Laser Diode - A semiconductor device that emits a laser beam.

LCD - Liquid Crystal Display. A type of digital display made of a material that changes reflectance or transmittance when an electrical field is applied to it.

Le - (Measured in Millihenries, mH) The electrical inductance of a speaker's voice coil. As frequencies rise or drop there will be a slight fluctuation in impedance because the voice coil is acting as an inductor.

LED - Light Emitting Diode.

Limiter - An electronic compressor with a fixed ratio of 10:1 or greater used to prevent an audio signal from becoming any larger than the threshold setting. Used primarily for prevent and reduce clipping distortion.

Line Level - The standard preamplifier output level of a signal from an audio source. Usually between 100mV and 1V, but may be as high as 5V or more from some indash units. Higher line level output allows the user to turn down the gain (input sensitivity) of their amps to improve the signal to noise ratio.

Linear (Voice Coil) - The ability of the voice coil to move in and out in the air gap without moving side-to-side. Non-linear movement can damage the voice coil.

Linear (Audio Device) - The ability to pass a signal without distorting or altering the waveform image in any way (within the device's specified operating range).

Listening Position Control - A feature which can optimize frequency response and imaging for a particular position in a vehicle. Usually done through the use of signal delay to adjust arrival time of each speaker's output.

Load - The resistance or impedance to which energy is being supplied. In the case of amplifiers, speakers connected to the output of the amplifier are the load.

Local / Distance Switch - Reduces image rejection for weaker, distant stations to increase the chance of receiving a signal.

Loss - The difference between potential energy output and actual energy output. Also can refer to the difference between all the content of an input signal and the actual output signal.

Loudness Control - Intended to boost low frequencies at lower volume levels to compensate for reduced level of bass frequencies that we perceive at low volume levels. The contour of this is usually based on the Fletcher-Munson Curve table.This should not be used at high volume listening levels because higher levels of distortion (clipping) may occur increasing the chance of equipment damage.

Loudspeaker - An electro-acoustic transducer that converts electrical audio signals at its input to audible sound waves at its output. May also refer a complete speaker system/cabinet.

Low Frequency (Bass) - In audio it usually refers to frequencies in the 20-160 Hz band.

Low Frequency (Radio) - Refers to radio frequencies within the 30-300 kHz band.

Low Frequency Driver - A speaker with typically a larger cone, magnet structure, and voice coil. Specifically designed to reproduce long, low-frequency wave lengths. Also called a Woofer.

Low Pass Filter - A network of components which pass frequencies below a predetermined frequency. Frequencies above the cut-off are attenuated out. For diagrams of low pass passive crossover filters, see Passive Crossover Networks.

L-Pad - A potentiometer (variable rotating switch) used primarily to attenuate an amp's output being delivered to a speaker. Generally used as a remote site volume control.

Low Q - A low Q (reactance) woofer is desirable for use in a vented enclosure. Also referred to as Low QTS.