Technical information

Apollo Software Manual Glossary 195
Chapter 13: Glossary
A/D An acronym for “Analog to Digital,” which refers to the conversion of analog signals
to digital data.
Acronym A word formed from the first letters of other words (e.g., GUI, ADAT, TRS, etc.).
ADAT An acronym for “Alesis Digital Audio Tape.” ADAT was the name given to the
Alesis-branded products of the 1990s which recorded eight tracks of digital audio on a
standard S-VHS video cassette. The term now generally refers to the 8-channel optical
“Lightpipe” connection that is used in a wide range of digital products from many manu-
facturers.
AES (sometimes written as “AES/EBU“) The name of a digital audio transfer standard
jointly developed by the American-based Audio Engineering Society and the European
Broadcast Union. Designed to carry two channels of 16-, 20- or, 24-bit digital audio at
sampling rates of up to 192kHz, the most common AES physical interconnect utilizes a
3-conductor 110 ohm twisted pair cable, terminating at standard XLR connectors. (See
“Dual Wire” and “Single Wire”)
Analog Literally, an analog is a replica or representation of something. In audio signals,
changes in voltage are used to represent changes in acoustic sound pressure. Note that
analog audio is a continuous representation, as opposed to the quantized, or discrete
“stepped” representation created by digital devices. (See “Digital”)
API Acronym for Application Programming Interface. A software layer between an operat-
ing system and third-party hardware (such as an audio interface) and/or software (such
as a DAW). For example, a computer OS’s audio API enables audio hardware and audio
software from different vendors to communicate with the OS and each other.
Apollo Expanded Universal Audio’s name for connecting more than one Apollo device
together via Thunderbolt in a multi-unit cascading setup for increased I/O.
ASIO Acronym for Audio Stream Input/Output. ASIO is an audio interface driver protocol
for Windows operating systems developed by Steinberg GmbH.
Balanced Audio cabling that uses two twisted conductors enclosed in a single shield,
thus allowing relatively long cable runs with minimal signal loss and reduced induced
noise such as hum.
Bit A contraction of the words “binary” and “digit,” a bit is a number used in a digi-
tal system, and it can have only one of two values: 0 or 1. The number of bits in each
sample determines the theoretical maximum dynamic range of the audio data, regardless
of sample rate being used. Each additional bit adds approximately 6 dB to the dynamic
range of the audio. In addition, the use of more bits helps capture quieter signal more
accurately. (See “Sample” and “Dynamic range”)