, and should lead to better sound.
The other big thing to understand is lossless versus lossy formats. MP3 and AAC are referred to as lossy compression formats, which can get theoretically very close to CD quality at the higher bit rates for each (as in 320Kbps for MP3 and 256Kbps for AAC). Lossy formats use compression that throws away some of the encoded audio information, which tends to compress some of the dynamic range of the music. Formats like WAV, FLAC, AIFF, ALAC and others offer the ability to have lossless compression for audio content. Some of these, like FLAC and WAV, support 24/96 and higher audio encoding. Another high-resolution format is DSD (Direct Stream Digital, invented by Sony and Philips for the Super Audio CD format) which samples analog waves at a much higher rate (2.8224MHz) and stores it in 1-bit samples.