Hearing Frequency and Amplitude

The best way to understand frequency and amplitude is to hear the effect of changing them. We will control a sine wave oscillator, which produces a very smooth tone.

The output of the oscillator will be sent to an on-screen oscilloscope so that we can see the effects visually. The waveform display has time on the horizontal axis and the value of the oscillator output on the vertical axis. It is updated automatically about once per second.

To do:

  • Move the amplitude scrollbar until you hear sound.
  • Move the frequency scrollbar.
  • Listen to the effect of changing the amplitude and frequency. Notice how the waveform changes on the oscilloscope.
  • Try to play a simple tune using the frequency scrollbar.
  • Turn the frequency down until you can’t hear it, at about 10 Hz to 20 Hz. Can you feel your speaker vibrating slowly with your hand? At your own risk, remove the cloth cover from your speaker. Can you see the large woofer vibrating?