Editing Loudspeaker (section)

===Electromechanical measurements===
Examples of typical [[loudspeaker measurement]] are: amplitude and phase characteristics vs. frequency; impulse response under one or more conditions (e.g. square waves, sine wave bursts, etc.); directivity vs. frequency (e.g. horizontally, vertically, spherically, etc.); [[harmonic distortion|harmonic]] and [[intermodulation distortion]] vs. sound pressure level (SPL) output, using any of several test signals; stored energy (i.e. ringing) at various frequencies; impedance vs. frequency; and small-signal vs. large-signal performance. Most of these measurements require sophisticated and often expensive equipment to perform.{{Citation needed|date=July 2024}} The sound pressure level (SPL) a loudspeaker produces is commonly expressed as [[Sound pressure#Sound pressure level|decibels relative to 20 μPa]] (''dB<sub>SPL</sub>'').