Electronic device that measures a particular spectrum or frequency band and displays information about that particular spectrum or band. An audio spectrum analyzer is commonly used to measure the frequency response of a given audio system in a given room. It can be used to help adjust the location of speakers by determining where the flattest frequency response is. It can also be used to set an equalizer in order to obtain a flatter frequency response. erforming set-up tasks, audio spectrum analyzers are used with test tones, usually pink noise. The analyzer features a microphone that is placed at the primary listening position (the sweet spot). Audio signals affect the microphone and transmit the signal to the analyzer, which in term plots the signal on a graph showing where it is goes above and falls below a zero point flat frequency response. Spectrum analyzers are fairly expensive and thus are used primarily for professional set-up of an audio system in particular when an equalizer is being installed.