PURPOSE: To produce audio spectrograms in the classroom.

DESCRIPTION: This demonstration uses FFT software to produce sound spectrograms of the voice as well as any other sound source that can be input to the computer sound board using a 1/8 inch connector.

Shown above is a male voice singing a series of vowel sounds, shown at the top of the picture, at a frequency of about 100 Hz; click on the picture to see and hear how this type of spectrogram is created. At the end of the video each section of the spectrum is labeled by its vowel sound, and the first and second formant regions are numbered, illustrating the movement of the two formants that produces the various vowel sounds.

Below are the spectrograms of pouring water into a cylindrical tube (left/top) and Shepard's tones (right/bottom).

Ask for any sources that you wish to use with this demonstration.

SUGGESTIONS: You should practice before using this one in class.

REFERENCES: (PIRA unknown) See equipment file for manual describing this apparatus and its operation.

EQUIPMENT: Computer with sound spectrogram software, small amplifier for microphone and high level signals, microphone, connecting cables, and any other sound source desired.

SETUP TIME: 5 min.