A Waterfall plot is a three-dimensional plot which shows grid lines for only one of the axes. The result is a series of "mountain" shapes that appear to be side by side, resembling a waterfall. The waterfall plot is often used to show how two-dimensional information changes over time or some other variable. The term "waterfall plot" is sometimes used interchangeably with "spectrogram

Spectrogram

A spectrogram is a time-varying spectral representation that shows how the spectral density of a signal varies with time. Also known as spectral waterfalls, sonograms, voiceprints, or voicegrams, spectrograms are used to identify phonetic sounds, to analyse the cries of animals; they were also...

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Uses

Waterfall plots are often used to show the:

• results of spectrum analysis
  Spectrum analysis
  Spectrum, also known as emission spectrochemical analysis, is the original scientific method of charting and analyzing the chemical properties of matter and gases by looking at the bands in their optical spectrum...
  
  , showing the spectrum of the signal at successive intervals of time.
• delayed response from a loudspeaker
  Loudspeaker
  A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
  
   or listening room produced by impulse response
  Impulse response
  In signal processing, the impulse response, or impulse response function , of a dynamic system is its output when presented with a brief input signal, called an impulse. More generally, an impulse response refers to the reaction of any dynamic system in response to some external change...
  
   testing or MLSSA
  MLSSA
  MLSSA is an acronym for 'maximum length sequence system analyser'. Such analysers have become popular in the testing of loudspeakers and listening rooms for colouration caused by resonance effects....
  
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• spectra at different engine speeds when testing engines.

See also

• Loudspeaker acoustics
  Loudspeaker acoustics
  Loudspeaker acoustics is a subfield of acoustical engineering concerned with the reproduction of sound and the parameters involved in doing so in actual equipment....
  
  
• Loudspeaker measurement
  Loudspeaker measurement
  Loudspeaker measurement is one of the most difficult aspects of audio quality measurement, and also probably the most relevant, since loudspeakers, because they are transducers, have higher distortion than other audio system components....