Spectrograms

Spectrograms are pictures of speech: in spy movies they are often called ‘voiceprints’, which although inaccurate conveys the idea that it shows a picture of someone speaking.

Spectrograms provide more complex information than waveforms. Time, as in waveforms, is marked on the x-axis. The y-axis shows frequency. Amplitude is reflected in darkness: the louder a given component in the speech signal is, the darker it appears on the spectrogram.