Now looking at definitions starting with letter "l"
learning curve : In mechanical or electronic systems controlled by computers, the computerís ability to learn the hardware/software, input/output environment-particulars of a situation and use this information to control the systemís statemechanism.
LEDE : Live End Dead End. A commercial trademark used to indicate a particular acoustical design of a recording studio control room. In this design, the area around the monitors is made acoustically absorbent, or dead, while the area behind the listenerís position is made reflective, or live, in an attempt to increase the accuracy of the reproduction. See also ESS, RFZ.
legato : A musical effect whereby the decaytail of one note overlaps the attackhead of the next.
leger line : See stave.
Lemo : A Swiss company which makes high-quality, very dense connectors. Rarely used, Lemo connectors are found on some specialty audio equipment, such as Soundfield microphones (because of the large number of capsules or compact microphones which require a high density of pins in a small space). There is no standard for the pin-outs in Lemo connectors, a fact which contributes to their scarcity.
lento : Italian for "slowly."
Leq : Equivalent sound Level. The Leq of a sonic event is that constant SPL which has the same amount of energy as the actual event. Thus, the Leq is a long-term average, or integration, of an SPL. It is approximately the average of the powers of instantaneous levels taken at equal intervals over time during the measurement period. Leq is a convenient way of accurately measuring the level of a fluctuating sound over a range of a few seconds to several hours.
Leslie cabinet : A type of loudspeaker cabinet, developed by Don Leslie in the 1930ís and used in electronic (especially Hammond) organs. The sound from fixed transducers is dispersed via a rotating horn or (for bass speakers) an aperture in a rotating chute. This causes a continuously varying Doppler shift of the pitches in the audio signal, which mixes, with some phase cancellation, to give a swirling, chorus-like effect.
Leslie simulator : An effects unit which is intended to create the effect produced by a Leslie cabinet. It is similar to a chorus unit, but produces a richer effect.
level : Loosely used when the magnitude of a signal is meant, usually voltage. Strictly speaking, the term should be reserved for the value of a power in dB. The measured level of an audio signal is the amplitude that is caused by the sum of the powers of all of the components of the sound.
level control : An envelope parameter which controls the level of certain synthesizer actions, such as the sustain portion of an ADSR envelope. Compare with rate control.
level scaling : See keyboard scaling.
level-sensing circuit : An electronic circuit that generates a control voltage in proportion to signal level. This control voltage can then be used to affect the amount or type of signal processing done by a separate device. Also called a detector.
leveling : The use of a compressor set to high ratios and very slow attack and release times. With a digital recorder, it may be beneficial to have some kind of leveler followed by a processor that does peak-limiting.
LFE : Low-Frequency Effects. The subwoofer channel signal in a 5.1 surround mix. The equivalent of the subwoofer designation for audio-for-video, where the low-frequency band between about 20 Hz-120Hz is matrixed or channeled for replay. In home audio systems, the subwoofer will frequently contain low frequency information from the main channels in addition to the original LFE track. See also in-band gain.
LFE : Low Frequency Effect (film) or Low Frequency Enhancement (audio). The subwoofer channel signal in a 5.1 surround mix. See in-band gain.
LFO : Low Frequency Oscillator. An oscillator whose output is infrasonic, typically used as a control source for modulating the sound to create vibrato, tremolo, trills, and so on. Unlike a normal oscillator which produces audio signals, an LFO is a generator module that produces a modulation/control signal. The LFOís signal output is in the form of a slow, periodic waveform, usually less than 20 Hz. The most common parameters found in the LFO are depth, frequency (rate control) and waveform selection. See Appendix C.
LFOA : See LFOP.
LFOP : Last Frame of Picture. Film acronym for the length of a given reel of film, usually connoting the head leader up to and including the last frame of the reel. Because it is standard to start counting with the Picture Start from of the leader as 0000+00 (zero feet, zero frames), the actual running time of a reel can be calculated by subtracting 11+15 (eleven feet, fifteen frames) to account for the 12-foot, 8-second leader. The two-pop is at 0009+00, and the first frame of picture of a reel is at 0012+00, sometimes referred to as LFOA.
librarian (software) : Allows for computerized storage and organization of MIDI information for large numbers of synthesized or sampled sounds. Information is organized to be specific to synthesizer manufacturersí protocols. Librarian software sends patch parameter instructions to the synthesizer via a MIDI cable. See editor/librarian.
lift : A section of a longer piece of music which may be edited out and used independently. For example, a musical phrase which is part of a longer piece of commercial music which may be used for use for another purpose than which it was originally written.
lifter : A tape transportís head-lifter mechanism. Tape machines normally lift the tape off the threads when in fast-forward or rewind mode. The synchronizer intelligently controls the machineís lifter operation to read timecode when required.
light metronome : A metronome which silently marks beats by flashing a light on and off, as opposed to audible clicks, to mark the tempo.
light valve : The mechanism which controls the intensity of light or the area on which light falls in the making of an optical track for a film soundtrack from the finished mix. For variable-density tracks, it consists of a narrow slit whose width is varied by the waveform reproduced from the mix, and which in turn modulates the width a beam of light that is focused on a continuously moving strip of photographic film.
Lightpipe A serial, multiplexing, eight-channel interface for digital audio on a single fiber-optic cable, terminating in a proprietary connector. The Lightpipe was invented by Alesis to connect its ADAT MDMs. The data rate is 256 times the sample rate, or four times the data rate of AES/EBU or S/PDIF. See also TDIF.
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