Audio Terminology And Definitions Dictionary

 

L  Symbol for inductance.

 

Lacquer  The soft disc cut on a lathe from the master tape. It is the first disc stage in the production of LPs. From the lacquer are made a number of negatives and positives before the negative metal stamper can be created to press vinyl discs.

 

LAN  Local Area Network. (See Ethernet.)

 

LCD TV   LCD flat-panel TVs and video projectors use the same basic Liquid Crystal Display technology you'll find in cell phone displays, digital camera and camcorder viewfinders, and computer monitors. LCD panels are composed of two layers of a polarized glass-like material that are bonded to each other. One layer is coated with a polymer holding individual crystals. Electric current that passes through the individual crystals allows the crystals to pass or block light, depending on the information passed from a central controller. LCD crystals do not produce their own light and need a light source shining through the panel (called "backlighting") to produce the image. Newer LCD TVs use LEDs (light emitting diodes) as this light source. The LED arrays are usually located on the edges of the display panel (edge-lighting) or in a layer that covers the rear side of an LCD panel. Although often marketed as "LED TVs," LCD TVs use LCD panels to create the image.

 

LCOS  An abbreviation for Liquid Crystal on Silicon, a type of LCD display technology.

 

LCRS  Abbreviation of left, center, right, surround: the standard channel and speaker configuration for commercial and home theater sound systems. As the name implies, the L speaker is located to the left side of the screen; the C speaker is located at, or close to, the center of the screen; and the R speaker is located to the right side of the screen. The surround (S) channel is reproduced in commercial movie theaters by multiple speakers located above, to the sides, and behind the audience, and in home theaters it is represented by two speakers, usually located above and either behind or to the sides of the listening/viewing area.

 

LFE Channel  (Low-Frequency Effects Channel) This is the ".1"channel in a 5.1, 7.1, or 9.1 home theater system. The LFE channel contains only very low bass information, such as explosions and collisions, and is typically reproduced by a subwoofer.

 

Limiter    A circuit that prevents a signal from exceeding a pre-determined level. A limiter is a distortion prevention device, and limiters are found in many components.

 

Linearity  A general term referring to the accuracy of response of an audio component in terms of a particular measured parameter, such as frequency response. Line Stage: Another name for a preamplifier. A unit that controls the volume and allows for selection of various inputs (CD player, Tuner, etc). 

 

Line Level    The relatively low signal level generated by most audio and audio/video source components, separate processors, etc. Output voltage for "line level" signals is typically in the 0.5 to 5 volt range, depending on the component being measured.

 

Load   Electrical resistance is often referred to as the load.

 

Localization  The ability to detect the origin of a given sound. Localization is a complex process that involves the ear and brain's ability to differentiate between auditory cues. For example, if a subwoofer plays too far up into the upper bass/lower midrange, it becomes easier to localize on its position.

 

Lossless Data Compression  As the name implies, lossless compression retains all of the data of the original file when it's converted to a smaller file size. When a lossless file such as a TIFF file is opened, algorithms restore all the compressed information, creating a duplicate of the original source file. Lossless compression is generally preferred for creating high-quality or professional-grade audio and video files, where it's important to retain fine detail.

 

Lossy Data Compression  This form of compression always discards information in order to conserve space and reduce file size. When files are decompressed, the missing information is reconstructed through algorithms, usually resulting in some loss of sound quality or image detail when compared to the original. Generally, the higher the resolution of the compressing file, the less the degradation. An MP3 file with a resolution of 256 Kbps, for example, tends to sound more like the source file than one made at 64 Kbps.

 

Loudspeaker  A device for converting electrical energy into acoustic energy. (and see Speaker.

 

Low-Pass Filter   The functional opposite of a high-pass filter, low-pass filters progressively attenuate signals above a pre-determined frequency while "passing" lower frequency signal components. (See also: high-pass filter).

 

LP  Long Playing record. Usually a 12 inch diameter vinyl disc. 

 

LW   Long Wave band (one of three AM radio bands, the other two being Short Wave and Medium Wave).