A spectrogram illustrates how the constituent frequencies of a signal vary over time. This application generates the spectrogram of several audio files, including a

• DTMS tone,
• human voice saying “MapleSim”,
• violin note played with vibrato, and an entire violin scale,
• C8 piano note,
• series of dolphin clicks,
• and more.

Interestingly, some electronic musicians hide images in their music; you can only view these images with a spectrogram of the appropriate part of the audio. This includes the track “My Violent Heart” by the Nine Inch Nails; you can view this spectrogram in this application.

The Spectrogram() function was introduced in Maple 18, and also lets you plot the waveform and power spectrum. You can also control the precise color grading, and range of colors used to represent the strength of the frequency contents.