Glossary of Technical Terms and Abbreviations
Term |
Description |
| 1kHz, 1000Hz or 1 kilohertz
|
Tone of 1kHz is often used for line-up and testing. |
| AAC | Advanced Audio Coding - A widely used audio compression format designed to deliver high-quality sound at lower bitrates. It's a standard in digital audio and streaming, offering superior efficiency compared to older formats like MP3. |
| AES | Audio Engineering Society. AES sets professional audio standards, including AES3, which defines the digital audio interface for high-quality, balanced audio transmission in professional environments. |
| AES/EBU | Professional digital audio standard covering frame format, connections and interfaces. Interface is usually on XLR sockets and plugs. |
| AM | Amplitude Modulation - older analogue modulation standard used on long, medium and short wave. |
| AoIP | Audio over IP - A method of transmitting high-quality digital audio over standard IP networks. Widely adopted in professional audio and broadcasting, AoIP enables flexible, scalable, and cost-effective audio distribution, with protocols like Dante, Ravenna, and AES67 leading the way. |
| APT-X | Data reduction process for reducing the amount of storage or bit-rate need for audio. |
| Attenuation | The reduction of a signal level. Attenuation is usually measured in dB. |
| Bandwidth | The range of frequencies or data capacity available for transmitting audio, signals, or information in a network. In audio systems, bandwidth impacts sound quality and transmission efficiency, making it a critical factor in both analog and digital setups. |
| Balance | The relative levels of the left and right channels of a stereo signal. |
| Balanced Audio | A way of sending audio over cable that protects it from induced interference. |
| CAR | See racks room. |
| CAT 6 | Category 6 - An Ethernet cable capable of transmitting data at speeds up to 1 Gbps over 100 meters and 10 Gbps over shorter distances. CAT6 is ideal for high-performance networks, including those in professional audio setups and broadcasting environments. |
| Cart Machines | Descended from the hi-fi and in-car stereo 8 track players. Back in the "good old days" advertisements, jingles, news items (interviews etc.), station announcements or even music programmes were played on cart machines - recorders and players which used short looped tape (NAB cartridges or carts) and were able to fast-forward automatically at the end to the beginning of the material, ready for "almost instant" replay. Until 1996, Sonifex used to manufacture a number of machines, such as the micro HS and the CQ range. |
| Cart Splice-Finder/Eraser(s) | The splice on a NAB cartridge was where the tape looped and where the machine would cue to. A splice finder/eraser would erase the tape up to the cur-point. A bulk-eraser erases the tapes magnetically without splice-finding but operates faster and can handle more volume. |
| Cloud Audio Storage | A digital solution for storing, accessing, and distributing audio files over the internet. It enables seamless collaboration, sharing, and remote access, making it ideal for modern broadcasting and production workflows. |
| Cleanfeed | A cleanfeed is a signal produced by a telco module on a mixer which is used as the output to be fed back to a caller on a telephone line. The cleanfeed is a sum of all the other signals which constitute the programme output, except for the caller’s audio. A cleanfeed signal will generally be of a better quality than a mix-minus signal. |
| Clipping | The onset of severe distortion in the signal path, usually caused by the peak signal voltage being limited. |
| CMRR | Common Mode Rejection Ratio. This is the ratio of the extent to which a differential amplifier will cancel noise, which is present on both inputs, compared to its ability to amplify the signal. |
| CODEC | COder-DECoder - used to change a signal from one format to anther and back again. |
| Codecs | Using digital circuits being offered by telecom providers, usually ISDN (Integrated Services Data Networks) or other data transfer methods, audio can be transferred with good to excellent quality over what almost amount to dial-up telephone lines. The units operate by Coding the audio into a digital data stream that can be transferred over the digital circuit which is Decoded at the receiving end (Thus CoDec). By using single or multiple circuits, very high quality audio can be transferred from one place to another, even internationally. |
| Cross-talk | This is the amount of a signal from a bus which appears, or is induced, on a different signal. The problem is usually most prevalent with adjacent channels. |
| DA | Distribution Amplifier. |
| DAB | Digital Audio Broadcasting = now called Digital Radio. |
| Dante | Dante (Digital Audio Network Through Ethernet): A leading AoIP protocol by Audinate, enabling low-latency, high-quality digital audio transmission over standard Ethernet networks, widely used in professional audio systems. |
| dB ( decibel ) | A ratio of two voltages or signal levels, expressed by the equation dB=20LOG(V1/V2) Adding the suffix "u" denotes that the signal is relative to 0.775V RMS. Adding the suffix "v" denotes that the signal is relative to 1V RMS. |
| DCF | This is radio code signal sourced from Mainflingen, near Frankfurt in Germany, which can be used to automatically synchronize clocks and to an accurate atomic clock, European Time. |
| Digital Archive | A secure and scalable storage solution for preserving audio recordings, broadcasts, and metadata in a digital format. Digital archives ensure long-term accessibility and protection against data loss. |
| DI | Direct Inject - a means of diriving audio, usually from an instrument such as a guitar, to allow the audio signal to be fed directly into a sound desk input. |
| DLS | Dynamic Label segment - a text message scheme used in digital radio, usually to carry information about the programme. Like the radio-text scheme used in RDS. |
| DSP | Digital Signal Processing. |
| EBU | European Broadcasting Union. |
| EIN | Equivalent input noise. It is the ratio of output noise to the gain. It describes the level of noise which would need to be fed into an ideal amplifier to produce the measured output noise. |
| ENG | (Electronic news gathering). Machines that can record audio and video information digitally. |
| Edge Computing | A distributed computing paradigm that brings data processing and storage closer to the source of data generation. In broadcasting, it enhances efficiency by reducing latency and bandwidth requirements, enabling real-time processing for audio, video, and metadata. |
| EQ | (Equalisation). This is a method of cutting or boosting selected bands of frequencies in a signal. |
| FM | Frequency Modulation - a way of sending audio or data over a radio carrier, the 88 - 108 Broadcast Band is often known as the FM Band. |
| Frequency Response | The measure of a systems ability to reproduce audio across a range of frequencies, typically expressed as a graph showing the amplitude at different frequencies. Its crucial in evaluating the quality of microphones, speakers, and other audio equipment. |
| Gain | The degree of amplification, or attenuation, applied to a signal. |
| GRAM | Gramophone Reproducer - a turntable with a 'pick-up' amplifier and remote start interface. |
| HDLC | High Speed Data Link. |
| Hybrid | See T.B.U. |
| IEC | International Elecrotechnical Commision - often used to refer to a mains onnectivity standard, i.e. A type of plug/socket similar to that of a kettle, used on most pro-audio equipment. |
| IP Telephony | A technology that uses Internet Protocol (IP) networks to transmit voice, video, and data communications, replacing traditional phone systems like ISDN. It offers flexibility, scalability, and cost efficiency, making it a standard in modern telecommunications. |
| IGMP | Internet Group Management Protocol - A communication protocol used in IP networks to manage multicast group memberships. It allows devices like routers and hosts to coordinate and optimize the delivery of multicast data streams to multiple recipients. |
| kHz | Kilo Hertz (samples per second). |
| LAN | Local Area Network - scheme where several computers on the same premises are connected together so that they can exchange data. |
| LCD | A versatile display technology used in monitors, televisions, mobile devices, and audio equipment. LCDs offer bright, clear visuals and are widely adopted for their energy efficiency and adaptability across various industries. |
| LED | Energy-efficient lighting technology widely used in various applications, including bright and clear ON AIR signs, and audio-visual equipment. LEDs offer durability, low power consumption, and vibrant illumination. |
| LNB | Low Noise Block - the RF amplifier attached to a satellite dish. |
| Logging Recorders, Audio Loggers | It is a statutory requirement in many countries for radio stations to record their station output for a certain duration (in the UK it is 6 weeks). A logging system is used to record one, or a number, of audio channels, which is time-coded. The Flashlog and Net-Log range are examples of high quality audio loggers. |
| MCR | See racks room. |
| MDU | Mains Distribution Unit - a panel of mains outlets for power distribution. |
| MF | Medium Frequency - another name for Medium Wave - roughly frequencies between 300kHz and 3MHz. |
| MHz | Mega-hertz - One million cycles per second. |
| Mix-minus | A mix-minus is similar to a cleanfeed except that the caller’s voice is removed from the signal electronically. Due to phasing problems at the signal band edges, the mix-minus method often produces a lower grade signal. |
| Mono | Monophonic sound (system of broadcasting, recording or reproducing sound) using only one channel between source and loudspeaker. |
| MP3 | MPEG 1 Layer 3 - see MPEG. |
| MPEG (ISO MPEG) | Motion Picture Experts Group. For audio, this is used to refer to a framing format standard. There are several layers and variants. Most common ones are listed below. |
| MPEG 1 Layer 1 | Used for Digital Compact Cassette. |
| MPEG 1 Layer 2 | (Musicam) used in digital radio, digital terrestrial television, ISDN and many hard-disk storage systems. |
| MPEG 1 Layer 3 | Known as MP3. A more elaborate version of MPEG 1 Layer 2 that allows for audio stoarge using low bit-rates. |
| MSF | This is radio code signal sourced from Rugby in England, which can be used to automatically synchronize the clocks to an accurate atomic clock, UK Time. |
| Musicam | Masking Pattern Universal Sub-Band Encoding. |
| MUX | Short for Multiplex - a 'package' of digital radio services |
| News Editing | News-type editing typically consists of slicing through the gaps in conversation to remove the unwanted bits of an interview and preserve the 'sound bite' that illustrates, amplifies or supports the reported item. This does not require 'microscopic' accuracy - unlike music editing. Thus reasonably fast PC computers have sufficient ability to edit the compressed audio held on hard disc. |
| Non-Destructive Editing | Pointers are used to mark the start and end of points wanted phrases in the audio and the computer 'skips' the in-between bits! This is non-destructive and means many different versions of one interview can be produced - a short snippet for the news bulletin, a more in-depth extract for the local 'magazine' programme. Courier offers non-destructive editing, but can also create a new audio file from the edited piece. |
| Pan | This controls the levels sent to the left and right outputs and is an abbreviation of 'panorama'. |
| PFL | (Pre Fade Listen, or Cue). This is a method of auditioning audio material independently of the programme output, without routing the signal to air. The PFL button on each channel routes the signal to the PFL bus, where it can be monitored. |
| PoE | Power over Ethernet - Technology that delivers power and data to devices over a single Ethernet cable, simplifying setups and reducing the need for separate power sources. |
| PoE+ | Power over Ethernet Plus - An enhanced version of PoE, offering higher power delivery for demanding devices like PTZ cameras and larger network equipment. |
| PPM | Peak Performance Meter (BBC Specification). |
| Promo | Something used to promote a product. |
| Protocol | Refers to the rules and standards that enable communication between devices in a network. In professional audio, protocols like Dante, Ravenna, and AES67 ensure seamless audio transmission and interoperability across systems. |
| PSU | Power Supply Unit. |
| PTY (RDS and DAB) | Programme Type. A code transmitted to describe the overall programme content of a radio station (Static PTY) and/or the moment by moment content (Dynamic PTY). RDS has 32 codes although 3 are used in special circumstances only. |
| Racks Room | Often called the Master Control Room (MCR) or Central Apparatus Room (CAR), the racks room is an engineering area containing studio routing to transmitter equipment. Outside sources, phone-in equipment, off-air and transmitter status monitoring and logging equipment (or the transmitter itself !) are stored here with limited access. |
| Ravenna | A high-performance AoIP protocol designed for professional audio and media networks. It provides flexible, low-latency transmission of audio and other media data over standard IP networks, making it ideal for studios and broadcasting environments. |
| Reverb | An echo (in very basic terms). |
| RF | Radio Frequency. |
| RJ-45 | A widely used connection standard for Ethernet networking and some professional audio equipment. Its modular design ensures reliable data and signal transmission, making it versatile for both IT and audio applications. |
| S/PDIF | Sony/Phillips Digital Interface. Domestic digital audio interface standard using phono connectors or optically using fibre-optic connectors. |
| SPL | Sound Pressure Level. |
| Stereo Imaging | The spatial representation of sound within a stereo field, enhancing the perception of direction and depth in audio playback. |
| T/B | Talk-back (and reverse talk-back). This is the ability for two or more studios to communicate with each other off-air. |
| TCP/IP | Transmission Control Protocol / Internet Protocol. Computer interconnection methodology used on the internet and LANs. |
| Telemetry | The process of remotely collecting and transmitting data for monitoring and analysis. In professional audio and broadcast systems, telemetry can track equipment performance, network health, and system diagnostics in real time, enhancing reliability and maintenance. |
| Telephone Balance Unit (TBU) or Hybrid | Telephone hybrids provide the interface between professional audio equipment and the public telephone network. They provide protection for your equipment and the public telephone lines, allowing for varying line signals and line conditions. Automatically cancelling out the unwanted signal they also facilitate two-way communication down a single telephone line. In most European countries, including the UK, the TBU must be approved for connection to telephone company lines. Sonifex TBU's carry British Telecom and pan European approval. |
| THD | The Total Harmonic Distortion is the percentage presence of signals outside the measured reference frequency. |
| Threshold Level | The point at which a signal exceeds a predetermined level, triggering an action such as compression, limiting, or gating in audio processing. |
| U | A height measurement for rack-mount equipment: 1U = 1.75 inches 2U = 3.5 inches 3U = 5.25 inches 4U = 7 inches |
| UPS | Uninterruptable Power Supply. A device which maintains power to equipment when the electricity supply fails. |
| VHF | Very High Frequency - frequencies between 30MHz and 300MHz. |
| VP | Vertical Polarisation i.e. of DAB radio transmission. |
| VSWR | Voltage Standing Wave Radio |
| VU | Voltage units |
| Wavelength | The distance between successive crests of a wave, determining the pitch in audio signals or frequency in electromagnetic waves. Essential in understanding sound propagation and radio transmission. |
| X21 | A data communications protocol used in sychronous connections. |
| XLR | Professional, robust lockable audio connector - sometimes known as a 'Cannon' after one of the earlier manufacturers. |
