Pro Audio Reference


Pro Audio Reference (L)


L The electronic symbol for an inductor.

la Music. The sixth tone of the diatonic scale in solfeggio. [AHD]

LAB (Live Audio Board) Topics related to sound reinforcement and application of audio for live events — the most active pro audio forum on the Web, created by road dog Dave Stevens and hosted by

lacquer crackers Records, platters, waxings, discs. [Decharne]

LAeq See equivalent continuous A-weighted sound pressure level.

Laff Box Invented by American sound engineer Charles Douglass (1910-2003) in 1953, it provided canned laughter for TV programs, including I Love Lucy.

lag Electronics. 1. The difference in phase between a current and the voltage that produced it, expressed in electrical degrees. 2. The delay in action of a sensing element of a control element. [ IEEE Std 241]

La MaMa An experimental theater club located in NY city, begun in 1961 by Ellen Stewart.

Lamarr, Hedy (1924-2000) Born Hedy Kiesler in Vienna, this Hollywood actress used her knowledge of musical harmony, along with composer George Antheil, to obtain a patent on technology for military communications in 1942, establishing the groundwork for today's spread-spectrum communication technology.

Lambeg drum Musical Instrument. Claimed to be one of the loudest (>120 dB) acoustic instruments in the world, it is a large Irish drum, beaten with curved rattan canes.

LAMC (Latin Alternative Music Conference) A yearly conference held in NY City, usually in July, featuring Latin alternative music.

LAN (local area network) A combination of at least two computers and peripherals on a common wiring scheme, which allows two-way communication of data between any devices on the network.

Laneway Festival See: St. Jerome's Laneway Festival.

Lansing Iconic Loudspeaker. The first recording studio monitor loudspeaker designed and manufactured by Lansing Manufacturing Company in 1927. Hit the link for pictures and details.

Laplace, Marquis Pierre Simon de (1749-1827) French mathematician and astronomer who formulated the theory of probability.

Laplace transform Electronic circuit analysis. A powerful circuit analysis technique that transforms difficult differential equations into simple algebra problems. Omitting all the mathematical details to get to the essence, the Laplace transform substitutes the Laplace operator "s" to represent complex frequency impedances. Therefore inductive reactance, XL is represented by "sL" and capacitive reactance, XC becomes 1/sC.

LARES (Lexicon Acoustic Reinforcement and Enhancement System) The time-varying reverberation system invented and developed by David Griesinger while at Lexicon beginning in 1991. Details here: Improving Room Acoustics through time-variant synthetic reverberation by David Griesinger. This is an example of an EAE system.

largo Music Terminology. Broad, slow. [Sadie]

Larsen Effect Acoustics. Name for acoustic feedback. (After Søren Larsen.)

Larsen, Søren Arsalon (1871-1957) Danish physicist notable for his contributions on acoustic feedback.

larynx See voice box.

laser (light amplification by stimulated emission of radiation) A device that generates coherent, monochromatic light waves. All CD players contain a semiconductor laser in their optical pickup.

laser microphone Microphones. An entirely new type of microphone invented by David Schwartz that promises conversion of acoustical to electrical energy with zero distortion.

laser turntable Phonographs. A phonograph that plays vinyl records using a laser instead of a cartridge so there is no contact between the record and the laser sensor. Beginning at $15,000, it is not cheap, but very innovative.

last-on Teleconferencing. Term referring to microphone inputs on an automatic mic mixer that stay on (open) until another mic input turns on. Contrast with gated-on. A last-on mic becomes a master mic if left open long enough.

Las Vegas City of Lights Jazz and R&B Festival A picnic-style (grass and lawn chairs) venue jazz festival held yearly in Las Vegas in the Spring.

LAT (linear array transducer) Loudspeakers. Trademarked name for a new loudspeaker technology developed by Tymphany Corporation. For details see AES preprints #6191, 6247 and 6250.

latency Similar to propagation delay but broader in application. Used to describe the inherent delay in signal processing as well as software processing. The time it takes for a system or device to respond to an instruction, or the time it takes for a signal to pass through a device. It is how long it takes for a result to happen from a command. In telecommunications it is the length of time it takes packets to traverse the media.

laugh box See Laff Box.

lavaliere or lavaliere microphone A small electret microphone designed to be worn on a person. The first lavaliere mics were worn around the neck on a lanyard, hence the French name lavallière, a type of necktie, used to describe a pendant worn on a chain around the neck (after the Duchess de La Vallière who started the fashion [AHD]). Today most lavaliere (the final "e" is commonly dropped) mics are attached by clips rather than hung from a cord.

lawful "Compatible with the will of a judge having jurisdiction." — Ambrose Bierce.

lawyer "One skilled in circumvention of the law." — Ambrose Bierce.

lay Wire & Cable. To place together (strands) to be twisted into rope. To make in this manner: lay up cable. [AHD] The number of twists per unit length in twisted cable, called the lay. The helical arrangement formed by twisting together the individual elements of a cable. [IEEE]

Layer 1 In the 7-layer OSI network model, this is the lowest level, and is known as the physical layer (seen abbreviated PHY) layer, characterized by the hardware of cables and connectors.

Layer 2 In the 7-layer OSI network model, this is the next to lowest level, known as the data link layer. This layer defines how date is transferred between network objects. In pro audio, the most common layer 2 uses Ethernet.

layback Recording. A post operation that rejoins audio and video after all other editing is complete.

LCD (liquid crystal display) A display of numerical or graphical information made of material whose reflectance or transmittance changes when an electric field is applied. An LCD requires ambient light or backlighting for viewing.

LCR (left center right) Sound Reinforcement. A three-channel sound system utilizing a left channel, a right channel and a center channel to stabilize the phantom images.

LDI (Live Design International) The largest US trade show and conference focused on technologies for the live entertainment industry.

LDR (light-detecting resistor or light-dependent resistor) An optoelectronic device whose resistance varies (inversely proportional) as a function of light ; a photocell, often constructed from CdS.

Leach Jr., William Marshall (1940-2010) American engineer and professor who made significant contributions to audio engineering throughout his life, including authoring 26 JAES papers.

lead-acid battery A storage battery in which the active material of the positive plate is lead dioxide, the negative plate is lead, and the electrolyte is dilute sulfuric acid. [ IEEE Std 1578]

leakage Microphones. Pickup of an instrument by a microphone intended to pick up another instrument. Creative leakage is artistically favorable leakage that adds a "loose" or "live" feel to a recording. [Vear]

Lear cartridge (aka 8-track cartridge) Recording. Invented by William Powell Lear, the man behind the LearJet; eventually superceded by the compact cassette.

LeBel, C. J. (1901-1960) American inventor and founder and first president of the Audio Engineering Society.

Leccese, Albert (1953-2010) American engineer who helped pioneer touring sound as Director of Engineering at Audio Analysts.

LED (light-emitting diode) Invented by Nick Holonyak, Jr. in 1962, a self-lighting semiconductor display of numerical or graphical information based on the light emitting characteristics of a solid-state device that emits incoherent (i.e., random direction) light when conducting a forward current. See LEVD.

LEDE (live end-dead end) Acoustics. Recording studio acoustic treatment developed by Chips Davis in the late '70s where a room is designed to have a live end, i.e., reverberant and a dead end (opposite) that is heavily damped. Hit the link for the original AES paper written by Chips Davis and Don Davis (no relation) in 1980.

LEED® (Leadership in Energy and Environmental Design) A registered trademark of USGBC (US Green Building Council) An environmental rating system for the building industry — a "benchmark for the design, construction, and operation of high performance green buildings." See RaneNote: LEED and the MA 4 Multichannel Amplifier.

Leet Internet-based written slang, e.g., "leet" is Internet slang for "elite," "L8tr" for "later," and "l00kin6" for "looking, etc. Used to encrypt text messages, but it is much more sophisticated than the elementary "B4" for "before." It is a complicated use of letters and numbers that look like letters, e.g., "m4d" for "mad."

legacy devices Something handed down from an ancestor, or a predecessor, or something from the past [AHD]. Used in the computer world to refer to yesterday's solutions, for example including an RS-232 port on a USB machine.

LEO (low earth orbit) Telephony. Term referring to communications satellites positioned 200-900 miles (320-1450 kilometers) high.

lepatata See: vuvuzela

Leq Symbol for equivalent continuous sound pressure level.

Leq(A) Symbol for equivalent continuous sound pressure level (A-weighted). Also seen as LAeq.

Leslie Loudspeaker. A special loudspeaker design made famous by its use with the Hammond B-3 organ, featured prominently in much of the 1960's and 1970's music (Procol Harum, et al.) characterized by a swirling pitch-shifting sound. Designed in the 1940s by Don Leslie, it uses a fixed loudspeaker and a rotating horn assembly to cause a doppler sound effect.

Les Paul See: Paul, Les

LEV Acoustics. Acronym for listener envelopment. [Morfey]

LEVD (light emitting vegetable diode) True story; kimchi, actually. Some other foods also do it.

leveler (also seen as leveller, which is incorrect) A dynamic processor that maintains (or "levels") the amount of one audio signal based upon the level of a second audio signal. Normally, the second signal is from an ambient noise sensing microphone. For example, a restaurant is a typical application where it is desired to maintain paging and background music a specified loudness above the ambient noise. The leveler monitors the background noise, dynamically increasing and decreasing the main audio signal as necessary to maintain a constant loudness differential between the two. Also called ambient noise compensator and SPL (sound pressure level) controller

levels Terms used to describe relative audio signal levels: (Also see decibel).

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

line-level Standard +4 dBu (pro) or -10 dBV (consumer) audio levels. See decibel.

instrument-level Nominal signal from musical instruments using electrical pick-ups. Varies widely, from very low mic-levels to quite large line-levels.

lexicographer The author of a lexicon or dictionary. "Every other author may aspire to praise; the lexicographer can only hope to escape reproach; and even this negative recompense has been yet granted to very few." — Samuel Johnson, 1755.

Leyland number Mathematics. Any number that can be expressed as xy+ yx, e.g., 593 = 29 + 92. Hit the link to see other examples.

LFD (low-frequency diffusion) Acoustics.

LFE (low frequency effects) [Note: it is "effects" NOT "enhancement".) Popularly called bass management, but this is technically wrong. The "point-one" in "5.1 surround systems". It refers to the limited bandwidth (20-90 Hz, 20-120 Hz, or 20-150 Hz depending on the encoding system) special effects/feature channel, but can also refer to a subwoofer channel. Both Dolby Digital and DTS Consumer use the term. The "bass management" part comes from having the option of leaving the bass in the five full-range channels or sending all the lower bass to the subwoofer, or some combination.

LFO (low frequency oscillator) Synthesizers. A very low frequency (less than 10 Hz) sine wave oscillator used to slowly vary other parameters to create effects like flanging and tremolo, or vibrato.

licorice stick Clarinet. [Decharne]

LIDAR (light detection and ranging) A system based on the same principles as RADAR developed for locating, ranging and profiling applications.

lift/dip Popular European term meaning boost/cut.

light organ Electronic device popular in the '60s and '70s where different colored lights would flash in response to different musical frequencies. Contrast with color organ.

light pipe or light guide A device made from optical plastic that couples light from a source (usually a surface mounted LED) to a user interface panel.

light wave coupling See LWC.

Lilith or Lilith Fair An all-women festival tour begun in 1997 by artist Sarah McLachlan along with Dan Fraser, Marty Diamond and Terry McBride, as a celebration of women in music. History here.

limelight a. An early type of stage light in which lime was heated to incandescence producing brilliant illumination. b. The brilliant white light so produced. Also called calcium light. [AHD]

limestone Acoustics. See: Epidaurus.

limiter A compressor with a fixed ratio of 10:1 or greater. The dynamic action effectively prevents the audio signal from becoming any larger than the threshold setting. For example, if the threshold is set for, say, +16 dBu and the input signal increases by 10 dB to +26 dB, the output only increases by 1 dB to +17 dBu, essentially remaining constant. Used primarily for preventing equipment, media, and transmitter overloads. A limiter is to a compressor what a noise gate is to an expander. See the RaneNote "Dynamics Processors — Technology & Applications."

limp wall Acoustics. A partition having inertia but no stiffness. [Morfey]

line arrays Loudspeakers. (also called articulated line arrays) A vertical line (or linear) configuration for large venue multi-cabinet loudspeaker systems creating tight (and steerable) beamwidth coverage (degrees of arc for the propagating sound wave, vertically and horizontally). Favored for their controlled directivity that reduces room reflections and produces less reverberation and improved sound intelligibility, as well as reducing the sound that bleeds back onto the performers. The three most popular configurations are (a) uniform array: typically 2-8 boxes arranged in a flat straight line popular in smaller venues and usually tilted downward above the audience; (b) constant splay array: forms a smooth arc by tilting each box the same amount (pitch) resulting in a wider beamwidth popular in concert hall settings, particularly those with balconies; (c) progressive splay array: combines both previous examples by starting out with a straight flat array that gradually creates an arc at the lower end, forming the letter "J" like shape. Popular for large arenas and concert settings. Individual and unique variations are offered by all major loudspeaker companies.

linear array transducer See LAT.

linear distortion Any change to the amplitude or phase of the incoming signal frequency components. Contrast with nonlinear distortion.

linear PCM A pulse code modulation system in which the signal is converted directly to a PCM word without companding, or other processing.

linear phase response Any system which accurately preserves phase relationships between frequencies, i.e., that exhibits pure delay. See group delay.

linear system or linear device A system or device that meets two criteria: 1) proportionality — the output smoothly follows the input; 2) additivity — if input x results in output U and input y results in output V, then input x+y must result in output U+V. This means the system or device is predictably and its cause and effect relationship is proportional. Contrast: nonlinear.

linear taper See potentiometer.

linear time code See time code.

linearity error Electronics. The maximum permissible deviation of the actual output quantity from a reference curve or line. Think of it as an error-window surrounding the reference: anywhere inside is okay, anywhere outside is not. The size of the window is the linearity error.

line driver A balanced output stage designed to interface and drive long lines. Long output lines tax output stages in terms of stability and current demands. Designs vary from direct-drive differential (sometimes using cross-coupled techniques) to transformer drive. See the RaneNote Practical Line Driving Current Requirements.

line echo canceller See echo canceller.

line-level See levels.

line source arrays See: line arrays.

line spectrum A spectrum containing only discrete frequency components. [Harris]

linguistics The study of the nature, structure, and variation of language, including phonetics, phonology, morphology, syntax, semantics, sociolinguistics, and pragmatics. [AHD]

Linkwitz-Riley crossover The de facto standard for professional audio active crossovers is the 4th-order (24 dB/octave slopes) Linkwitz-Riley (LR-4) design. Consisting of cascaded 2nd-order Butterworth low-pass filters, the LR-4 represents a vast improvement over the previous 3rd-order (18 dB/octave) Butterworth standard. Named after S. Linkwitz, a Hewlett-Packard engineer at that time, who first described the problems and solution in his paper "Active Crossover Networks for Non-coincident Drivers," J. Audio Eng. Soc., vol. 24, Jan/Feb 1976, pp. 2-8. In this paper, he credited his co-worker Russ Riley for the idea that cascaded Butterworth filters met all his crossover requirements. Their effort became known as the Linkwitz-Riley alignment. Linkwitz showed that a significant weakness of the Butterworth design was the behavior of the combined acoustic lobe along the vertical axis. An acoustic lobe results when both drivers operate together reproducing the crossover frequency band, and in the Butterworth case it exhibits severe peaking and is not on-axis (it tilts toward the lagging driver). Linkwitz showed that this results from the Butterworth outputs not being in-phase. Riley demonstrated an elegant solution by cascading two 2nd-order (any even-ordered pair works) Butterworth filters, which produced outputs that were always in-phase and summed to a constant-voltage response. Thus was created a better crossover. See the RaneNote Linkwitz-Riley Crossovers: A Primer and RaneNote Signal Processing Fundamentals.

Linux A computer Unix-type operating system (OS) invented by Linus Torvalds in 1992, who wrote it as a student at the University of Helsinki. He created this OS because he couldn't afford one that could accomplish what he wanted with his available hardware. He then posted it on the network for other students, where it grew and became very stable and powerful. Today, for free, the software, source code, etc., is available off the Web.

LIPA (Liverpool Institute for Performing Arts) A state-of-the-art performing arts higher education institution co-founded by Paul McCartney and Mark Featherstone-Witty; located in a renovated old school that McCartney went to. History here.

Lissajous figure also Lissajous curve and Bowditch curve (after Nathaniel Bowditch, in 1815 who first studied these curves) Oscilloscopes. A special case of X-Y plot in which the signals applied to both axes are sinusoidal functions. For a stable display the signals must be harmonics. Lissajous figures are useful for determining phase and harmonic relationships. (After J. A. Lissajous) [IEEE] For some educational fun check out Lissajous Lab. Also fun is Crop Circles of Consciousness.

Lissajous, Jules Antoine (1822-1880) French mathematician.

listen has the same letters as silent.

listening "It is the province of knowledge to speak and it is the privilege of wisdom to listen." Oliver Wendel Holmes [Crystal]

liter Abbr. l or lit. A metric unit of volume equal to approximately 1.056 liquid quarts, 0.908 dry quart, or 0.264 gallon. [AHD]

Little Kids Rock A nonprofit organization that "... provides weekly music education classes to K-12 students in public schools that have been stripped of their music programs." [from website] Amazing and valuable group.

Little Willie Littlefield (1931-2013) American musician famous as a blues singer and boogie-woogie pianist who recorded the first version of "Kansas City." Early pioneer of merging boogie-woogie and rock 'n' roll music techniques.

litz wire Derived and shortened from the German word "litzendraht" meaning strand, or woven wire. It is a cable constructed of individually insulated magnet wires either twisted or braided into a uniform pattern, which increases the total surface area compared to an equivalent solid conductor. The pattern is formed to reduce skin effect by guaranteeing that along a significant length, any single conductor will be, for some portion of its length, located in the center, the middle, and the outer portion of the bundle. This transposition prevents any one conductor from being subject to the full forces of magnetic flux, thereby reducing the effective resistance of the entire bundle. Litz wire bundles of 50, 100 or even more conductors are available. They are constructed by winding smaller bundles of six conductors into larger bundles. Those bundles may be "litzed" with other bundles to create progressively larger cables. Litz constructions counteract skin effect by increasing the amount of surface area without significantly increasing the size of the conductor.

liuqin Musical Instrument. Chinese 4-string mandolin.

live room Acoustics. A room characterized by a relatively small amount of sound absorption. [Harris]

live sound See: History of Concert Sound.

LKFS (loudness K-weighted digital full scale) Broadcast. A standard ( ITU R BS.1770-2) aimed at normalizing broadcast loudness levels. An increase of 1 dB in signal level will cause the loudness reading to increase by 1 LKFS. For a particularly good overview see: Florian Camerer's paper, "On the way to Loudness nirvana: audio levelling with EBU R128." Also see: LUFS.

LL Cool J (Ladies love cool James) Birth name: James Todd Smith.

load Electronics. A device or the resistance of a device to which power is delivered. [AHD]

load shedding Power Supplies. Term for any sort of automatic rationing of available power when demand exceeds capacity. When power companies do this it is commonly called a rolling blackout.

lobing error Electronic crossovers. The amount of on-axis deviation in amplitude from zero (i.e., perfect combined radiation pattern) resulting from phase deviations at the crossover point. Term coined by Lipshitz, Stanley P. and John Vanderkooy, "A Family of Linear-Phase Crossover Networks of High Slope Derived by Time Delay," J. Audio Eng. Soc., Vol. 31, No. 1/2, January/February 1983, pp. 2-20). See the RaneNote Linkwitz-Riley Crossovers: A Primer.

lodestone (also loadstone) A piece of magnetite that has magnetic properties and attracts iron or steel. [AHD]

Lodge, Oliver Joseph (1851-1940) Knighted British physicist who, in 1898, gained a patent on the moving-coil loudspeaker, utilizing a coil connected to a diaphragm, suspended in a magnetic field (British patent 9,712/98).

Loft Scene Musical jazz and early hip-hop phenomenon occurring in New York city during the '70s, where people would dance and party in renovated old industrial loft spaces.

log Short for logarithm.

logarithm Mathematics. A shortcut method that uses the powers of 10 (or some other base) to represent the actual number. The logarithm is the power to which a base, such as 10, must be raised to produce a given number. For example, 10³ = 1,000; therefore, log (to the base 10) 1,000 = 3. The types most often used are the common logarithm (base 10), the natural logarithm (base e), and the binary logarithm (base 2).

logic A system of reasoning first formulated by Aristotle. 1. The study of the principles of reasoning, especially of the structure of propositions as distinguished from their content and of method and validity in deductive reasoning. Computer Science
a. The nonarithmetic operations performed by a computer, such as sorting, comparing, and matching, that involve yes-no decisions. b. Computer circuitry. c. Graphic representation of computer circuitry. [AHD

log taper See potentiometer.

Lollapalooza Chicago's biggest music festival (ahead of Pitchfork) usually held in August.

Long, Richard (1933-1986) Founder of RLA (Richard Long and Associates), dance club sound designers during the disco heydays of the '70s and '80s. Richard's success grew out of his experience working as the sound engineer for the Paradise Garage in Greenwich Village during the mid-seventies. After developing his chops at the Paradise Garage, Richard designed many famous dance clubs including Studio 54, Annabel's (London), Regine's (a chain of 19 clubs scattered around the world from Paris and NY to Cairo) and many others that were the vanguard of the disco era. Indeed, continuing years beyond Richard's unfortunate death in 1986, his designs flourish today in such icons as the Ministry of Sound (London). Further information available at GSA and see Richard and Alan Fierstein's seminal paper "State-of-the-Art Discotheque Sound Systems — System Design and Acoustical Measurement," presented at the 67th Convention of the Audio Engineering Society, New York , 1980, preprint 1694.

Longacre Square Original name for Times Square; renamed in 1904.

longitudinal Of or relating to longitude or length. [AHD]

long-tailed pair Analog Electronics. The most common form of differential amplifier usually consisting of a top-side current mirror and a constant bias current source tied to the common emitters point, forming the "tail." First designed and patented by Alan Blumlein (wasn't everything!) in 1936 as an amplifier for small signals.

loop Electronic circuits. A closed circuit, i.e., a set of branches forming a closed current path, provided that the omission of any branch eliminates the closed path. An electric circuit providing an uninterrupted path for the flow of current.

loopback address Internet. Pinging yourself by using IP address

loquacious Very talkative; garrulous. [AHD]

Lorentz force Physics. The orthogonal (right angle) force on a charged particle traveling in a magnetic field, named after H. A. Lorentz. [AHD]

Lorentz, Hendrik Antoon (1853-1928) Dutch physicist, famous for the Lorentz force and co-receiving a Nobel Prize for researching the influence of magnetism on radiation. [AHD]

loss See gain.

lossless See digital audio data compression

lossy See digital audio data compression.

loud Having offensively bright colors: a loud necktie. [AHD]

loudness The SPL of a standard sound which appears to be as loud as the unknown. Loudness level is measured in phons and equals the equivalent SPL in dB of the standard. [For example, a sound judged as loud as a 40 dB-SPL 1 kHz tone has a loudness level of 40 phons. Also, it takes 10 phons (an increase of 10 dB-SPL) to be judged twice as loud.] Note that loudness is a subjective measurement; contrast with intensity which is an objective measurement.

loudness curve See Fletcher-Munson.

loudspeaker, acoustic suspension See: acoustic suspension loudspeaker.

loudspeaker Dynamic. An electromagnetic transducer based on the principle of electromagnetic induction used to convert the electrical energy output of a power amplifier into acoustic energy. The heart of a dynamic loudspeaker is a coil of wire (the voice coil), a magnet, and a cone. The amplifier applies voltage to the voice coil causing a current to flow that produces a magnetic field that reacts with the stationary magnet making the cone move proportional to the applied audio signal.
Other loudspeaker technologies exist, among these are electrostatic (a thin sheet of plastic film suspended between two wire grids or screens; the film is conductive and charged with a high voltage; the film is alternately attracted to one grid and then the other resulting in motion that radiates sound), but for pro audio applications, dynamic loudspeakers dominate. The first loudspeaker was patented by Ernst Siemens in 1877, and Lodge obtained a UK patent in 1898. See also ribbon tweeter and back-emf.

loudspeaker directivity See: Q.

Loudspeaker Health Care Fun and educational tips developed by MC2 System Design Group. [Check it out, you won't be disappointed.]

loudspeaker line arrays See line arrays.

loudspeaker measurements See AES2.

loudspeaker model See amplifier dummy load.

loudspeaker reconing See reconing.

loudspeaker sensitivity See sensitivity.

loudspeaker surround See surround.

Love Parade Music festival begun in 1989 after the fall of the Berlin wall to celebrate solidarity and freedom, became a huge EDM event, peaking at over 1.5 million people, which in 2010 resulted in 21 deaths and over 500 injured people; now permanently cancelled.

low-cut filter also lo-cut filter See high-pass filter [In audio electronics, we define things like this just to make sure you're paying attention.] Contrast with low-pass filter below.

low impedance Abbr. Lo-Z Electronics. A device having an electrical impedance of at less than 1,000 ohms. [Note: This value is arbitrary as there is no standard defining exactly what constitutes a 'low impedance.'] Examples include loudspeakers in the 4-16 ohms range; headphones from 32-150 ohms; microphones rated 50-600 ohms; and electronic circuit outputs are low-impedance, rated at 50-300 ohms. Contrast with high impedance.

low-pass filter also lo-pass filter A filter having a passband extending from DC (zero Hz) to some finite cutoff frequency (not infinite). A filter with a characteristic that allows all frequencies below a specified rolloff frequency to pass and attenuate all frequencies above. Anti-aliasing and anti-imaging filters are low-pass filters. Also known as a high-cut filter.

low voltage Electricity. A term with many definitions, some of which surprise, like that 1000 Vac is considered "low voltage" by the IEC.

low-voltage system Electric Power. An electric system having a maximum root-mean-square alternating-current voltage of 1000 V or less. [IEEE]

Lo-Z See low impedance.

LP (long play) Phonograph Records. The name for the 33 1/3 rpm vinyl record introduced by Columbia Records in 1948.

L-pad See attenuator pad.

LRAD (long range acoustic device) A non-lethal sonic communicator/weapon developed by American Technology Corporation capable of producing sound pressure levels of 153 dB-SPL.

LRC (inductance-resistance-capacitance) Electronics. Shorthand for the most common passive circuit elements. Also seen as RLC, LCR, CRL, etc.

LSB (least significant bit) The bit within a digital word that represents the smallest possible coded value; hence, the LSB is a measure of precision.

LTC (linear time code) See time code.

LUFS (loudness unit digital Full Scale) Alternate term for LKFS.

Lully, Jean-Baptiste (1632-1687) French composer. [AHD]

The baton used by a seventeenth-century conductor was a much longer and heavier affair than the little wand used today. On January 8, 1687, in the course of conducting a Te Deum, Lully struck his foot with his baton, injuring it so seriously that gangrene set in and he died ten weeks later. [Bartlett's Book of Anecdotes]

Lumière, Auguste and Louis French brothers who invented the "cinematograph," reportedly the first all-in-one camera/projector/printer, in 1895.

luminance 1. Abbreviated Y. That part of the video signal that carries the information on how bright the TV signal is to be. The black and white signal. 2. VJ Jargon. A filter that controls the video brightness. Used to blend clips by limiting the bright or dark image pixels. See chrominance.

Lunchbox Nickname for the narrow 500 Series of modular card frame racks. Coined by Art Kelm. "API Lunchbox" is a registered trademark of API Audio.

lute Musical Instruments. A stringed instrument having a body shaped like a pear sliced lengthwise and a neck with a fretted fingerboard that is usually bent just below the tuning pegs. [AHD]

LWC (light wave coupling) Electronic Displays. Experimental very flexible flat panel display technology under development at Extreme Photonix, a University of Cincinnati spin-off from their Nanoelectronics Laboratory.

Lynyrd Skynyrd American rock band who took their name from their high school gym teacher, Leonard Skinner, as a way of mocking him, since he was a strict disciplinarian and had their guitarist, Gary Rossington, kicked out of school for having hair too long.

lyra Musical Instruments. Three stringed bowed instrument with a bowl back carved from the solid. Popular in Greece and the Balkans.

lyre Musical Instruments. A stringed instrument of the harp family having two curved arms connected at the upper end by a crossbar, used to accompany a singer or reciter of poetry, especially in ancient Greece. [AHD] One of the oldest known musical instruments dating back to the Sumerians.

lyric French word literally meaning of a lyre; the words of a song.

lyrical putty "The lyrics one creates in one's head in the absence of knowing a song's real lyrics." [A Dictionary of the Near Future by Douglas Coupland, NY Times, September 12, 2010.]

AES - Audio Engineering Society