Topics for today:

  • Quiz on reading and lecture material.
  • Harmonics and complicated periodic vibrations
    • Periodic waveforms have harmonic spectra: signal energy is discrete at frequencies that are integer multiples of the fundamental frequency, known as harmonics, overtones, or harmonic partials.
    • The distribution of energy among the harmonics gives rise to audible changes in the perceived sound quality, or timbre. For example, different sung vowels at the same pitch are recognizable as “ahh,” “ohhh,” “eeee”, and so forth.
  • Audible examples of various effects; experiment to measure the speed of sound, etc.

Topics for the next lecture:

  • Reading assignment: Chapters 6 and 8 from the Strong textbook.
  • Wave interference; sound level (decibel).