L

Level
Ten times the logarithm of the ratio of a quantity to a reference quantity of the same type. The unit of this logarithmic quantity is decibels (dB). Sound pressure level, sound intensity level and sound power level are three most commonly used levels in architectural acoustics.

Live End/Dead End (LEDE)
An acoustical treatment plan for rooms in which one end is highly absorbent and the other end is reflective and diffusive.

Loudness
The subjective response of the human hearing mechanism to changing sound pressure.