label – (1) A round paper disc in the center of a phonograph record that provides the title, artist, manufacturer, and other information about the record. (2) A distinctive brand used by a record company to market its catalog of music. (3) The record company itself, also known as a record label.
lacquer – (1) A liquid consisting of a resin, nitrocellulose ester, or other material dissolved in a solvent, that dries to form a hard protective coating on wood and metal. It is also used in vinyl mastering and CD manufacturing, as well as for creating test discs (called a “lacquers” or “acetates”). (2) The name preferred by the recording industry for an acetate disc.
lacquer master – a nitrocellulose lacquer-coated aluminum disc 14 inches in diameter (for a 12-inch LP) that has had grooves cut with a lathe that contains the final mastered recording (equalized to the RIAA curve). It is the first step in in the manufacture of vinyl discs. After the lacquer master is sprayed with silver nitrate to fill all the grooves, it is submerged into a nickel sulfamate solution and nickel is electroplated onto the disc plate. After about 90 minutes, the disc is removed from the bath and the nickel-metal negative is separated from the lacquer master to create the metal stamper. Sometimes called a master disc. See vinyl mastering.
lag time – see time delay. LAME – a free software trackcodec used to encode and compress audio into the lossyMP3 file format, developed by Mike Cheng, beginning in about 1998, with LAME 1.0, and later improved as LAME 2.0. The goal was to improve upon the original codec developed by the Fraunhofer Society, including an improved psychoacoustic model, variable bit rates, and improved speed. Because LAME uses some technology covered by patents owned by Fraunhofer, some patent disputes have arisen.
lap steel guitar – a type of guitar that is placed horizontally on the lap with the strings being plucked with one hand, while the other hand changes the pitch of one or more strings using a bar or slide called a steel. The term lap steel is used to differentiate between it and a pedal steel guitar. Called lap steel for short.
large-diaphragm condenser – a condenser microphone with a large diaphragm, typically larger than ¾ inch, although there is no strict size definition. Microphones with large condensers are generally considered to have a pleasing sound with more character than those with small diaphragms. For this reason, they are often the mic of choice for vocals. Although large diaphragms are generally more sensitive than smaller ones due to the increased surface area, they are no better at capturing low frequencies than small diaphragm condensers, contrary to popular opinion. Abbreviated as LDC. See also medium diaphragm condenser.
laser (Light Amplification by Stimulated Emission of Radiation) – a device that produces an intense beam of coherent, monochromatic light by stimulating atoms to emit photons. Lasers are used many applications, such as reading bar codes and in recording and playing compact discs. It was invented at Bell Laboratories.
LaserDisc – a home video format on a 30-cm (11.81-in) optical disc that provided playback of analog video that was of higher quality than that of competing formats (VHS and Betamax videocassette). The LaserDisc system never gained widespread use in North America, primarily because of the high cost, both of the players and the video titles. The technology and concepts of the LaserDisc became the foundation for later optical disc formats, such as the compact disc, DVD, and Blu-ray Disc.
laser microphone – a device that uses a laser beam to detect sound vibrations in an object at some distance. Its primary purpose is for eavesdropping without being detected.
latency – the delay between the input and the output of an audio signal due to the time it takes a computer to process the signal, plug-ins, and other processes, as well as using other hardware.
late reflections – the reflected sound waves that reach a listener after the early reflections, variously defined as those arriving 80 to 100 ms or more after the direct sound. The late reflections bounce off many surfaces and tend to be dense, very diffuse, and make up the majority of the reverberant sound. Also called later reflections, reverberant tail, reveration tail, or reverb tail.
lathe – a device for cutting grooves into a master for making vinyl records. The grooves contain vibrations that are cut in response to the audio being encoded into master. Also called a cutting lathe, vinyl cutting lathe, or mastering lathe. See also direct metal mastering.
lavalier mic – is a small microphone that is worn on clothing or hung around the neck. Sometimes called a lapel mic.
law of magnetic poles – the rule that states that like magnetic poles poles repel and unlike poles attract.
layback – the process of combining video with its audiosoundtrack. Audio and video are normally edited separately and once each is finalized, they are combined to complete the final project. See also layover, layoff, and prelay.
layer – to play or record several similar musical parts over one another, either at the same time or separately.
Layered Sound™ – trademark for a patented, innovative method of using two types of loudspeakers to create a natural-sounding soundfield. Natural sound is made up of two types of sound waves, binaurally correlated and binaurally de-correlated waves. Binaurally correlated sound waves are highly coherent, and allows a person to determine the location of a sound. With binaurally de-correlated waves, it is difficult to locate the source of the sound. Conventional dynamic loudspeakers create longitudinal sound waves that are perceived as direct sound, while transverse-wave resonating panel (TWRP) loudspeakers create transverse sound waves that are highly diffuse and incoherent and are perceived as reflected sound. When the direct and reflected sounds are properly combined, an immersive effect is created that sounds natural. Layered Sound produces a smooth frequency response and creates a broad layer of diffuse and evenly dispersed sound. The sound image and localization of sounds is improved, resulting in a significant improvement in clarity, intelligibility, and sound quality that does not depend on whether the sound source is live, recorded, or a combination of the two.
layering – the playing or recording of several similar musical parts over one another, either at the same time or separately. See also double tracking and multitrack recording.
lay length – the distance, parallel to the axis of a cable, in which a strand of wires in the shield completes one complete turn about the axis. Shorter lay lengths provide better rejection of electromagnetic interference, but make the cable less flexible and more expensive. Also called pitch length.
LCRS – Left, Center, Right, Surround. The four surround sound channels originally used in 35-mm motion pictures. These were later replaced by 5.1 systems, where the S channel was replaced with LS and RS.
leading tone – (1) A note or pitch that resolves (leads) to a note one semitone higher or lower, which is a lower leading tone or upper leading tone, respectively. (2) The seventh note of a diatonic scale, which leads melodically upward to the tonic, one semitone above it. For example, for the C major scale the leading tone is the note B, which leads to the tonic C. Also called a leading note or subsemitone.
LEDE™ – Live End/Dead End. A trademark of Synergetic Audio Concepts for a type of control room design in which early reflections at the listening position are controlled in the front half of the room and sounds are diffused to the listening position in the back half of the room. It has largely been replaced by RFZ, ESS, non-environment, and controlled image designs.
ledger line – in music notation, short lines added to accommodate notes that appear above or below the staff. For example, middle C is shown on a ledger line below the treble clef staff and above the bass clef staff.
legato – (1) To play a series of notes contiguously with no gaps between them. It differs from portamento and glissando, in which the notes are played contiguously by sliding from one note to the next. The musical notation for legato is a slur. Legato is Italian for “tied together.” (2) A setting on some synthesizers that causes notes to be played in a legato style.
Leslie™ loudspeaker – a loudspeaker designed by Don Leslie in the 1940s which became famous because of its use with the Hammond B-3 organ. Used by many rock groups in the 1960s and 1970s, the Leslie speaker produced a swirling, pitch-shifting sound, created with a fixed loudspeaker and a rotating horn assembly to produce the effect. Also called a Leslie cabinet, Leslie rotary speaker, or simply rotary speaker..
letterboxing – displaying a video with black bars on the top and bottom of the image to accommodate images of differing aspect ratios, such as a 2.35:1 widescreen image displayed on a 16 x 9 (1:78:1) screen. See also pillarboxing and windowboxing.
leveler – a device that maintains an audio signal at a somewhat constant level. While similar to a compressor, a leveler circuit is not specifically designed to reduce the dynamic range of a signal, although it sometimes does. A leveler is also similar to an automatic gain control (AGC), but normally works better and with more transparently than ta typical AGC control. Also called a leveling amplifier.
level indicator – a meter used to measure and adjust audio signals in a recording device. Also called a level meter.
Lexicon – a compny founded in 1971 and headquartered in Waltham, MA that designed and manufactured audio equipment for the professional and consumer including home theater equipment. In 1993, the company was acquired by Harman International Industries (HII) of Salt Lake City, UT.
Lexicon 480L Digital Effects System™ – a hardware signal processor unit introduced by Lexicon in 1986. It is widely considered one of the best-sounding reverb units ever built.
LFO – Low Frequency Oscillator. A controller that produces slow oscillations to control another signal.
LFE – Low Frequency Effects. The special effects and features channel in a 5.1surround sound system—the “point-one” portion. It carried the low bandwidth (less than 120 Hz) and other effects. Sometimes incorrectly called bass management.
library music – recorded music that can be licensed to clients for use in film, television, radio and other media. Usually, libray music is owned and maintained in production music libraries by companies that create the music or acquired it from third parties. Also known as stock music or production music.
Lightpipe – a trademakr for an optical cable developed by Alesis. Alesis coined the term “Lightpipe” to help distinguish between their proprietary eight-channel optical cables used in their ADAT devices and the two-channel optical cables used on CD players and other consumer products. This system has since been adopted by other manufacturers for transferring digitalsignals between other types of audio devices. Sometimes spelled Light Pipe. Sometimes called light guide. See ADAT-DOIand TOSlink.
line array – a loudspeaker system consisiting of several loudspeaker elements that are usually identical and mounted typically in a vertical line to produce a fairly evenly distributed sound pattern to the audience at a live venue. Also called a loudspeaker array, loudspeaker stack, cluster, or simply an array.
line level – (1) With balanced equipment (most profession recording equipment) a signal with a level of approximately 1.23 volts (+4 dBu). (2) With unbalanced equipment (most consumer equipment or semi-profession recording equipment) a signal with a level of 0.316 volts (-10 dBV). Note: A microphone input, which usually uses a balancedXLR connector, is designed for low level signals that must be boosted with a preamp to be usable by audio equipment. Line level inputs, which are much higher than mic level signals, usually use ¼-inch connectors and normally do not need preamplification. See also signal level.
line noise – any noise that occurs in the electric power supply, such as 60-cycle hum (50-cycles in some countries) and spurious spikes that occur when other equipment, usually within the same facility, is switched on or off.
link – to set up a signal processor in such a manner that it acts in a similar manner upon two or more channels simultaneously.
link key – a code shared by two Bluetooth devices in order to established a secure relationship during the pairing process.
Linkwitz-Riley filter – a type of active audio crossover developed by Siegfried Linkwitz and Russ Riley, consisting of a parallel combination of low-pass and high-pass filters. Also called a Butterworth squared filter. Abbreviated as L-R.
liquid crystal (LC) – an organic liquid that acts as a liquid but resembles a crystal by having some ordered molecular arrays similar to a regular crystalline lattice that refracts light.
liquid-crystal display (LCD) – a flat panel display used in electronic devices consisting of a layer of liquid crystal material sandwiched between two transparent electrodes. The application of an electric current to a small area of the liquid crystal changes the alignment of its molecules, which changes the character of transmission or reflection of polarized light. Liquid crystals do not emit light directly.
Lissajous figure – an x-y curve made by an oscilloscope tracing out two simple harmonic motions in mutually perpendicular directions, the shape of which indicates the characteristic of the relative phases and frequencies of the motions. In audio these curves help determine the phase of a microphone. It is named after French physicist Jules A. Lissajous. Also called a Lissajous curve or an X-Y function.
litz wire – a type of cable used in electronics that carries alternating current, consisting of many strands of thin wire that are individually insulated and twisted or woven together, in a special pattern. There are several such winding patterns, which are designed to equalize the amount that the overall length of each strand is on the outside of the conductor. This does not occur with simple twisted-strand wire. The purpose of litz wire is to minimize the skin effect and proximity effect at high frequencies. The term litz comes from Litzendraht, German for “braided“ or ”stranded wire.”
live performance – (1) A theatrical play or musical performed live before an audience. (2) A music concert perfomed live before an audience. (3) A dance performed for an audience. (4) A radioprogrambroadcast live as it takes place. (5) A television program broadcast live in real-time, as it happens.
Livewire+ – an audio-over-ethernet (AoE) protocol created by Axia Audio, a division of the Telos Alliance. It is used for routing and distributing broadcast-quality audio in radio stations. Livewire was introduced in 2003, but was improved to Livewire+ that enabled full compatability with AES67. Sometimes shown as Livewire+ AES67.
LKFS – Loudness, K-weighted, Full Scale. A loudness unit referenced to digital full scale used with the ITU BS.1770 standard for loudness normalization of audio levels used in broadcast TV and other video sources. LKFS is the preferred term used by ATSC as in ATSC A/85, while the EBU prefers the term LUFS, as in EBU R128. Althought there was originally a sligth diffenece in the two terms, they are now essentially the same.
Lmax/Lmin – two measurements used to determine the dynamic range of a recording. Lmax is the maximum measured level of the recording, and Lmin is the minimum level. The dynamic range of an audio signal is Lmax - Lmin.
load – (1) The power consumed by a circuit. (2) In general, a component, circuit, or device that consumes electric power. Also called an electrical load. In audio, it is the circuit or device (or its input impedance) to which a signal is connected. For example, if a CD player is connected to an amplifier that is connected to a speaker, the amplifier is the load for the CD player and the speaker is the load for the amplifier. It is not safe to operate a tube amplifier without a speaker connected, as it can be damaged with no load. If an amplifier must be operated silently or with no speaker, a dummy load must be used. A dummy load absorbs the power and dissipates it as heat without producing sound. There are two basic kinds of dummy loads: resistive load and reactive load. The resistive load is the most common and consists of a combination of resistors. The reactive load consists of a network of resistors and capacitors that emulates the impedance curve of a speaker. A reactive load is usually more expensive than a passive resistor-based load, but it is supposed to provide results closer to that of a speaker.
lobar pattern – a type of pickup pattern that is slightly more directional than supercardioid or hypercardiod patterns. It is achieved only with shotgun microphones and has the highest possible directivity. Although a lobar polar pattern is sometimes referred to as a supercardioid/lobar or hypercardioid/lobar pattern, both the supercardioid and hypercardioid patterns have a wider pick up pattern than the lobar pattern. Also called a shotgun pattern or a line and gradient pattern. See also polar pattern.
lobes – the round-shaped areas of highest sensitivity in the polar pattern of a microphone. For example, the bi-directional polar diagram of a figure-eight microphone shows two equal-sized lobes 180 degrees apart.
local area network (LAN) – a group (network ) of computers and computer devices that share a common communication link within relatively small area, such as a building or nearby buildings. See also wide area network (WAN).
local control – a switch on many MIDIkeyboards that determines whether a MIDI device responds to its own keyboard and controllers (local control on) or to incoming MIDI messages from an external source (local control off). Also called local on and local off.
localization – (1) The ability of human hearing to perceive the location or direction of a sound source. Because of the head shadow, a sound reaches the ear turned away from a sound (the shadowed ear) with much less intensity than the ear turned toward it, resulting in an interaural level difference (ILD) or interaural intensity difference (IID). The shadowed ear also receives a sound slightly later, resulting in an interaural time difference. A 1000-Hz tone that reaches the left ear 0.5 ms before the right ear will be 180 degrees out of phase with the wave reaching the right ear, an interaural phase difference (IPD). These differences are factors the human brain uses for sound localization. For frequencies below 1000 Hz, the ITD has he greatest effect. For frequencies above 1500 Hz, the IID becomes the main factor. There is a transition zone between 1000 Hz and 1500 Hz where both mechanisms play a role. Also called sound localization. (2) The creation of phantom images at specific locations across a soundstage. See also stereo imaging
locked groove – the continuous loop at the end of the runout groove near the center of a record that keeps the stylus from running into the label. Locked grooves are usually silent, but can contain about 1.5 seconds of music at 33⅓ rpm (1 second at 45 rpm) that repeats until you pick up the needle. Also called a lockout groove.
lock up – (1) The condition in which two devices are synchronized with the master controlling the slave so their clocks are synced and running together. While digital devices can be locked, analog devices cannot. (2) A condition in which a computer or computer-controlled device crashes or freezes up, becoming unresponsive and requiring a reboot.
Locrian mode – one of the seven musical modes or scales with the interval pattern of semitone-tone-tone-semitone-tone-tone-tone.
logarithm – a mathematical concept developed by John Napier in the early 17th century as a means to simplify calculations. The logarithm of a number is the exponent to which a second number (the base) is raised to produce the first number. For example, the logarithm of 1000 to base 10 is 3, because 103 is 1000. A logarithm using the base 10 is called the common logarithm, usually shown as log or log10. The natural logarithm uses e (Euler's number, equal to approximately 2.718...) as its base, and is usually indicated as ln.
log-periodic antenna – a broadband, multi-element, directional, narrow-beam antenna that has transmission characteristics that repeat regularly as a logarithmic function of the radiofrequency.
Lombard effect – the involuntary tendency, discovered in 1909 by French scientist Étienne Lombard, that a speaker has to increase his or her vocal effort to enhance audibility when speaking in a loud, noisy environment. Changes include not only loudness but other effects, such as pitch, rate, and duration of syllables. Also known as the Lombard reflex.
longest dimension rule – a rule of thumb for estimating the starting distance for microphone placement with acoustic instruments, which states that the microphone should be placed at a distance equal to the longest dimension of the part of the instrument that produces sound. This distance should be adjusted as necessary to capture the desired tone. For example, the body of an upright bass is about four feet long, so start by placing the microphone about four feet away from the bass.
longitudinal wave – a wave in which the displacement of the medium is in the same direction as (or the opposite direction to) the direction of propagation of the wave, as opposed to a transverse wave, in which the displacement of the medium is at right angles to the direction of propagation. Sound waves are longitudinal.
loop – (1) A magnetic recording tape with the ends spliced together so that it will continuously repeat on playback. (2) A sample of audio consisting of a few measures or a short pattern that can be inserted into a track of a recording so that when it is played back it plays seamlessly as if it were one continuous performance. Also called an audio loop, sample loop, or clip. See looping. (3) To play or record a section of audio repeatedly.
looping – the process of repetedly inserting small sections (called loops or clips) of audio or MIDI data (typically one to four measures) into a track so that when it is played back it plays seamlessly as if it were one continuous performance.
loop overdub – new material that is added to (overdubbed) to previous loops using a looper, to create a layered effect or a fuller sound.
loop quantization – a function found on some loopers that synchronizes the start of loops and makes sure they are timed properly.
loop recording – a function in some DAWs where a specific section of a track can be recorded repeatedly in a loop. At the end of the selected section, the recording automatically jumps back to the beginning of the section and records a new take on a new lane. This allows multiple takes to be recorded so the best one can be chosen or used to create a comp track. See also playlist.
loose cue – a method of cueing a record by placing the stylus just before the cue point, turning off the turntable, and then rotating it backward one quarter to one half revolution. When it is time to be played, the turntable is turned on and quickly comes up to speed and starts playing at the desired point. This method is not as tight as the slip cue.
Lo/Ro – Left only/Right only. A standard left-right stereo signal that has been downmixed from a larger format mix, such as 5.1. Because the surround information has not been incorporated into the stereo signal with matrix encoding, a Lo/Ro signal cannot be subsequently decoded back into the larger format. Sometimes written Lo-Ro. Compare with Lt/Rt.
loss – the amount of decrease in the strength of an audio signal, usually expressed in decibels (db). The opposite of gain.
lossless – a type of data compression that uses an algorithm that can perfectly reconstruct the the original data from the compressed data, as opposed to a lossy data compression that can only approximate the original data.
loss of lubricant – a term for a magnetic recording tapes that squeals on playback and exhibits a white powdery residue. The term is now considered a misnomer since lubricant loss is not actually the cause of the problem, but the actual cause is not fully understood. Unlike tapes with sticky-shed syndrome, tapes with loss of lubricant do not respond to baking.
lossy – a type of data compression that uses an algorithm that reconstructs an approximation of the the original data from the compressed data, as opposed to a lossless data compression that can perfectly reconstruct the original data. A lossy compression scheme uses perceptual coding or other methods to remove data that will most likely not be missed in order to significantly reduce file size.
loudness – (1) The quality that the human ear perceives as the strength of a sound, a psychoacoustical perception. (How loud something sounds to the ear.) A general “rule of thumb” for loudness is that the strength of a sound must increase by a factor of ten to sound twice as loud. Loudness is affected by a number of parameters other than sound pressure, including the frequency, bandwidth, spectral composition, and the duration the sound. The same sound pressure level (SPL) does not create the same loudness perception by all individuals. The sone is the unit used to describe loudness and the phon is the unit used to describe loudness level. Loudness often is used interchangeably with volume. (2) A type of frequency correction applied to some audio circuits to compensate for the Fletcher-Munson effect—the fact that human hearing varies with the frequency.
loudness level (LN) – a measure of the loudness of a sound as indicated by the logarithm of the loudness. Loudness level (LN) in phons can be calculated by LN = 40 + 33.22 × log N, where N is the loudness in sones, for 1 sone and above. For loudness N less than 1 sone, it is calculated as LN = 40 × (N + 0.0005)0.35.
loudness war – the tendency of the recording industry to release digitally mastered albums with inceasingly higher levels of loudness, sometimes to the point of distortion. The result is decreased sound quality and reduced dynamic range, Several organizations have been formed to combat this problem, including the MLA and PLOUD. Also called the loudness race or level war.
LOUD Technologies, Inc. – a professional audio company headquartered in Woodinville, Washington. It was founded in in Seattle in 1988 by Greg Mackie as Mackie Designs, Inc. to design and manufacture compact pro audio mixers. It went on to design and manufacture professional music and recording equipment, such as mixing consoles, loudspeakers, studio monitors, control surfaces, and digital recording equipment. In 2000, Mackie acquired Eastern Acoustic Works (EAW), which manufactures high-end professional loudspeakers. In 2005, it acquired St. Louis Music, Inc., which began in 1978 making Crate amplifiers for a variety of instruments. St. Louis Music, Inc., had previously purchased Ampeg, a manufacturer of electric guitars and basses and guitar amplifiers in 1986. St. Louis Music also owns Alvarez Guitars, which manufacturers string instruments, including banjos, acoustic guitars, and acoustic bass guitars. In 2003 Mackie Designs, Inc. changed its name to LOUD Technologies, Inc. to avoid confusion between the parent corporation and the Mackie brand. In 2007, it acquired Martin Audio, which manufactures loudspeakers and other audio equipment.
low bass – one of four subdivisions into which bass is sometimes divided, covering the range of 40 Hz to 80 Hz. The other three subdivisions are deep bass (40 Hz to 80 Hz), mid bass (80 Hz to 160 Hz), and upper bass (160 to 350 Hz), although these ranges vary from source to source. See also audio spectrum.
lower toms – a double-headed tom-tom drum which usually stands on the floor on three legs. Also called floor toms.
low frequency – (1) Audio frequencies in the lower region of the audio spectrum. There is no standard definition of low frequency audio, and the frequencies often depend upon the context in which the phrase is used. (2) Low Frequency (LF). The portion of the radio frequency spectrum from about 30 kHz to 300 kHz.
low-power broadcasting – broadcasting from radio and TV stations that operate at a much lower power than standard full-power stations. These are not the same as broadcast translators. Often designated as LPFM (low-power FM radio), LPAM (low-power AM radio), and LPTV (low-power television), they are subject to regulations that vary by country. In 2000 in the US, the Federal Communications Commission (FCC) established LPFM as a new class of radio station for use by non-commercial educational broadcast stations. These stations operate at effective radiated power (ERP) of 1 to 10 watts (Class L2) or at 50 to 100 watts (Class L1). Commercial FM stations operate at 100 watts or more. The FCC does not issue licenses for low-power AM stations, but the term LPAM is sometimes used to refer to unlicensed low-power AM transmissions operated under Part 15. LPTV licenses were created by the Community Broadcasters Act of 1998. They are classified as Class A (LPTV-CA) and low-power digital (LPTV-LD) stations and have an ERP limit of 3 kW for VHF and 15 kilowatts for UHF. Stations that do not have original programming and rebroadcast the programming of other stations are designated as translators (LPTV-TX). See also microbroadcasting (micropower broadcasting).
LP – Long Play. A vinylphonograph record usually 12 inches in diameter (although occasionally 10 inches) and played at 33⅓ rpm, typically having six tracks on a side. These were often called albums until the compact disc began to displace them beginning in 1988. See also EP.
L-pad – a type of electronic attenuatorcircuit with a schematic in the shape of the letter “L.” An L-pad holds either the input impedance or the output impedance constant as the attenuation changes. A T-pad maintains a constant impedance on both the input and output impedance. An H-pad performs the same function as a T-pad, except it is designed for balanced lines. All three attenuate signals independent of the frequency. A speaker L-pad is a special combination of rheostats that control volume while maintaining a constant load impedance on the audio amplifier output. They are called pads because they “pad” down the signal analogous to acoustics. Also spelled L pad.
LTC – Linear Time Code or Longitudinal Time Code. A method of encoding of SMPTE timecode data in an audio signal, which is usually recorded on a separate track or in other storage media.
LTE – Long Term Evolution. A term established used to for a technological path to reach the standards established for 4G wireless phone communications. When the ITU-R set the minimum standards for 4G, they were unattainable at the time. In response, the ITU-R decided that LTE could be labeled as 4G if it provided a substantial improvement over 3G technology. Therefore, many wireless phone providers are able to label their systems as 4G LTE claiming it meets the next-generation in technology without actually meeting the required standards. Although speeds vary by location and network, 4G is definitely an improvement over 3G.
LTO – Linear Tape-Open. An open-format magnetic tape storage technology created by Hewlett-Packard, IBM, and Seagate Technology and introduced in 2000 as an open standards alternative to the proprietary tape formats that were available prior to that. The format has been improved and upgraded over time. Although used primarily as a bcakup for computer data, it is also considered a viable method for backing up and archiving digitalaudio files.
Lt/Rt – Left total/Right total. A standard left-right stereo signal that has been matrixed from a larger format mix, such as 5.1. Because the surround information has been incorporated into the stereo signal with matrix encoding, a Lt/Rt signal can be decoded back into the larger format. Sometimes written Lt-Rt. Compare with Lo/Ro.
LU – Loudness Units. A loudness value measured from the target loudness as used in ITU BS.1770 usually expressed as LKFS or LUFS.
Lucasfilm Ltd., LLC – a movie and television production company founded by George Lucas in 1971 in San Rafael, California. Most of the company's operations were moved to San Francisco in 2005. Lucasfilm was purchased by the Walt Disney Company in 2012.
LUFS – Loudness Units Full Scale. A loudness unit referenced to digital full scale used with the ITU BS.1770 standard for loudness normalization of audio levels used in broadcastTV and other video sources. LUFS is the preferred term used by the EBU, as in EBU R128, while the ATSC prefers the term LKFS, as in ATSC A/85. Although there was originally a sligtht diffenece in the two terms, they are now essentially the same.
lug – an adjustable part of a drum which is threaded and screwed into the ends of the tension rods and used to adjust the tension of the drumhead.
luma – the signal (abbreviated as Y) in a video system that conveys the light intensity (black and white) information of the picture, separately from the color or chroma signal (C). Sometimes incorrectly called luminance, but technically these are different terms. See also YUV.
lumen (lm) – the SI unit used to measure luminous flux. One lux (lx) equals one lumen per square meter. The lumen is related to the candela (cd) as lm = 1 cd × sr, where sr is the number of square radians (or steradians—a unit for measuring solid angles). Since a sphere has a solid angle of 4π sr, a light source that uniformly radiates one candela in all directions has a total luminous flux of 1 cd ×+ 4π or approximately 12.566 lumens. Luminous flux is sometimes expressed in units of power.
luminance – (1) The condition or quality of radiating or reflecting light. (2) A measure of the intensity of a light source or an illuminated surface. Although luminance is often used interchangeably with brightness, these terms are different. Brightness is the way light intensity is perceived by the human eye. (3) Often incorrectly used for the signal in a video system that conveys the picture brightness. The correct term is luma.
luminosity – (1) The relative quantity of light reflected or emitted or the relative brightness of an object. (2) The relative quantity of radiation emitted by a celestial body, such as a star.
luminous flux – the total quantity of visible light emitted by a source, usually expressed in lumens (lm). While radiant flux includes all electromagnetic waves emitted by a source, luminous flux includes only visible light, weighted according to the sensitivity of the human eye at various wavelengths. Also called luminous power.
Note: We believe this is the largest dictionary (glossary) of terms specific to usage within the recording industry that is currently available on the internet, with more than 8,300 entries, nearly 600 illustrations, and dozens of tables. Some of the terms have different or additional meanings in other situations, especially within the electronic, automotive, scientific, and computer industries. Of necessity there are obvious overlaps into other fields such as music, electronics, and computers, but such excursions are limited to information deemed pertinent to the knowledge required to operate and/or participate effectively in the workings of a recording studio. Also included are terms related to sound reinforcement (live performances) including wireless microphone technology because a working knowledge of that terminology is necessary for recording at live performance venues. Because recording studios also record audio for video and motion pictures (films), some terminology from those fields is included. Some scientific terms are included because they help explain studio terminology. For example, electromagnetism explains how microphones, loudspeakers, and guitar pickups work. Knowledge of radio waves and the radio frequency spectrum is needed to explain wireless devices. Any trademarks or trade names mentioned belong to their respective owners. The information contained in this dictionary is believed to be accurate at the time of publication. This information is subject to change without notice. The information was obtained from and cross-checked with a variety of sources that are believed to be reliable. However, Los Senderos Studio, LLC does not guarantee the accuracy or completeness of the information contained herein. Please contact us to report any errors, omissions, discrepancies, or broken links. Los Senderos Studio shall not be responsible for any consequences or damages arising out of the use of this information. Nothing in this glossary should be interpreted as legal advice. For a glossary providing information on legal and business matters for musicians, we suggest you consult Musicians Business Dictionary.
A note on alphabetical order: The terms in this glossary are alphabetical without regard to spaces and punctuation. For example, AM Radio follows amplitude. While this may seem to be at odds with other conventions, it eliminates confusion with words such as pickup, which is sometimes written as pick up or pick-up. In addition, all symbols such as &, -, or / are ignored. The entries on the number page (0-9) are listed in increasing value within each digit. For example, all of the entries beginning with 1 are listed before those starting with 2. For Greek letters (α-ω), the entries are in Greek alphabetical order.