Learning Aims:
  • Interpreting the recorded speech waveforms
  • Determining formants of the recorded speech waveforms by using sound signal analysis tools (e.g. Fast Fourier Transform or Liner Prediction)
  • Understanding a spectrogram
A sound sensor, interface and software that displays sound waveforms and allows to perform sound analysis (e.g. CMA Coach 6 or Raven Lite program which also produce Sound spectrogram)
    Suggestions for use:

    In this activity students use a sound sensor to record the human voice sounds. Software for recording and analyzing sound is required. It can be for example:

    By using Signal analysis tools like Fourier Transform or Linear Prediction students can display the frequency spectrum of the recorded sounds and find the frequency components.
    Analyzing a simple sine wave signal produced by a tuning fork is especially illuminating, since frequencies can be calculated in different ways and compared.
    Further students investigate sounds of different vowels and determine the formants of these vowels.

    Possible questions:
    • How could we recognize a vowel from its formants?
    • Which frequencies determine the voice differences between a male and a female ‘aa’-vowel?
    • Which frequencies determine the voice differences between a ‘aa’-vowel and ‘oo’-vowel said in the same pitch.