Latency
Delay between audio and MIDI

Layering
Sounding two or more voices, each of which typically has its own timbre, from each key depression. Layering can be accomplished within a single synthesizer, or by linking two synths together via MIDI and assigning both to the same MIDI channel.

LFO
Low Frequency Oscillator, used in sound synthesis to modulate a sound attribute such as volume at an audibly slow rate.

Liquid Audio
A widely used but proprietary digital audio system that uses MPEG-2 AAC.

Loop
A piece of material that plays over and over. In a sequencer, a loop repeats a musical phrase. In a sampler, loops are used to allow samples of finite length to be sustained indefinitely.

Lossy compression
A type of data compression that does not keep all information is said to be 'lossy'. Many popular digital audio formats, including MP3, use lossy compression.

low-frequency oscillator (LFO)
An oscillator whose output is below the audible frequency range, typically used as a control source for modulating the sound to create vibrato, tremolo, trills, and so on.

LTC
Short for "Longitudinal Time Code" - Synchronization signal for video links that is recorded to a video tape along with images > VITC)