α-Ω 0-9 A

Dictionary of Audio Terminology - M

m (lower-case) - The symbol for milli-.

M (upper-case) - The symbol for mega-.

MAC Address (Medium Access Control Address) (Also called MAC Name) - The (usually) 48-bit hardware address number unique to each LAN NIC (put there by the manufacturer), which identifies every network node.

MADI (multichannel audio digital interface) - An AES recommended practice document Digital Audio Engineering - Serial Multichannel Audio Digital Interface (MADI) AES-10-1991 (ANSI S4.43-1991) specifying and controlling the requirements for digital interconnection between multitrack recorders and mixing consoles.

MaGIC (Media-accelerated Global Information Carrier) - An acronym trademark of Gibson Guitar Corporation for their digital transport protocol.

magnet - A body that produces a magnetic field external to itself. [IEEE]

magnetic field - The electric field surrounding any current-carrying conductor. [IEEE] A condition found in the region around a magnet or an electric current, characterized by the existence of a detectable magnetic force at every point in the region and by the existence of magnetic poles. [AHD]

magnetic flux density (Symbol B or B-field) - The amount of magnetic flux through a unit area taken perpendicular to the direction of the magnetic flux. Also called magnetic induction. [AHD]


magnetic pickup – A device that "picks up" sound and converts it into an electrical signal.

Magnetite - The mineral form of black iron oxide, Fe3O4, that often occurs with magnesium, zinc, and manganese and is an important ore of iron. [AHD]

magnetostriction (magneto + (con)striction) - Deformation of a ferromagnetic material subjected to a magnetic field. [AHD]

magnitude - (1) A number assigned to a quantity so that it may be compared with other quantities. (2) A property that can be quantitatively described, such as the volume of a sphere, the length of a vector, or the value of a voltage or current waveform. [AHD]

mainframe - (1) A large powerful computer, often serving many connected terminals and usually used by large complex organizations. (2) The central processing unit of a computer exclusive of peripheral and remote devices. [AHD]

mandolin - A small lute-like instrument with a typically pear-shaped body and a straight fretted neck, having usually four sets of paired strings tuned in unison or octaves. [AHD]

mandolin rail - A device installed within a piano used to create the classic ragtime honky-tonk sound popularized in player pianos and nickelodeons.

mantissa - The fractional part of a logarithm, e.g., in the logarithm 1.83885, the mantissa is 0.83885. (The integer part of a number is called the characteristic. In the example the characteristic is 1.) Floating-point arithmetic also calls this the significand.

Marconi, Guglielmo - (b. 1874-1937) Italian engineer and inventor who in 1901 transmitted long-wave radio signals across the Atlantic Ocean and opened the door to a rapidly developing wireless industry. [AHD]

Marshall, Steven Curtis - (b. 1948-2006) American inventor, musician, engineer and producer who founded Marshall Electronic and changed his last name from Marshall to St. Croix because he loved the islands.

Martenot - An early synthesizer from 1928.

Martin, Christian Frederick - (b. 1796-1893) German emigrant who founded the legendary Martin & Co. guitar company in 1833.

mask or masking - (aka auditory masking) The human hearing phenomenon where the response to one stimulus is reduced in the presence of another, i.e., two sounds arrive but only one sound is heard.

Massa, Frank - (b. 1906-1990) American engineer who is considered the father of modern electroacoustics for developing the fundamental technology that became the foundation for electroacoustics.

mastering - The final step in the recording process, completed before the replication or streaming process.

master mic - Term referring to the microphone input on an automatic mic mixer that is the last to detect audio. A last-on mic becomes a master mic only if left open long enough.

master port - Term referring to the audio input port that is the last to detect audio.

matrix-encoding - A technique of storing more than two audio channels on a two-channel medium or transmission format.

matrix-mixer - Similar to the matrix switcher (or router) below, but with additional signal processing features on all the inputs and outputs.


Maxfield, J. P. - American engineer who developed and was granted U.S. Patent #2,019, 616 for the first three-channel stereophonic system in 1935.

maximally flat magnitude response - A type of electronic filter characterized by having a maximally flat magnitude response, i.e., no amplitude ripple in the passband.

maximally flat phase response - A type of crossover utilizing low-pass filter design characterized by having a linear phase response (or maximally flat phase response), but also a monotonically decreasing passband amplitude response.

maximum-length sequences (MLS) - A time-domain-based analyzer using a mathematically designed test signal optimized for sound analysis. The test signal (a maximum-length sequence) is electronically generated and characterized by having a flat energy-vs.-frequency curve over a wide frequency range.

Maxwell's equations - Four differential equations relating electricity and magnetism that form the basis of electrical and electronic engineering.

MAU (multistation access unit) - The MAU forms a ring of the devices and performs the back-up function of restoring the ring should one of the devices crash or lose its cable connection.

Mbps (million bits per second) - (always lower-case b) A popular measure of transmission speed, but should be Mibps, or mebi bits per second.

MBps (million bytes per second) - (always upper-case B) A popular measure of transmission speed, but should be MiBps, or mebi bytes per second.

MCA-I - Media Communications Association - International

McIntosh, Frank - (b. 1906-1990) American engineer and founder of McIntosh Labs.

MD (MiniDisc) - Trademark term for the Sony digital audio recordable optical storage system utilizing data compression to reduce disc size.

MDCT (modified discrete cosine transform) - A popular audio coding technology.

MDM (modular digital multitrack) - Generic term used to describe any of the families of digital audio multitrack recorders. The most common examples being the Alesis ADAT series and the Tascam DA-88 series.

MDS (multidimensional scaling) - A method of displaying differences between items.

mebi Symbol Mi - New term standardized by the IEC as Amendment 2 to IEC 60027-2 Letter Symbols to be Used in Electrical Technology to signify binary multiples of 1,048,576 (i.e., 220). Meant to distinguish between exact binary and decimal quantities, i.e., 1,048,576 verses 1,000,000. For example, it is now 16 mebibits, abbreviated 16 Mib, not 16 megabits or 16 Mb.

media converter or media manager - The ability to manage and the process of managing different media (coaxial cable, twisted-pair cable, and fiber-optics cable) used within the same network. Media management involves cable performance monitoring, cable break detection, planning for cable routes, as while as converting data signals between the various media.

medical conferencing - A specialized form of videoconferencing optimized for medical uses. It allows distance learning in medical education and delivers health care (including assisted medical operations) to patients and providers at a distance.

medium – (1) In reference to telecommunications, the transmission path along which a signal propagates, such as a twisted-pair, coaxial cable, waveguide, fiber optics, or through water, or air. (2) The material on which data are recorded, such as plain paper, paper tapes, punched cards, magnetic tapes, magnetic disks, or optical discs.

MEDUSA (Mob Excess Deterrent Using Silent Audio) - A microwave ray gun that beams sounds directly into people's brains, developed by Sierra Nevada Corporation. Short microwave bursts rapidly heat tissue, which causes a shockwave inside the skull that is detectable by the ears.

mega- (1) A prefix signifying one million (106). abbreviated M. (2) A prefix popularly used in computer work to signify multiples of 1,048,576 (i.e., 220), but should use mebi.

megabyte - Popular term meaning a million bytes but should be mebibytes.

Megacycle - Abbr. MHz One million cycles per second.

megahertz Abbr. MHz - One million cycles per second.

MEIEA (Music & Entertainment Industry Educators) - An international organization formed in 1979 to bring together educators with leaders of the music and entertainment industries.

Mel-filtered cepstral coefficients - An important analysis parameter in CBID systems. These coefficients describe the harmonic spectrum shape perceived by the human auditory system, i.e., they characterize the shape of sound.

melisma - A passage of several notes sung to one syllable of text, as in Gregorian chant. [AHD]

Mellotron - The first sampling keyboard, made famous by The Beatles, who used it prominently on their 1967 hit Strawberry Fields Forever. Not digital, it uses strips of magnetic recording tape.

memristor (memory resistor) - The theoretical fourth two-port passive-component element, with the other three being resistors, capacitors and inductors.

MEMS - microelectromechanical systems.

MEMS microphone - Pro audio theory and application for new microphones based on MEMS technology.

Mercer, Johnny - (b. 1909-1976) American songwriter who wrote the lyrics to more than a thousand songs and received nineteen Academy Award nominations.

Mesa filter - Term coined by Lake Technology Ltd for their Lake Contour™ EQ technology.

mesh ground (a.k.a. common-bonded network) "A system where every piece of structural and non-structural metalwork in a building is bonded together. This includes concrete reinforcing bars, girders, cable trays, ducts, deck-plates, gratings, frameworks, raised-floor stringers, conduits, elevators, window and door frames, and the metal pipe-work used for HVAC to make a highly interconnected system that is finally connected to the lightning protection system."

METAlliance (Music Engineering & Technology Alliance) - " ... collaborative community in which producers, engineers and audio technology manufacturers work together to ensure the highest standards of audio production and delivery through developing consumer formats." [From website.]

metadata - Data about data.

meter Abbr. m - (1) The international standard unit of length, approximately equivalent to 39.37 inches. It was redefined in 1983 as the distance traveled by light in a vacuum in 1/299,792,458 of a second. (2) In reference to indicators, any of various devices designed to measure time, distance, speed, or intensity or indicate and record or regulate the amount or volume, as of the flow of a gas or an electric current. (3) In reference to Music, (a) Division into measures or bars. (b). A specific rhythm determined by the number of beats and the time value assigned to each note in a measure. [AHD]

meter ballistics - Term describing the response characteristics of a meter indicator.

metric - Of or relating to the meter or the metric system. [AHD]

metronome - A device used to mark time by means of regularly recurring ticks or flashes at adjustable intervals. [AHD]

MFCC (mel-filtered cepstral coefficients) - An important analysis parameter in CBID systems. These coefficients describe the harmonic spectrum shape perceived by the human auditory system, i.e., they characterize the shape of sound.

MFLOPS (pronounced "mega-flops") (million floating point operations per second) - A measure of computing power.

mi - The third tone of the diatonic scale in solfeggio. [AHD]

MI (musical instrument) - A broad term used to describe the musical instrument marketplace in general.

MIAC (Music Industries Association of Canada) - "A national not-for-profit trade association that represents Canadian manufacturers, distributors and retailers of musical instruments and accessories, keyboards, sound reinforcement products and published music."

mice music - "Scientists have known for decades that female lab mice or their pheromones cause male lab mice to make ultrasonic vocalizations. But a new paper from researchers at Washington University School of Medicine in St. Louis establishes for the first time that the utterances of the male mice are songs."

mic-level - Nominal signal coming directly from a microphone. Very low, in the microvolts, and requires a preamp with at least 60 dB gain before using with any line-level equipment.

mickey-mics - mmF (micro-micro-Farad) - Old term used before pico- became standard.

micro - Prefix for one millionth (10-6), abbreviated µ.

microbar - A unit of pressure equal to one millionth of a bar.

microfarad Abbr. µF or uF - A unit of capacitance equal to one millionth (10-6) of a farad.

micrometer Abbr. µm - A unit of length equal to one thousandth (10-3) of a millimeter or one millionth (10-6)of a meter.

micron - A deprecated unit of measure equal to a micrometer, one-millionth of a meter.

microphone Abbr. mic - An electroacoustic transducer used to convert the input acoustic energy into an electrical energy output.

microphone directivity - microphone polar patterns.

microphone, optical - Light from an LED is directed onto a reflective diaphragm via an fiber optic cable. The diaphragm reflects part of the light into a receiver fiber optic cable. If the diaphragm is moved by sound signals, the reflected light bean is deflected, with the result that more or less light is coupled into the receiver fiber optic cable. At the end of the receiver fiber optic cable, a photodiode converts the light intensity variations into electric signals.

microphone polar patterns (also called microphone directivity response)

• omnidirectional A response pattern that is as close to a perfect sphere as possible, i.e., it is not directional at all, or is a non-directional microphone.

• cardioid An on-axis response shaped like a cardioid with essentially no pickup to the rear.

• supercardioid cardioid-shaped response that includes small pickup directly to the rear.

• hypercardioid A cardioid-shaped response that includes greater rear pickup than the supercardioid design.

• subcardioid A cardioid-shaped response that does not tuck-in or null at the rear, instead has a smooth flat response to the rear.

• figure-of-eight A bidirectional microphone or one that responds equally front and rear and not at all to side sounds.

• shotgun The most directional response pattern, characterized by small sensitivity lobes on the left, right, and rear, with extreme sensitivity to the front.

microphone sensitivity - The standard is to apply a 1 kHz sound source equal to 94 dB- SPL (one pascal) and then measure the output level and express it in mV/PA (millivolts per pascal). [IEC 60268-4]

microphonic - General reference, any noise cause by mechanical shock or vibration of elements in a system (IEEE Std 100). In reference to Audio, an electrical noise caused by mechanical or audio induced vibration of the object.

microprocessor - An integrated circuit that performs a variety of operations in accordance with a list of instructions.

microsecond Abbr. µs - One millionth (10-6) of a second.

Microsoft® (microcomputer software) - Founded by Bill Gates and Paul Allen in 1975, whose relationship began with their first business venture named Traf-O-Data.

microstrip - A flat transmission line consisting of a conductive strip and a ground plane separated by dielectric.

mic splitter - A phrase first coined by Franklin J. Miller, founder of Sescom, to describe a box fitted with female (inputs) and male (outputs) XLR mic connectors that allowed mic inputs to be routed to two, or more outputs. Usually passive, either hard-wired, or transformer connected.

middle C - The tone represented by a note on the first ledger line below a treble clef or the first ledger line above a bass clef. It is the first C below international pitch. [AHD] The pitch equals 261.6 Hz and is the MIDI note number 60.

MIDEM An exhibition for music professionals held in Cannes, France each year at the Palais des Festivals.

MIDI (musical instrument digital interface) - Industry standard bus and protocol for interconnection and control of musical instruments.

MIDI show control - A term originally created by Charlie Richmond (Richmond Sound Design) to describe a new form of MIDI control designed for live theater venues. His efforts resulted in the official MIDI Show Control (MSC) specification.

MIDI time code - Used to synchronize MIDI systems with the rest of the audio and video world.

military music - "Military justice is to justice what military music is to music." -- Groucho Marx [from Barber]

Miller effect - The input impedance, and hence frequency response, of an inverting voltage amplifier stage is strongly affected by the feedback from the output to the input. This effect was first described by John M. Miller in his paper, "Dependence of the input impedance of a three-electrode vacuum tube upon the load in the plate circuit," Scientific Papers of the Bureau of Standards Vol. 15, pp. 367-385, 1920.

milli - Prefix for one thousandth (10-3), abbreviated m.

milliampere Abbr. mA - A unit of current equal to one thousandth (10-3) of an ampere.

millihenry Abbr. mH - A unit of inductance equal to one thousandth (10-3) of a henry.

millimeter Abbr. mm - A unit of length equal to one thousandth (10-3) of a meter.

millisecond Abbr. ms - A unit of time equal to one thousandth (10-3) of a second.

millivolt Abbr. mV - A unit of voltage equal to one thousandth (10-3) of a volt.

MIM (Music Instrument Museum) - "With musical instruments from every country in the world, MIM will pay homage to the history and diversity of instruments and introduce museum guests to their varied and unique sounds. MIM will be an engaging, entertaining, and informative experience, in which the uninitiated and the knowledgeable, the young and the old will feel welcome." [from website]

MIMO (pronounced "my-moh" or "me-moh") (multiple-input multiple-output) - A broadcast technology utilizing multiple antennas at the transmitter and the receiver for better communication.

Minifon - An early portable dictating machine developed in the 1950s using wire recorder technology.

minimum-phase - "If a network is minimum phase, there exists a unique relationship between amplitude and phase which allows a complete determination of phase from amplitude." [Richard C. Heyser, "Loudspeaker Phase Characteristics and Time Delay Distortion: Part 1," J. Audio Eng. Soc., vol. 17, p. 31 (Jan., 1969).

minimum-phase filters - From an electrical engineering viewpoint, the precise definition of a minimum-phase function is a detailed mathematical concept involving positive real transfer functions, i.e., transfer functions with all zeros restricted to the left half s-plane (complex frequency plane using the Laplace transform operator s). This guarantees unconditional stability in the circuit. In reference to Acoustics, a term used to mean a linear phase (or phase linear, European term) system.

minimum-phase loudspeaker - One where "the measurement of either phase or amplitude is sufficient to characterized the frequency response completely." [Richard C. Heyser, "Loudspeaker Phase Characteristics and Time Delay Distortion: Part 1," J. Audio Eng. Soc., vol. 17, p. 31 (Jan., 1969).

minute (time) Abbr. min - A unit of time equal to one sixtieth of an hour, or 60 seconds.

minute (plane angle) Abbr. ' - A unit of angular measurement equal to one sixtieth of a degree, or 60 seconds.

MIPA (Musikmesse International Press Awards) More than 100 international pro audio magazines award the best of each year's Musikmesse trade show.

MIPS (million instructions processed per second) - A measure of computing power.

mix-minus - A specialized matrix-mixer where there is one output associated with each input that includes all other inputs except the one it is associated with. (The output is the complete mix, minus the one input.)

mixer - At its simplest level, an audio device used to add (combine or sum) multiple inputs into one or two outputs, complete with level controls on all inputs.

mLAN (music local area network) - A technology developed and licensed by Yamaha based on the IEEE 1394 standard. It is a high-level multichannel audio, video and MIDI networking and connection-management protocol.

MLP (Meridian Lossless Packing) - A lossless audio coding scheme developed by Meridian Audio Ltd.


MLSSA (pronounced "Melissa") (maximum-length sequences system analyzer) - Trademarked name for the first MLS measurement instrument designed by DRA Laboratories (Sarasota, FL). M.R. Schroeder used maximum-length-sequences methods for room impulse response measurement in 1979 (based on work dating back to the mid-60's); however, it was not until 1987 that the use of MLS became commercially available. The first MLS instrument was developed and made practical by Douglas Rife, who described the principles in his landmark paper (co-authored by John Vanderkooy, University of Waterloo) "Transfer-Function Measurement with Maximum-Length Sequences" (J. Audio Eng. Soc., vol. 37, no. 6, June 1989), and followed up with new applications described in "Modulation Transfer Function Measurement with Maximum-Length Sequences" (J. Audio Eng. Soc., vol. 40, no. 10, October 1992).

MMA (MIDI Manufacturers Association) - The original source for information on MIDI technology, where companies work together to create the standards upon which MIDI compatibility is built.


MMVF (multimedia video file) - (NEC's 5.2 Gbyte Multimedia Video File Disk system) Now officially shifted from a laboratory project to a business project.

MNEC (Mass Notification & Emergency Communications) - A trade organization providing resources for personnel working with the National Fire Alarm and Signaling Code (NFPA 72).

Möbius, August Ferdinand - (b. 1790-1868) German mathematician and astronomer famous for his "strip" and as a pioneer in the field of topology.

Möbius (or Moebius) strip - A topological oddity, it is a continuous closed surface with no outside and no inside, i.e., it is a one-sided two-dimensional surface.

MOBO (Music of Black Origin) - An organization that "identifies, showcases and celebrates music derived from black heritage." A U.K. award show called the MOBO Awards.

modal - In reference to Acoustics, of, relating to, or characteristic of a room mode or modes. [AHD]


modem (modulator-demodulator) - A peripheral device used to convert digital signals ("1s" and "0s") into analog signals (tones) and vice versa, necessary for communication using standard telephone lines.

modified discrete cosine transform - A popular audio coding technology.


modulation - (1) The act or process of modulating. (2) The state of being modulated. (3) In reference to music (a) A passing or transition from one key or tonality to another. (b) The result of such a transition. (4) (a) A change in stress, pitch, loudness, or tone of the voice; an inflection of the voice. (b) An instance of such a change or an inflection. (5) The harmonious use of language, as in poetry or prose. (6) In reference to electronics, the variation of a property of an electromagnetic wave or signal, such as its amplitude, frequency, or phase. [AHD]

modulation noise - Any artifact that did not exist in the original signal and that varies with the signal strength.

MOL (maximum output level) - The maximum output level of a magnetic tape is defined as the magnetization level at which a recorded 1 kHz sine wave reaches 3% third-harmonic distortion (note that is 3% THIRD-harmonic distortion -- not 3% TOTAL harmonic distortion). Also referred to as 3% distortion of the musical twelfth.

monaural - Relating to a system of transmitting, recording, or reproducing sound in which one or more sources are connected to a single channel. [AHD]

Monitor World - Area of the live sound stage where the monitor engineer mixes his/her magic and attempts to decipher cryptic hand signals from the performers.

monitor mixer - A mixer used to create the proper signals to drive the individual musician stage loudspeaker monitors.

mono - Shorten form of monophonic, or monaural, relating to a system of transmitting, recording, or reproducing sound in which one or more sources are connected to a single channel; monaural. [AHD] Compare to stereo.


monopole woofer system - Literally "one pole," the most common form of woofer system that acts like an omnidirectional sound source, thus exciting room modes more than the alternative dipole woofer systems.


Monte Carlo method - Of or relating to a problem-solving technique that uses random samples and other statistical methods for finding solutions to mathematical or physical problems. [AHD]

Moog, Robert A. - (b. 1934-2005) American engineer best known for inventing the Moog synthesizer.

Moog synthesizer - The first electronic keyboard invented by US engineer Robert A. Moog in collaboration with composer Herbert A. Deutsch.

moon guitar (yue qin) - Chinese lute "moon guitar" (for its round shape) with a circular body and four strings.

Moore's Law - (1) Named by the physicist Carver Mead, after Gordon E. Moore, a cofounder of Intel, who wrote in an Electronics magazine article in 1965, that computer chip complexity would double every twelve months for the next ten years. Ten years later his forecast proved to be correct. At that time, he then predicted that the doubling would happen every two years for the next ten years. Ten years later, he was, once again, proved correct. By combining the two predictions, Moore's Law is often stated as a doubling every 18 months. (2) The dictum that requires you to buy a new computer every two years.

MOR (magneto-optical recording) - An erasable optical disc system using magnetic media and laser reading/writing.

morin khuur - Mongolian horse-headed violin.

morphing Shorten form of metamorphose - To transform (an image) by computer: cinematic special effects that morphed the villain into a snake. [AHD]

Morse, Samuel Finley Breese - (b. 1791-1872) American artist (true fact) and inventor best known as co-inventor of Morse code.

MOS-CQE (Mean Opinion Score; Conversational Quality, Estimated) - A measurement of voice quality in communication systems.

MOSFET (metal-oxide semiconductor field-effect transistor) – A Field Effect Transistor where the gate is insulated from the channel by a very thin (typically less than the wavelength of light) layer of glass (silicon dioxide) and the gate is either metal or doped silicon (polysilicon), hence the acronym metal-oxide semiconductor.

Mosquito™ Teenage Deterrent - A security device used in the U.K. that emits a high-pitched scream at a frequency audible only to young people (roughly below the age of 20). With an effective range of about 20 meters, its aim is to break up loitering youths by annoyance and is, needless to say, a very controversial device.

motional feedback (servo-loop; servo-locked loop; servo-mechanism) - A self-regulating feedback system or mechanism. Typically a feedback system consisting of a sensing element, an amplifier, and a (servo)motor, used in the automatic control of a mechanical device (such as a loudspeaker). In audio, usually the name applies to a class of electronic control circuits comprised of an amplifier and a feedback path from the output signal that is compared with a reference signal.

MOTS (modified or modifiable off-the-shelf ) - Government procurement term. Most often referencing software but general use is found.

MOV (metal oxide varistor) - Semiconductor devices designed to provide protection against voltage and current transients.

Movement Electronic Music Festival - Beginning in 2000, an electronic music festival said to be the largest in the US, held yearly in Detroit over Memorial Day weekend.

moving coil Abbr. MC - A type of electromagnetic transducer that operates by having a mechanical device move a coil of wire in a magnetic filed to convert the mechanical movement into an electrical current. Invented and patented by General Electric researchers Chester Rice and Edward Kellogg in 1924.

moving magnet Abbr. MM - A type of electromagnetic transducer that operates by having a mechanical device move a magnet in a coil of wire to convert the mechanical movement into an electrical current. Invented in 1957 by ELAC.

Mozart, Wolfgang Amadeus - (b.1756-1791) Austrian composer.

MP3 (MPEG-1, Layer 3) - A type of digital audio compression popularized for transmitting songs over the Internet. MP3 allows real-time audio streaming for Internet encoding and downloading. MP3 files are identified by the suffix ".MP3" Typically MP3 compresses CD-quality audio down to about one minute per 1MB file size.

MPEG (Moving Picture Experts Group) - A working group within SMPTE who set, among other things, specifications for compression schemes for audio and video transmission. A term commonly used to make reference to their image-compression scheme (MPEG-2) for full motion video.


MPEG-4 Structured Audio - This specifies a set of tools that allow powerful and flexible description of sound in a variety of ways, all based on what has become known as "structured audio," meaning transmitting sound by describing it rather than compressing it.

MPGA (Music Producers Guild of the Americas) - The original professional guild for music producers and audio recording engineers, however in 2000, the Recording Academy absorbed it and established the Producers & Engineers Wing.

MPX - Abbreviation for multiplex as found in FM analog stereo broadcasting.

MR (magnetoresistive) - A technology based on the effect where electrical resistance in a material changes when brought in contact with a magnetic field.

M/S or M-S (mid-side or mono-stereo) microphone technique - Invented by Alan Blumlein and awarded US Patent 429,054, "Improvements in and relating to Sound-Transmission, Sound-Recording and Sound Reproducing Systems, filed in February 1934. It was first commercialized in the mid '50s by the Danish radio engineer Holger Lauridsen (H. Lauridsen & F. Schlegel, "Stereophonie und richtungsdiffuse Klangwiedergabe," Gravesaner Blätter, 1956, Nr. V, August, S.28-50). It is a method for capturing stereophonic sound using two microphones. One microphone with a cardioid response (although any polar pattern will work) is aimed straight ahead toward the sound source (this is the mid or mono M part), and a second microphone with a figure-8 (or bipolar) response is placed so that the two lobes are directed toward the sides (this is the side or stereoS part). The two signals are then combined using an M-S matrix circuit that yields two signals: M+S and M-S.

MS-DOS® (Microsoft® disk operating system) - Microsoft's registered trademark for their PC operating system.

MSB (most significant bit) - The bit within a digital word that represents the biggest possible single-bit coded value.

MSM (mid-side-mid, also called Double MS) - An extension of the M-S microphone technique using two coincident M-S pairs sharing the same side-facing figure-of-eight microphone, one pairing for the Front L and R and the other pairing for the surrounds Ls and Rs (from Mike Skeet's article "MSM Mic Surround Technique," Audio Media, May 2003, pp. 58-59.

MSO (Music Store Owners) - Originally called iSMO (Independent Music Store Owners) this organization exists to serve as a link between dealers, manufacturers and the public.

MSPS (million samples per second or megasamples per second) - A measurement of data converter speed.

MTBF (mean time between failure) - A measure based on statistical experience of how reliable a hardware product or component is, expressing in thousands or tens of thousands of hours as the predicted average time between failures.

MTC (MIDI time code) - used to synchronize MIDI systems with the rest of the audio and video world.

MTTR (mean time to repair or mean time to recovery) - A measure of the maintainability of a piece of equipment. It is the average time required to fix any removable item in a product or system.

mu - In reference to vacuum tubes, symbol for the tube's amplification factor.

Mu Law - The PCM voice coding and companding standard used in Japan and North America. [Newton]


mult - Shortened form for "multiplex" or "multiple." Refers to routing or splitting signals to multiple destinations. Found on patchbays where several "mult" jacks make a signal available to many devices.

multicasting - Multicasting sends a message to a specified few.

multiclient ASIO driver - Refers to a software ASIO driver capable of interfacing external hardware devices with multiple software applications (clients) on a computer.

multicore - Two or more processors in a single package.

multi-denomial transpedance informer - Term coined by Jensen Transformers for their mythical product, the JE-EP-ERs, first introduced in 1987, which almost changed the whole audio transformer industry. The Jensen JE-EP-ERs pioneered the use of triple electonomic shielding and intrinsic eddy-breeding, until outlawed by Congress in 1988.

multidimensional scaling - A method of displaying differences between items.

multimedia - Generally refers to personal computers capable of multiple forms of communication methods. These constitute a minimum combination of stereo audio, video, text, and graphics, plus the more complex system includes fax and telephony provisions.


multipath - Short for "multipath interference" or "multipath distortion." Interference due to multiple arrivals of the same broadcast signal due to reflections off buildings (usually).

multiplex - To interleave two or more signals into a single output; a process of selecting one of a number of inputs and switching its information to the output.

multipoint conference - Telecommunication term referring to conferencing between three or more sites.

multitrack - The most popular method of music recording where each instrument, or group of instruments, is recorded on separate tracks (called stems) and then mixed down to a final version.

mu-metal - A nickel-iron alloy used primarily for magnetic shielding.

Munson, W. A. - American physicist who first measured the human ear's loudness response with Harvey Fletcher and known today as the Fletcher-Munson curves.

Murphy, Edsel and Murphy's Law - The dictum that if anything can go wrong, it will.

music - (1) The art of arranging sounds in time so as to produce a continuous, unified, and evocative composition, as through melody, harmony, rhythm, and timbre. [AHD] (2) The art or science of combining vocal or instrumental sounds with a view to beauty or coherence of form and expression of emotion. [OED] (3) The science of harmonical sounds.

Musical Telegraph - The first electronic synthesizer invented by Elisha Gray that created and transmitted sound over telegraph lines.

musical twelfth - The third-harmonic of a tone, which equals one octave and a fifth -- hence, twelfth (12 not 13 because you don't count the original tone).

MUSICAM (masking pattern adapted universal sub-band integrated coding and multiplexing) - A flexible bit rate reduction standard for high quality audio. Jointly developed for digital audio broadcast by CCETT in France, IRT in Germany and Philips in the Netherlands.

Music Genome Project© - A mathematical algorithm, granted US Patent Number 7003515, developed by its inventors to identify and describe music based on over 400 attributes. Using this algorithm it is possible to know a song's genre without listening to it.


músick - Defined by Samuel Johnson in his magnum opus, A Dictionary of the English Language, published in 1755, as "The science of harmonical sounds."

music note value - In music notation, a note value indicates the relative duration of a note, using the color or shape of the note head, the presence or absence of a stem, and the presence or absence of flags/beams/hooks/tails.

Music Rising - A charity created in 2005 by U2's lead guitarist, the Edge, music producer Bob Ezrin and Henry Juszkiewicz, Chairman and CEO of Gibson Guitar Corp., along with musical partner Guitar Center.

music temperament - The building up of musical scales.

music vs. noise - (1) "The sensation of a musical tone is due to a rapid periodic motion of the sonorous body; the sensation of a noise to non-periodic motion." from On the Sensation of Tone(1862) Hermann Helmholtz. (2) "Of all noises, I think music is the least disagreeable." -- Samuel Johnson [from Barber]

Musikmesse - The world's largest music trade show help annually in Frankfurt, Germany.

musique abstraite - Music written for later playing; normal music as opposed to musique concrète.

musique concrète - Electronic music composed of instrumental and natural sounds often altered or distorted in the recording process. [AHD]

Mutek - A Montreal music festival. "A not-for-profit organization dedicated to the dissemination and development of digital creativity in sound, music, and audio-visual art." [from website]

mutual coupling - General term describing the combining behavior of two or more drivers reproducing the same frequency. If two or more identical loudspeakers are mounted such that their acoustic centers are close together (i.e., some fraction of a wavelength), their acoustic outputs over some frequency range will combine (couple) and propagate forward as one waveform, thus two smaller drivers behave as one big driver.

mute - A control found on recording consoles, some mixers, and certain signal processing units that silences (mutes) a signal path, or output.

Muzak (music + Kodak) - Trademark of the business music company founded in 1928 by General George Owen Squier who patented the transmission of background music (phonograph records played through the telephone system).

MVCDL (multiple voice coil digital loudspeaker) - A type of direct digital loudspeaker.

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