A sonogram, sonograph, or spectrogram is a well-known spectrum display technique in speech research, having been used for decades to analyse utterances. A sonogram shows an overview of the spectrum of several seconds of sound. This enables the viewer to see general features such as the onset of notes or phonemes, formant peaks and major transitions. The sonogram representation has also been employed as an interface for spectrum editing. A sonogram represents a sound as a two-dimensional display of time versus "frequency+amplitude". The vertical depicts frequency (higher frequencies are higher up in the diagram) and shades of gray indicate the amplitude, with dark shades indicating greater intensity. (Source - Curtis Roads (1996). The Computer Music Tutorial. Boston: MIT.)
A sonogram is able to show the relative distribution of sound wave energy within a sound, over time. It can be a useful visual tool for understanding how sounds operate and for identifying the most prominent concentrations of sound wave energy (partials). It can also be very useful in helping to identify and eliminate unwanted portions of a sound, such as noise or fixed pitches caused by electronic equipment.
A sonogram with overlaid waveform
术语顾问/Consultant to terminology