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The Audio Engineers Dictionary A-E
| M | Electronics | Mu, letter of Greek alphabet used as SI prefix where it is pronounced as Micro meaning 1/100,000th (10^-6) |
| 3:1 Rule | microphones | Practical rule to avoid comb-filter distortion; keep adjacent microphones > three times as far apart as the distance between the sound source & the mic. |
| 3:2 Pull Down | Film | To transfer from 24fps (IE cinema Film) to 30fps each film frame is alternately scanned as 2, then 3 fields. The 30fps result comprises of 2 fields / Fm. Produces the correct running speed but often with motion artefacts |
| A/D | Digital | Analog to Digital converter |
| AAC | Digital | Advanced Audio Coding. Lossy data Reduction part of MPEG-2 & beyond. |
| Absorption | Loss or conversion of energy into a less useful form as it travels though a medium | |
| Academy frame {ratio} | Film | 1.33 aspect Ratio as used for presentation of all Silent & sound movies up to the 1950's. Also TV |
| Academy Roll off Curve | Film | Academy of Motion Picture Arts & Sciences Hiss/noise reducing HF filter, flat to 1kHz, 2K@-1, 5k@-4, 9k@-10, 10kHz@-12 |
| ACM | computer | Audio Compression Manager, part of MS (r) Windows where Audio CODECS are stored Eg to be able to play MP3 files |
| ACPI | Computer | Advanced Configuration & Power Interface, Gives power saving & IRQ steering Can cause problems on Pc's used for Audio |
| active circuit | Analog | electronic circuit containing Valves or transistors IE can have gain |
| Active Lines | Video | with a 625 line video picture only 576 lines contain picture info |
| ADPCM | Digital | Adaptive Differential {or Delta} Pulse Code Modulation. A/D conversion where the difference rather than the actual value is stored. Often used as a lossy data reduction scheme |
| ADR | Film | Automatic {or Assisted} Dialogue replacement. Re voicing due to technical or artistic fault(s) in the location recording aka Looping |
| ADSL | Digital | Asymmetrical Digital Subscriber Line; data via standard phone line, Asymmetrical = different data rates Up & down stream, IE up to 640kb/s send/ 8Mb/s receive |
| ADSR | Attack Decay Sustain Release. Typical 4 stages in an amplitude envelope. | |
| AES/EBU | Digital | Digital audio interface jointly conceived by the Audio Engineering Society and the European Broadcasting Union. Standard IEC-958. 2 Channels Max 24Bit, usually uses XLR (3 pin) See S/PDIF. |
| AES31-3 | Digital | File format & Edl spec for interchange between DAW's |
| Aftertouch | MIDI | Midi message sending data about overall pressure applied to the keys of a keyboard whilst notes are sustained. Also known as Channel Aftertouch. |
| AGP | Computer | Accelerated {Advanced} Graphics Port. Much improved over PCI buss port for graphics cards. Post 1997 |
| AIFF | Computer | Audio Interchange File Format. Digital Audio, native for Mac |
| aka | Also Known As | |
| Allpass filter | Phase shifter; Circuit that phase shifts on a frequency selective basis (as any other Filter) but gives no frequency dependant attenuation or boost | |
| Alpha | Graphics | As well as RGB or CMYK a amount of transparency or Alpha channel is supported Eg PSD & PNG formats |
| Alpha | Computer | a functional initial build of a program that probably has a number of bugs |
| Alpha numeric | Computer | The letters A-Z, numbers and generally other symbols on a typewriter style keyboard |
| AM | Electronics | Amplitude Modulation. A carrier wave is modulated in level |
| Ambience (Atmos) | Film | Low level sound effects that set a mood or suggest the character of a particular place. |
| ambisonics | Surround Sound | Method of recording (+ playback) a full perphonic soundfield as 4 components, W sound pressure and three pressure gradient (fig 8) signals XY&Z. see B format |
| Amp | Electronics | Ampere. Unit of electric current equals one coulomb per second. 1Amp will flow in a circuit with 1ohm resistance if 1Volt is applied |
| amp | Analog | Amplifier |
| amplifier | Electronics | An electronic circuit that increases signal level by increasing voltage or current. Amplifiers isolate one part of a circuit from another. Impedance matching amplifiers actually can decrease level. Preamplifiers are designed to handle small voltages, such as microphone signals. Power amplifiers are designed to drive loudspeakers. |
| amplitude | signal level. Often measured in dB above a reference point. | |
| Analog | (in UK Eng traditionally spelt analogue) one continually varying quantity {Eg sound/air pressure) is represented by a 2nd analogous one {Eg Volts} | |
| Analogue Synthesis | Or Subtractive Synthesis. Reproducing real organic sounds through the use and manipulation of simple electronic waveforms. Usually, the waveforms are harmonically rich and filters will remove unwanted content. | |
| Anamorphic | Film | Lens or optical attachment that squeezes {on a camera} or unsqueezes {movie projector} the width of the image used in CinemaScope & Panavision formats |
| Anechoic | Acoustics | a room with no reverberation, or total absorption of sound |
| ANSI | Computer | American National Standards Institute. They have set the standard for Screen display of text under DOS |
| Answer Print | Film | First print from a cut negative containing picture density & colour corrections probable also a combined optical sound track |
| API | Computer | Application Program Interface; set of commands to program a device or software (Eg Windows Media) |
| Application | Computer | An executable piece of code or program. Is specific to a particular operating system. On a PC will have .EXT or .COM extension On an Atari .PRG |
| Arpeggiator | Synths | Pattern that regularly plays through the notes of a chord, making arpeggios. Usually found on Monophonic synthesizers. |
| ASCII | Computer | American Standard Code for Information Interchange. Standard for using a 7bit word for 128 defined letters & control characters found on a computer keyboard. A .TXT file uses only ASCII characters. |
| ASCII encoding | Computer | A way of sending Binary data via an E-mail. Eg BinHex, MIME and UUENCODE |
| ASIO | Computer | Audio Streaming Input Output; driver protocol |
| Aspect Ratio | Film | Ratio of screen width to height, the height being 1. Eg Panavision/CinemaScope has a Ratio of 2.35:1 For simplicity expressed as just 2.35. |
| Aspect Ratio | TV | Rather than use a sensible system as with Films TV picture shape tends to be expressed as a ratio of any 2 arbitrary numbers Eg Film 1.33 is 4:3, 1.77 is 16:9 |
| ASPI | Computer | Advanced SCSI Programming Interface (r) Adaptec, unified drivers for SCSI cards |
| Assembly Language | Computer | Very low level programming language, that will be specific to the CPU used |
| ATA | Computer | AT Attachment; a hard disk for the IBM AT computer |
| ATAPI | Computer | AT Atachment Packet Interface; aka ATA 4 Disk interface |
| ATM | Digital | Asynchronous Transfer Mode; data transmitted in 53 Byte packets or cells. Suitable for TDM and packet switching. |
| Atmos | Film | Atmosphere. Low level sound effects that set a mood or suggest the character of a particular place. |
| ATR | Audio Tape Recorder | |
| Attack | Fx Units | Time taken for parameter to rise from 0 to peak level |
| attenuator | Electronics | device for reducing signal level. Can contain active circuitry or just resistors. |
| atto | SI Units | prefix Symbol a Eg attogram (ag) = 0.000000000000000001grams Or 10^-18 |
| auditory canal | The Ear | auditory meatus. Ear canal extending from the concha to the eardrum (tympanic membrane) |
| auditory system | The Ear | hearing system comprising of the outer ear (pinna, concha, auditory meatus, and tympanic membrane), the middle ear (ossicles: malleus, incus, stapes), the inner ear (cochlea), and the brain. |
| AutoConform | Video | Software that can read an EDL & control 2 or more Broadcast VTR's [or Audio tape recorders] to produce a high quality replica of an offline edit |
| AutoTune | Fx Units | Automatic pitch shifter introduced by Antares. Will pitch shift audio to the nearest note in the chosen scale, virtually in real-time. |
| Aux | Auxiliary sends Used to provide a feed to musicians or Fx units from each channel of a mixing console | |
| AVI | Computer | Audio Video Interleave, MS (c) RIFF format, originally part of the Video for Windows standard |
| Avid | Film | Trade name of the most widely known Microprocessor based non linear editing system (NLE) for pictures & sound |
| axial modes | Acoustics | frequency dependant resonance between wall surfaces |
| B format | Surround Sound | 4 channel system to capture a full perphonic soundfield as 4 components, W sound pressure and three pressure gradient (fig 8) signals XY&Z. |
| Baby Legs | Film | a short {approx 1 m max} camera tripod. Legs implies a separate Pan & tilt head will be added |
| BAFTA | Film | British Academy of Film and Television Arts. |
| Balance | To mix or control the relative level & Eq of a number of sound sources. If from a multitrack often called a mixdown | |
| Balanced Line | A twisted pair of cables neither of which is at 0 volts; there is a 1800 polarity difference between the 2. May have a 3rd screening wire at 0Vols / Earth or ground potential. Used for Analog parts of phone system & high quality Pro audio | |
| bandpass filter | BP; Passes frequencies in specified band & attenuates all others | |
| Bandwidth | Digital | Upper limit to the amount of data per second that can be handled. Eg kBytye/sec See Baud |
| Bandwidth | Analog | Upper & lower frequency limit a system can pass with 3dB or less attenuation. Eg 20Hz-20kHz |
| BASIC | Computer | Beginner's All purpose Symbolic Instruction Code; a high level programming language |
| basilar membrane | The Ear | part of the human hearing system, a membrane in the cochlea of the ear has sensory cells. |
| Bass Trap | Acoustics | LF absorber |
| Baud | Computer | A measurement of data rate. For practical purposes can be regarded as the same as Bits/Sec but strictly the number of transitions / sec. Pronounced Bode |
| BBS | Computer | bulletin-board service. |
| BCC | Computer | Blind Carbon Copy; E-mail function to send without the people listed in the To or CC field knowing who else is to get the message |
| BCD | Computer | Binary Coded Decimal. 4bit word used to represent the decimal numerals 0-9 (as binary 0000 to 1001) |
| BeOs | Computer | Os {Operating System} from Be Inc designed for Audio & Video Data (unfortunately now obsolete) |
| Beta | Computer | Software that is not sufficiently de-bugged to be releasable, but is good enough for Beta Testing |
| Bias | Electronics | As applied to magnetic recording a RF signal mixed with audio to overcome the Reluctance of the tape to be magnetized Help to linearize & reduce distortion |
| bi-directional | Polar pattern, more commonly known as Fig 8 or unhelpfully as Cosine | |
| Binary | Computer | Numbering system based on 2 values: 0 and 1. This system is the one used by Computer. |
| binary code | Computer | Binary code is string of data bits: code strings 7 bits long show the ASCII |
| binary file transfer | Computer | The transfer of a file containing 8-bit data, as opposed to 7-bit ASCII |
| Binary Files | Computer | Contains data other than ASCII text information |
| binaural | Having or involving the use of two ears. | |
| BinHex | Computer | Mac standard method to encode Binary file as though text, so for Eg it can be sent via E-mail. Has extension .HQX |
| BIOS | Computer | Basic Input Output System. Software held in ROM or RAM that monitors hardware devices, Eg Disks, cards VDU |
| Bit | Computer | Binary Digit. Can have one of 2 values. Eg on/off 0/1 True/False Hi/Low |
| BITC | Film | Burnt In Timecode; Timecode display superimposed over a video image for human rather than machine reading {In USA aka Window Dub} |
| bitmap | Computer | Binary representation of a picture using a grid of small blocks called Pixels. A single pixel is used for each colour and can depending on the number of bits/pixel record different brightness levels. Eg 1bit/Pixel for black/white, 8bit/Pixel for 256 different brightness of Red/Green/Blue etc |
| Black & Burst | Video | A master House Sync generator. Like a Composite video signal but the picture part is blank IE just Sync & colour burst info |
| Blumlein pair | microphones | stereo microphone arrangement consisting 2, Figure of 8 (bi-directional), coincident microphones at an angle of 90� to one another. Named after Alan Dower Blumlein it being one of many stereo recording methods he invented |
| BNC connector | Electronics | Bayonet Coaxial connector either 50 or 75ohm, widely used for pro video signals also digital audio & clocks |
| Board | {US Eng} same as UK Eng, Desk aka Mixing Console | |
| Boolean Logic | Computer | In Boolean Algebra operators such as AND, OR, NOR, NOT used to test the truth of a comparison |
| Boolean operator | Computer | Eg AND, OR, NOT. Used to define search criteria, when using Internet and other database searches. Eg Cat NOT big |
| boot | Computer | to start a computer & load the Operating system |
| Bridge Rectifier | Electronics | Uses 4 diodes to provide full wave {positive & negative 1/2 cycles} conversion of AC to pulsating DC |
| buffer amp | Analog | a small signal amplifier typically with a high I/p impedance, low O/p Z and unity gain (or a slight attenuation) |
| Bug | computer | an error (human) in a program |
| Burst Error | Digital | Data error effecting a number of contiguous bits, eg tape dropouts. |
| Byte | Computer | BY eighTE, a word of 8 Bits. |
| C/C | Film | Cutting Copy. The rushes edited to form the C/c or workprint. |
| Cache | Computer | Memory space on a computer, reserved for storing frequently used instructions, makes it go faster. This memory space is usually takes the form of dedicated circuitry (hardware cache), or part of RAM memory (software cache). |
| CAL | Computer | Computer Assisted Learning |
| Cannon connector | Electronics | a ITT(r) XLR or compatible latching low voltage connector. Can have 3-8 pins, 3 pin vers standard for balanced analog and stereo digital AES/EBU 4 pin for 12V DC power to portable pro equipment |
| Capacitor | Electronics | Component that can store an Electrostatic charge. Rather like a rechargeable battery but not so volumetrically efficient |
| cardioid | Microphones | heart-shaped polar pattern, -6db @90deg |
| CBR | Digital | Constant Bit Rate see VBR |
| CBT | Computer | Computer Based Training |
| CCD | Electronics | Charged Coupled Device; array of analog light sensitive areas on a chip used for image gathering. Eg digital camera /Scanner |
| CD-R | Computer | Compact Disc Recordable. Once only. |
| CD-ROM | Computer | Compact disk read-only memory. CD containing computer files |
| CD-ROM | Computer | 12 cm disk, 1 sided/1 Layer) 0.635 gig |
| CD-ROM | Computer | 8 cm disk, 1 sided/1 Layer) 0.180 gig |
| CD-RW | Computer | Compact Disc Re-Writable. |
| CDS | Film | Cinema Digital Sound; obsolete |
| CELP | Digital | Code Excited Linear Prediction; Audio lossy data reduction encoding very low bit rate & awful sound quality |
| centi | SI Units | prefix Symbol c Eg centigram (cg) = 0.01grams Or 10^-2 |
| CGA | Computer | Obsolete graphics standard for PC's 320x200 pixels & 4 colours |
| CGI | Film | Computer Generated Images |
| character | Computer | Alpha numeric or other symbol such as Alt, Space & Tab encoded into 1Byte |
| chip | Computer | Silicon Chip. An Integrated Circuit containing a number of electronic devices such as transistors & capacitors. |
| Chorus | Fx Units | Slightly detuned copies of the main sound. Causes a fattening of the sound when combined with the original. Popular on bass sounds. |
| Chroma | Video | Colour aspect of a video signal {from greek khr�ma} |
| Chrominance | Video | Colour aspect of a video signal {from greek khr�ma} |
| CinemaScope | Film | Widescreen film format (c) Twentieth Century Fox Originally had 2.55 aspect ratio & 4 tr mag sound Uses Anamorphic lenses |
| client | Computer | Program that requests services from another computer called a server. |
| clipping | Electronics | distortion of a waveform passing though a system that cannot handle the peak voltage required. If viewed on an oscilloscope peaks are clipped |
| Clone | Digital | a clone is a copy but unlike an analog copy where extra noise & distortion is guaranteed, a clone is regarded as being identical to the original |
| Cluster | Computer | a number of Computer networked together and acting like 1 larger computer |
| CMYK | Cyan Magenta Yellow blacK, the 4 ink colours used for full colour printing on paper. Aka Subtractive colours + black | |
| coaxial | on the same axis IE a centre point & concentric circle(s) round it Eg Coax cable as used for unbalanced signals | |
| COBOL | Computer | Common Business Orientated Language |
| cochlea | The Ear | inner ear. Sound analysing part of the auditory system connected to the brain via auditory nerves. |
| Cocktail Party Effect | Acoustics | The ability of the humans to hear a desired sound by use of our binaural auditory abilities to locate the sound source direction |
| CODEC | Digital | COder/DECoder Software to encode/decode probably using data reduction. for Audio & Video |
| coercivity | resistance of a magnetic material to changes in magnetization. High Coercivity material needs a V large Magnetic field to demagnetise it. | |
| coincident | Microphones | 2 or more mic capsules in the same place. |
| colouration | Unwanted frequency response or Eq changes. Is an analogy to light which appears coloured if there are not equal amounts of Red/Green&Blue. | |
| comb filter | Alteration of the frequency response of a system as a result of constructive and destructive summing of a signal and a delayed version of the signal. If plotted on a linear frequency scale, it look like the teeth of a comb. | |
| command-line interface | Computer | Text based method of issuing commands, like open a file. Initiated by typing near English like words using a keyboard. eg DOS, UNIX & SSL. |
| CompactFlash | Flash memory card (r) SanDisk | |
| Component video | Video | Unlike Composite systems Eg PAL & NTSC the chrominance and luminance information are kept separate |
| Composite print | Film | Type of film print shown in Cinemas that has both pictures & audio on the same piece of film aka Married print |
| Composite Video | Video | Analog signal combining video sync pulses + chrominance and luminance visual information. Eg PAL, SECAM & NTSC |
| Compressor | Unit that reduces dynamic range by attenuating loud signals. Helps to give more consistency (& apparent loudness) to a performance. | |
| Computer | Computer | An electronic device that uses coded instructions to manage information. |
| Concert Pitch | Acoustics | ISO standard, middle A =440Hz |
| concha | The Ear | resonant cavity of the outer ear between the pinna and the ear canal. |
| Condenser | Electronics | Obsolete name for a Capacitor. |
| Condenser microphone | Microphone | Mic in which the diaphragm is one plate of a capacitor. Changes in capacitance caused by air vibrations are converted to a voltage. Requires a buffer amp very close to Capsule also a DC polarising voltage. |
| conductor | Electronics | material that allows the easy passage of electrons Eg wire |
| cps | Computer | Characters per second. And Obs name {now Hz} for Cycles per second |
| CPU | Computer | Central Processing Unit. A microprocessor. |
| CRC | Computer | Cyclic Redundancy Check; error checking test when transferring data. A check sum is added to data sent & then the receiver applies the same check. If they don't match, the data can be requested again |
| critical distance | Acoustics | Distance from a sound source where direct & reverberant sound are the same level |
| CrO2 | Chromium Dioxide. A High coercivity tape formulation popular for Video tape use. | |
| crosstalk | Leakage {usually unwanted} of Acoustic or Electrical signal into a signal path | |
| cursor | Computer | An on screen bar which usually blinks, indicates where the next line of text etc will appear. |
| CV / gate | Control Voltage / gate. Old triggering method used with analogue synths before MIDI and digital equipment. A voltage is sent to trigger a note from the VCO, then gated to interrupt the note. | |
| D/A | Digital | Digital to Analog converter aka DAC |
| D1 | Video | Digital VTR format 1; Professional 19mm {3/4} cassette Component I/O |
| D2 | Video | Digital VTR format 2; Professional 19mm {3/4} cassette Composite I/O |
| D3 | Video | Digital VTR format 3; Professional 12.5mm {1/2} cassette Composite I/O |
| D5 | Video | Digital VTR format 5; Professional 12.5mm {1/2} cassette Component I/O |
| DAB | Digital | Digital Audio Broadcasting, digital radio |
| Dailies | Film | {US Eng} same as Uk Rushes |
| Daisy Chain | MIDI | Serial connection of MIDI devices. |
| Damping | Electronics | ability of a device to stop oscillating when the source of the oscillation stops. Unerdamped = ringing Overdamped = dead |
| DAO | Computer | Disk At Once; all data is written in one session. For a CD Audio disk to be a master to Red Book standards data must be written this way. See TAO |
| DAT | Digital | Digital Audio Tape (recorder). 0.15 wide tape in a cassette. 16Bit stereo. Was known as RDAT, R = rotating heads. There was an SDAT (stationary head) but it was never released. |
| Data | Digital | Digital Information stored and processed by a computer. |
| Data Byte | MIDI | Starts with a 0. Carries relevant Data for the type of message defined by Status Byte of 7 bits (128 possibilities). |
| Daughter Board | Computer | circuit board {probably small} that plugs into a larger circuit board. Eg sound cards can have a superior MIDI sound module or Dig I/o via a daughter board |
| DAW | Computer | Digital Audio Workstation. Usually a computer with dedicated hardware and software for editing and processing digital audio. |
| dBFS | Digital | Decibels below full scale. Sound level meters on Digital recorders are calibrated in dBFS, 0dBFS is the maximum level IE all bits have a value of 1. |
| DDS | Computer | Digital Data Storage. Aka Data Dat. Cassettes same size as DAT but is designed with better error correction 2g to20gig capacity |
| dead | Acoustics | a room with little reverberation IE near anechoic |
| Decay | Time taken for a parameter to fall from peak level to sustain level once attack time is over. | |
| Decca Tree | Microphone | 3 spaced Omnidirectional Mics in a T layout. Invented by Decca UK, recording engineers |
| deci | SI Units | prefix Symbol d Eg decigram (dg) = 0.1grams Or 10^-1 |
| decibel | Tenth of a Bel =dB. A Bel is the logarithmic ratio of two powers. Has been adapted to cover Voltage etc | |
| decoding | Film | Electronic process of recovering surround information from a 2 channel encoded mix. Eg Dolby Pro Logic |
| deka | SI Units | prefix Symbol da Eg dekagram (dag) = 10grams Or 10^1 |
| Delay | Time separation between two events. Eg the arrival of a direct sound & 1st & subsequent reflections. | |
| Delay Line | Fx Units | Electronic device {usually digital} that can store then forward the signal with a time interval set by a user |
| Device Driver | Computer | piece of software that tells an operating system how to communicate with a device such as a Sound card, printer or MIDI interface |
| diaphragm | A membrane that is freely moved by sound vibrations. Eg a mic/ the eardrum. Or if moved by electrical energy, moves air. Eg Loudspeaker. | |
| diffraction | scattering of sound. (See diffraction grating.) | |
| diffraction grating | Optics | Grid or grating that splits light into its spectral/frequency/colour components Eg the pits pattern on a CD give a Rainbow effect |
| diffraction grating | Acoustics | Grid or grating that splits sound into its spectral/frequency components. This scatters the sound in all directions giving a diffused field. Eg Quadratic Diffuser |
| diffuse field | Acoustics | A sound field composed of sound arriving from all directions. |
| DigiBeta | Video | Digital Betacam; (r) Sony. Professional Component 10 bit Digital VTR using 2:1 compression |
| Digital | Digital | An analog waveform is represented as a series of binary numbers |
| DIMM | Computer | Dual In line Memory Module |
| Dipole Speaker | Film | Fig 8 {sometimes omnidirectional} radiating LS used to create a diffused surround soundfield |
| Directory | Computer | MS DOS name, post Win95 now called a folder |
| disk drive | Computer | A physical data storage device Eg hard disk and floppy disk. |
| Distortion | Non linearity between an input & output signal as it passes though a system. | |
| Dither | Digital | Process that linearizes digital audio by adding a random noise signal at very low level. It allows one to resolve sounds quieter than the lowest quanization level. |
| DLT | Computer | High capacity, speed & cost tape based data storage |
| DMA | Computer | Direct Memory Access (or Address) |
| DNS | Computer | Domain Name System. Internet service to convert a domain name eg alchemea.com into a numeric IP address |
| Dolby A | Analog | Dolby noise reduction. 4 band Compander system for professional use. |
| Dolby AC-3 | Film | Multichannel Lossy data reduction coding. Used on Dolby Digital Film prints & DVD-V |
| Dolby Digital | Film | Multichannel digital format used for cinema prints, DVD-V & some HDTV. Uses Dolby's AC-3 lossy data reduction. |
| Dolby Pro Logic | Film | Surround sound decoder. Analog IC that recovers 4 channels of Dolby Matrix encoded information carried on a 2 channel recording. |
| Dolby SR | Analog | Spectral recording. Analogue Noise reduction. The best Dolby noise reduction system, used on SVA Film prints & 1/2 -2 analog tape. |
| Dolby SRD | Film | 35 mm release prints containing both an Dolby Stereo SR encoded analog track & a Dolby Digital (D) optical soundtrack. |
| DOS | Computer | Disk Operating System from IBM and Microsoft. A command-line operating system & by implication its 16bit Disk format. |
| Double head | Film | Projector with 1 head & roll of film for the pictures & another for sound |
| DPI | Computer | dots per inch a measurement of how many picture elements, (pixels) per inch. Eg to specify the resolution of printers. |
| Driver | Computer | small file containing instructions to control hardware such as a sound card, |
| DSD | Direct Stream Digital Used by Sony for SACD. Delta modulation IE V High sample rate low bit rate {1 or 8 bits} | |
| DSP | Digital | Digital Signal processor |
| DTS | Film | Digital Theater Systems; 5.1 or 6.1 Surround system, Audio is on CD-ROM, synched to picture by an optical timecode track |
| Dual Boot | Computer | Computer with the ability to boot from 1 of 2 operating systems installed |
| dummy head | Microphones | Binaural technique using 2 Omnidirectional Pressure mics placed where a humans eardrum would be, but on a mannequin head with pinna. |
| Duplex | Computer | Full duplex connection {via a NIC for example} allows data to be sent and received simultaneously whereas a half duplex link alternate between sending and receiving data. |
| DVD | Removable Optical digital storage medium. Officially the letters have no meaning, previously Digital Versatile Disk & prior to that Digital Video disk. Can store data on 1 or 2 layers and on both sides of disc, each layer gives about 4 gig | |
| DVD-1 | 8 cm disk, 1 sided/1 Layer) 1.36 gig | |
| DVD-10 | 12 cm disk, 2 sided/1 Layer) 8.74 gig | |
| DVD-14 | 12 cm disk, 2 sided/Mixed Layer) 12.32 gig | |
| DVD-18 | 12 cm disk, 2 sided/2 Layer) 15.90 gig | |
| DVD-2 | 8 cm disk, 1 sided/2 Layer) 2.47 gig | |
| DVD-3 | 8 cm disk, 2 sided/1 Layer) 2.72 gig | |
| DVD-4 | 8 cm disk, 2 sided/2 Layer) 4.95 gig | |
| DVD-5 | 12 cm disk, 1 sided/1 Layer 4.37 gig | |
| DVD-9 | 12 cm disk, 1 sided/2 Layer) 7.95 gig | |
| DVD-A | DVD-Audio Proposed replacement for CD's. Has up to 8 channel surround, high bit & sample rates + graphics & movies | |
| DVD-R 1.0 | DVD-Recordable WORM 12 cm disk, 1 sided/1 Layer) 3.68 gig | |
| DVD-R 2.0 | DVD-Recordable 12 cm disk, 1 sided/1 Layer) 4.37 gig; 8.75 gig for rare 2 sided discs | |
| DVD-RAM 1.0 | 12 cm disk, 1 sided/1 Layer) 2.4 gig; 4.8 gig for 2 sided | |
| DVD-RAM 2.0 | 12 cm disk, 1 sided/1 Layer) 4.37 gig; 8.75 gig for 2 sided | |
| DVD-RAM 2.0 3 | 8 cm disk, 1 sided/1 Layer) 1.36 gig; 2.47 gig for 2 sided | |
| DVD-ROM | Computer | |
| DVD-RW 2.0 | DVD-ReWritable 12 cm disk, 1 sided/1 Layer) 4.37 gig; 8.75 gig for rare 2 sided discs | |
| DVD-V | DVD-Video Most common form of DVD, Better than VHS picture + surround sound | |
| DVE | Video | Digital Video Effects |
| dynamic microphone | Microphones | Vibration of the diaphragm in a dynamic microphone causes an electrical conductor to move in a magnetic field, this creates an electrical signal by induction. |
| dynamic range | Analog | Ratio of the loudest sound a system can handle with acceptable distortion to either the quietest sound perceivable or the noise floor. Generally expressed in dB's. |
| dynamics unit | Fx Units | dynamic range controlling devices Eg Compressor, Expander & Gate |
| early reflections | acoustics | Discrete delayed versions of a sound arriving after the Direct sound but before the diffused reverberant ones. If delays are 50ms> an echo will be heard |
| EBCDIC | Computer | Extended Binary Coded Decimal Interchange Code, a standard 8-bit character code used in computing and data transmission. See BCD |
| echo | Computer | data sent from 1 device to another is returned to the source. Used for data integrity checking. |
| Edge numbers | Film | Alpha numeric code. Typically at 20 frame intervals on 16mm & 16 frame on 35mm Camera film. Placed at edge of film outside the picture area |
| EDL | Film | Edit Decision List A text file that is human & machine readable showing Timecode start & end points for each clip/segment used in an edited programme. |
| Eg | exempli gratia (Latin) for example | |
| electret microphone | Microphones | Condenser or capacitor microphone with the capsule permanently charged so no external polarizing voltage is needed. |
| Electron | Electronics | negatively charged particle circling the nucleus of an atom |
| Computer | electronic mail. Messages delivered over a network, including the Internet. | |
| Emphasis | Digital | to improve the signal-to-noise ratio of CDs or DAT a high frequency boost (called Emphasis) is applied on record & a corresponding high frequency rolloff (called De-emphasis) is applied on playback. A flag in the subcode section of the CD/DAT tells the player when to use de-emphasis. |
| emulation | Computer | Software used to translate instruction written for 1 type of CPU/operating system to run on another system. Eg SoftWindows allows Macs to run PC programs. |
| Encryption | Computer | altering data to make it unreadable unless you have the Key to decrypt it |
| ensemble | Group of musicians performing together | |
| Entropy coding | Digital | A/D encoding in which short words are substituted for the most often used data values & long words substituted for infrequently used values. Used in Lossless data reduction Eg Huffman Coding |
| Envelope | Synthesis | Name given to the linear stages of one parameter varying over time. Can be applied to any parameter Eg: volume envelope. See ADSR. |
| EOX | MIDI | End Of SyseX - message indicating the end of manufacturer specific transmission. |
| EPROM | Computer | Erasable Programmable Read Only Memory; Read only memory chip that retains its information until it is exposed to ultraviolet light though a small clear window. Often used to upgrade firmware |
| equalization | (EQ) The use of filters to alter the frequency response of a system | |
| error correction | Digital | The use of extra bits Eg parity bits to check the validity of the data being sent |
| Eustachian tube | The Ear | Tube between middle ear and the pharynx that serves to equalise air pressure on both sides of the eardrum |
| Even Harmonics | acoustics | Harmonic in a complex wave that has a 2:1 or other even ratio to the fundamental |
| exa | SI Units | prefix Symbol E Eg exagram (Eg) = 1000000000000000000grams Or 10^18 |
| Exciter | Fx Units | Fx Processor which creates & adds upper harmonics |
| Expander | Fx Units | Unit that increases dynamic range by attenuating quiet signals. Helps minimize background noise on a performance. |
| extended character set | Computer | Extension to the ASCII 128 character set. Unfortunatly the extensions tend to be operating system specific unlike ASCII. |