The Fundamentals of Digital Music
Jack Shafton of GoldenEar Technology explains digital audio formats and how CE pros can educate clients who are becoming more interested in digital audio technologies.
It seems the transition from analog and physical media to digital music has happened overnight.
For the first time in 2011, music sales tipped in favor of digital media. Nielsen’s 2011 point-of-purchase (POP) figures indicate digital record sales grew almost 20 percent over 2010 numbers, while CD sales slipped just about 6 percent.
It’s imperative dealers who aren’t audio enthusiasts understand the world of digital audio and to have the ability to educate clients about music’s new delivery methods.
Educate & Stimulate
Most of the guidelines dealers use to sell home theater, whole-house audio and two-channel audio apply to digital audio system sales. Jack Shafton, VP of sales & marketing for GoldenEar Technology, says custom installers should approach the sales of digital audio gear by explaining the transition the market has made into the world of digital music.
Related: Creating a Digital Music Showroom
“Talk about the shift away from CDs, the development of iTunes and downloadable music and the digital audio market’s place in the music world compared to CDs and vinyl,” he advises. “Portable music ushered in exciting and amazing changes in how and where we listen to music. People love having their music available to them at all times. Streaming services and downloads from the Internet have allowed us to discover new music in ways we never imagined.”
Shafton says early portable music players relied on physical media sources like cassettes and CDs that limited their effectiveness. But as technologies improved, people were able to put lesser quality, low resolution audio files on solid-state and small hard drive-enabled devices and this fueled the market’s explosion.
Shafton says this paradigm changed the way people listened to music, particularly through the ability to easily pick and choose a song or build a playlist.
With storage becoming more affordable, Shafton says it is now easier for consumers to catalog higher-resolution audio files and experience a better way to listen to music.
What is High-Resolution Audio?
“High-resolution audio is generally considered to be that which is recorded or natively transferred from analog at higher than CD [level] resolution,” explains Shafton. “I think it is important to understand a bit of the technical aspects [of high-resolution audio] such as just how much data it represents and I think it’s instructive to start at the point of where we started: lossy, low-resolution audio.”
Here is how Shafton describes three common digital audio terms:
Lossy Audio: Looking at the lossless and lossy audio formats, lossless audio means what its name suggests - whatever the recording quality was, you have bit-for-bit data representation. Lossy audio formats use perceptual coding techniques to discard data in order to reduce file size and they allow users to store more music files in the same amount of space as a lossless file. The challenge for perceptual coders is to figure out what parts of the music are unimportant enough to throw away forever in order to reduce the file size but yet still sound like music.
CD Quality: As a baseline, let’s use lossless CD quality audio (44,100 samples per second at 16 bit depth, two channels). For clarity, the sample rate figure defines maximum recordable frequency (it is half the sample rate) and bits defines the maximum dynamic range available (defines dynamic range: 16 bits equals a theoretical maximum of 96 dB).
To quantify this, CD quality audio is 1411 kbps, or kilobits per second (44,100 x 16 x 2). The total of 1411 kbps is also called the bitrate. The lossy format 128 kbps bitrate that was defined in the lossy audio definition gives up a lot of quality. The math for a lossy format with a 128kbps bitrate is simple and it equates to the music missing about 91 percent of its original data.
There are much higher bitrate lossy files available to consumers. MP3 can go up to 320 kbps, which sounds immensely better than 128 kbps, but it’s still throwing away 77 percent of the original musical information.
High-Resolution Audio: Comparing high-resolution audio to CD is very similar to the lossless vs. lossy discussion, except lossy audio is CD resolution. Of course, it’s not really lossy but recording at 16-bit/44kHz levels doesn’t capture as much data as high-resolution does. High-resolution music is often available in three or four forms, with the most common being 24/96 and 24/192.
That means either 24-bit with 96,000 samples per second or 24-bit with 192,000 samples per second. 24/96 recordings can capture a little more than three times the data as CD resolution and 24/192 can capture nearly seven times the data as the CD format. While we may or may not be able to hear above 20,000 Hz (20kHz), there is a lot of musical energy at those levels of the hearing spectrum and high-resolution formats can capture all of that information.
Digital Music Playback Methods
Unlike the early days of true digital audio, there now are many ways to playback content. Starting with streaming audio from the web, consumers can listen to Internet radio stations such as Pandora, Rhapsody, Spotify and Last.fm. These web stations vary in sound quality, but the web offers an ever growing choice of stations that range in cost from free to services that are subscription only.
Bob is an audio enthusiast who has written about consumer electronics for various publications within Massachusetts before joining the staff of CE Pro in 2000. Bob is THX Level I certified, and he's also taken classes from the Imaging Science Foundation (ISF) and Home Acoustics Alliance (HAA). In addition, he's studied guitar and music theory at Sarrin Music Studios in Wakefield, Mass. Have a suggestion or a topic you want to read more about? Email Robert at [email protected]
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