This list contains short definitions for common abbreviations in the field of digital audio recording. This material is taken from Recording magazine as well as other sources.
A/D (A to D) or, more correctly, ADC -- Analog to Digital Converter A device, either a stand-alone unit or a part of a digital audio processor, that converts analog signal (varying voltages) into digital data (ones and zeros). See also D/A. AES/EBU - Audio Engineering Society/European Broadcast Union A standard interface for digital audio transfer, using 3 pin microphone (XLR) connectors. Generally considered the "professional standard" if only for the type of cable and connectors used. Does not transfer SCMS data. Cable lengths for data transmission can be considerably longer than those for SPDIF transmission. AIFF - Audio Interchange File Format A format (one of many) for storing digital audio in a computer file, most commonly used on the Macintosh. Compare to WAV. ASCII - American Standard Code for Information Interchange The standard set of 7-bit codes to represent the keys on a computer keyboard. Also used to refer to generic text data with program-specific formatting. Example: "I can't read WordPerfect files. Please send me raw ASCII." ATRAC - Adaptive Transform Acoustic Coding A form of audio data compression used by the MiniDisc. ATRAC is "lossy," meaning that some data (judged to be unimportant to the ear) is discarded in the encoding process. ATRAC can compress data by about 5 to 1. See PASC. BNC A high-quality locking connector for 2-conductor low voltage electrical use. Most commonly used in video applications, also seen on mixing desks providing power to gooseneck lamps, and occasionally used elsewhere. On the Yamaha O2R BNC connectors are used for WORD SYNC to the TASCAM DA-88s. CPU - Central Processing Unit Although this term originally applied to the main microprocessor within a computer, today it usually refers to the box containing the computers "guts." The Intel 486 chip on the MicroSound's motherboard is a CPU. D/A (D to A) or, more correctly, DAC - Digital to Analog Converter A device that converts digital data into an analog signal. See A/D. DAE - Digidesign Audio Engine A Macintosh application that can run behind other applications (like digital audio sequencers or Pro Tools) and handle the nuts and bolts of getting audio data on and off the hard disk. By licensing DAE from Digidesign, sequencer developers avoid having to write their own low-level code to support digital audio operations. DAW - Digital Audio Workstation A computer, or more rarely a stand-alone console, with A/D and D/A converters, a large hard disk drive, and software tools for recording, editing, mixing, processing and playing back digital audio. DCC - Digital Compact Cassette A new format for digital audio recording and playback developed by Phillips, using digital tape and a stationary head. DCCs are similar in size and shape to standard analog cassettes, and DCC players can play back both types. Like MD, DCC uses data compression to fit more audio into less storage space. DSP - Digital Signal Processing The process of modifying audio in the digital domain; more specifically used to refer to software-based audio processing with a DAW, or to the computer chips designed to perform such operations. Every digital effects processor performs DSP. FPS - Frames per second There are several different frame rates and formats for SMPTE sync; the master and slave must be running at the same number of fps in order to sync properly. Commonly used from rates include 24 fps (used in film), 29.97 fps, and 30 fps (both used in video). IDE - Integrated Disk Electronics A standard interface bus in PC-compatible computers, used with many common components such as hard disks. MD - MiniDisc A new format for digital recording and playback developed by Sony, using a magnetic head and a low-powered laser. Like DCC, MD uses data compression to fit more audio into less storage space. MDM - Modular Digital Multitrack Generic term for any multitrack digital recorder using tape cartridges as a medium. The two most common formats are those used by the Alesis ADAT, using S-VHS tapes, and by the TASCAM DA-88, which uses Hi8 (8mm) tapes. MIDI - Musical Instrument Digital Interface Interface protocol originally developed for synthesizers but adapted to many other forms of audio gear. MIDI is a unidirectional serial spec running at 31.25KHz. MMC - MIDI Machine Control Part of the MIDI specification designed to control mechanical devices such as tape transports and lighting systems.i MTC - MIDI Time Code SMPTE time code is converted and broadcast over MIDI lines, allowing MIDI-savvy devices to sync to SMPTE time code. NTSC - National Television Standards Council Usually refers to the format of videotapes used in the USA and Japan. There are other, markedly different video standards used in other countries, such as PAL and SECAM. PASC - Precision Adaptive Subcoding A form of audio data compression used by the CDD. PASC, like ATRAC is a "lossy" compression method, and can compress data by about 4 to 1. PCI - Peripheral Component Interface An internal bus architecture for PC-compatible computers, now entering use in the Macintosh world as well. Digital audio cards are now being manufactured in PCI form. PCM - Pulse Code Modulation Used to refer to digitally-encoded audio data. Before the advent of DAT, PCM encoders like the Sony PCM-F1 were used to record digital audio onto conventional VCRs as a video signal, and to play it back with CD quality. RAM - Random Access Memory Memory that can be written to by the user, and overwritten as necessary. ROM - Read-Only Memory Memory that cannot be rewritten by the user. One type of ROM is EPROM, Erasable Programmable ROM, which can be rewritten, but only with special equipment. It is used for storing code that only needs to be updated rarely, such as operating systems. RT60 - Reverb Time to -60dB The time that it takes for reflections to decay to 60dB below the original signal strength, measured in seconds. Useful in describing not only the characteristics off acoustic treatments but also the parameters of digital reverbs. SCMS - Serial Copy Management System A special code included in digital audio data transmitted over S/PDIF that determines if copies of the data can be made. Originally intended to prevent piracy of digital recordings, SCMS is a nuisance to most audio professionals and is bypassed whenever possible, often by using AES/EBU transfers. SCSI - Small Computer Systems Interface A high-speed interface protocol originally developed for the Macintosh and adapted to many other platforms. SCSI is a useful interface for transferring large amounts of audio data in a hurry, and is used for backing up digital audio recorders and samplers. SMPTE - Society of Motion Picture and Television Engineers Used to refer to any of several types of sync signals used in the pro audio and video industries. SMPTE time code provides not only a steady relative sync but also contains precise absolute-time information, allowing a SMPTE slave device to chase and lock to a SMPTE master. S/PDIF - Sony/Phillips Digital Interface Format A protocol for transferring digital audio over 75-ohm video cable, S/PDIF uses standard RCA phono jacks and plugs. It's the digital interface favored on portable and consumer-grade DAT machines, due to its small, inexpensive connectors and the availability of SCMS. TDIF - TASCAM Digital Interface Format 8-channel digital interface used to connect TASCAM MDMs to one another and to other units. TDM - Time Division Multiplexing Digidesign's proprietary 24-bit DSP environment, providing real-time digital audio processing and mixing on Pro Tools hardware. Many third-party manufacturers make small programs designed to add special functions to TDM based systems; these are known as "plug-ins." The term itself refers to the "slicing" of each sample period into 256 different addresses, each available to a plug-in. WAV - Digital Audio File Format A format for storing digital audio data on a computer. WAV files are the preferred format for PC compatible computers. Compare to AIFF.