A Glossary: Hi-Res Audio | Music Terms & Definitions

There are simply too many different definitions, misuse of terminology, and hype happening in the high-resolution audio and music marketplace. How is a novice audio consumer supposed to wade through the confusion when the “guides” being provided by the authorities are full of mistakes? You really have to wonder about their motivations or their knowledge when the material they issue falls so far short of the truth.

So here’s a partial glossary to help guide consumers…think of it as a defense against the marketing machine that’s about to hit you as you shop this holiday season. This is not meant to be comprehensive. I’m preparing a more thorough glossary for my “High-Resolution Audio | Music: A Reality Check” retailer and consumer guide to the subject (which is part of the next stretch goal for the Kickstarter campaign). The terms below are presented in stark contrast to others that I’ve seen.

Analog Master: A recording made using analog methods including cylinders, lacquer and vinyl discs, wire recorders, and analog tape. Analog masters of older recordings and a minority of new projects recorded on analog tape are routinely used as sources for “hi-res” music files. However, the fidelity of the original analog source is not enhanced by conversion to a digital format in spite of the “hi-res” label. Whatever the fidelity of the source will be transferred to the new digital file…there is not improvement in the fidelity of the new digital file.

Compact Disc (CD): Produced according to the Redbook specification, a compact disc is 12 cm diameter, 1.5 mm thick, optical disc capable of storing digital audio encoded at 44.1 kHz/16-bit using PCM (Pulse Code Modulation). This standard is incorrectly referred to by many as “CD Quality”, which actually refers to any digital file that consumers agree sounds “as good as a CD”. Compact discs have the potential to provide very good fidelity if the engineers, producers, and mastering engineers chose to maximize fidelity.

Compression (Audio): Compression is a term that can be have two completely different meanings in audio. When used by audio engineers during the production or mastering stages of a project, it refers to the automatic reduction of audio amplitude levels (attenuation) by means of analog or digital processors. For example, if a vocalist has a very wide dynamic range, a compressor would be able to smooth out the amplitude variations resulting in added vocal presence and volume. During mastering, a particularly aggressive type of dynamics reduction called “limiting” can virtually remove all natural musical dynamics.

Compression (Data): This type of compression reduces the size of a data file. Think ZIP files for transmitting data (of any sort) from one place to another…when unzipped, all of the original data is restored. For audio, data compression reduces the size of the source file according to two different schemes.

Lossy Compression: Examples of lossy data compression types are MP3s, AAC, and AC3, which are capable of reducing the size of a file but fail to retrieve all of the original fidelity upon playback. Some data is lost in the reproduction of the compressed audio file.

Lossless Compression: Examples of lossless data compression types are FLAC and MLP, which are capable of reducing the size of a file and maintain all of the original fidelity upon playback…bit for bit accuracy. None of the data is lost in the reproduction of the compressed audio file.

To be continued…


I’ve added a second stretch goal to the Kickstarter Campaign. Check it out by clicking here.


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

6 thoughts on “A Glossary: Hi-Res Audio | Music Terms & Definitions

  • October 12, 2015 at 12:09 am

    “Lossless Compression: Examples of lossy data compression types are FLAC, MLP, and MQA, which are capable of reducing the size of a file and maintain all of the original fidelity upon playback…bit for bit accuracy ”

    Mark, Please don’t be offended, I know you have to rush a lot to produce this blog every day but I hope you’ll put a lot more time into proof reading your new book. Mistakes like this happen often here and tell an entirely different story than the one you wish to put across.

    • October 12, 2015 at 3:37 pm

      Things have been very hectic these past few weeks…with the university back in session, the KS campaign, and a couple of projects with hard deadlines. I have already secured the services of a very experienced proof reader for the book.

  • October 12, 2015 at 4:38 am

    You list MQA under lossless compression, and this is indeed the marketing spin from Meridian. However, this distinction comes with a huge caveat. MQA can only be considered lossless up to 24kHz, and even then the term is used generously (the full 24-bit resolution is not preserved). Above 24kHz it applies lossy compression with more loss at higher frequencies. An accurate description would be “psychoacoustically transparent” since it’s unlikely that even the most golden of ears can detect any difference.

    • October 12, 2015 at 3:38 pm

      Thanks…I’m still waiting for Robert Stuart to come back to me with the answer I posed. I will follow up with additional details.

  • October 12, 2015 at 12:21 pm

    Except, maybe, OptimFROG, FLAC and MLP do not provide bit for bit accuracy.

    • October 12, 2015 at 3:39 pm

      Thanks Jay…others might reasonably disagree.


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