Glossary

5.1

The “5” refers to the number of audio channels; “1” indicates one subwoofer channel. Surround systems come in 5.1, 7.1, and more audio channels, but typically, a single subwoofer is all that is necessary for recreational use.

AIFF

AIFF stands for Audio Interchange File Format. AIFF is an uncompressed audio format created by Apple (and therefore the default on many Apple devices).

Ambisonics

Ambisonics is a surround sound format that uses B-format to enable adaptable 3-D sound for a variety of speaker configurations. B-format is a speaker-independent representation of sound fields. Using this feature of ambisonics, the sound engineer can code using directional cues that will be decoded by a listener’s individual speaker, versus hardwiring in directional instructions for a set speaker configuration

ARC

ARC (Audio Return Channel) is a technology found in devices like TVs, soundbars, and receivers, that allows audio data to be delivered via HDMI cable (from a TV to a speaker or sound bar, for example). ARC has become especially useful to audiophiles because it does not compress or downmix 5.1 music.

Audio Codec

A digital container in which PCM audio is encoded (packed) and then decoded (un-packed) back into PCM.

Audio Coding Formats

Audio coding formats refer to the more specific types of audio storage within the compressed and uncompressed categories. Examples of audio coding formats include MP3, AAC, Vorbis, FLAC, and Opus.

Audio Encoding

Audio Encoding is the process of changing audio files from one format to another. Audio has two broad formats: compressed and uncompressed. Most often, encoding refers to going from an uncompressed to compressed format.

Compressed audio has two classifications: lossless and lossy. “Lossless” audio can be decoded back into the exact uncompressed audio you started with. “Lossy” audio involves some loss of information.

Binaural Audio

Binaural audio is a form of audio that records/plays back two channels arranged with the intent to relay a 3-D effect for the listener.

Bitrate

A file’s bitrate is the amount of data that has been transferred into audio. The higher the bitrate, the more data, and in general, the higher the quality.

Blu-Ray Disc

A high-definition video disc that supports up to 8 channels of lossless audio (DTS-HD, Dolby TrueHD) and two channels of lossless audio. Blu-Ray disc also supports Dolby Atmos metadata embedded in a TrueHD audio stream.

Dolby Atmos

Dolby Atmos is a proprietary object-based audio format and platform developed by Dolby Laboratories. Atmos refers to an expansive and connected network of systems such as mixing software, specifications for cinema speaker arrays, and immersive audio hardware for home listening.

Dolby Digital (AC-3)

A lossy codec typically found on DVD-Video discs that supports up to six channels (5.1) at 48khz/16-bit, 448 kbps. It’s part of the ATSC television system, meaning that all television broadcasts utilize AC-3 5.1 audio.

Dolby Digital Plus (E-AC-3)

An “extended” version of AC-3 that supports up to 8 channels (7.1) at 48khz/20-bit, 640 kbps.

Dolby TrueHD

A lossless codec typically found on Blu-Ray discs that supports up to 8 channels (7.1) at 96-khz/24-bit, 18 mbps.

DTS

A lossy codec typically found on DVD-Video discs that supports up to six channels (5.1) at 48khz/16-bit, 1.5 mbps.

DTS 96/24

An “extended” version of DTS that supports up to 6 channels (6.1) at 96khz/24-bit, 1.5 mbps.

DTS-CD

A standard audio compact disc that contains 6 discrete channels (5.1) encoded in lossy DTS at 44.1-khz/16-bit.

DTS-HD Master Audio

A lossless codec typically found on Blu-Ray discs that supports up to 8 channels (7.1) at 192-khz/24-bit, 24.5 mbps.

DVD-Audio

A standard DVD that utilizes a lossless compression format called MLP (Meridian Lossless Packing) to deliver up to 6 channels of lossless audio at 96-khz/24-bit or two channels of lossless audio at 192-khz/24-bit.

DVD-Video

A standard-definition video disc that supports up to 6 channels of lossy audio (DTS, AC-3) and two channels of lossless audio.

Dynamic Range Compression

A form of processing that intentionally diminishes the contrast between the loudest and quietest moments in a given audio recording.

eARC

eArc (Enhanced Audio Return Channel) is a technology found in devices like TVs, soundbars, and receivers, that allows audio data to be delivered via HDMI cable (from a TV to a speaker or sound bar, for example). eARC has become especially useful to audiophiles because it transmits data for up to 32 channels.

FLAC (Free Lossless Audio Codec)

An open-source audio codec that utilizes lossless compression.

Headerless PCM

Standard file for converting analog audio into digital audio. It’s used for audio/visual data. PCM stands for Pulse-Code Modulation.

HRTF

HRTF stands for Head-Related Transfer Function. This term refers to the effect your head and ears have on the way you perceive sounds. Variation in a sound’s direction creates differences in phase and frequency which our brains recognize and use to locate the origin of the sound. Immersive audio can mirror the results of HRTF to give the perception that sound is coming from all around, even if it may be coming from a finite number of channels.

Lossless Compression

A method of compressing files that does not compromise their quality by allowing the compressed data to be reconstructed. Lossless compression allows files to take up less space and therefore are easier to download and store.

Lossy Compression

A method of compressing files that compromises their original quality. Lossy compression allows audio files to take up much less space at the cost of diminishing their sound quality.

MPC-HC

An open-source media player for Windows. It supports all common video and audio file formats available for playback and can be used to play Dolby Atmos MP4 files.

NFTs (Non-Fungible Tokens)

Data stored on a digital asset that denotes its unique value.

Object-Based Audio

Object-Based Audio is another approach to surround sound that breaks audio down into individual objects and uses meta-data to encode the connection between the objects, allowing for the audio to be played back accurately across a variety of systems.

Quadraphonic

Quadraphonic sound is a form of surround sound that uses 4 speakers – each in a different corner of the listening space – to play back independent signals creating an immersive effect for the listener.

Spatial Audio

Spatial audio is a classification of methods used to achieve surround sound. These methods include the binaural and object-based approaches to 360 degree audio.

Uncompressed audio

Audio files that have not been compressed by software. These files are typically large and can be difficult to download and store.

WAV

WAV is the industry standard for music production. Most engineers record into a WAV format to preserve sound quality. No compression takes place.