Long description

This is a screenshot from Interactive 4 showing the same graphs as Figure 30, but this time a ‘noise’ wave has been added. This is shown in the frequency domain as a vertical line at 935 hertz that is between the first two lines (110 and 330 hertz) in height. On the left, the wave has been disrupted from its almost square appearance and now has lots of large high-frequency peaks and troughs. This time when the loudspeaker button is pressed, the high-frequency ‘noise’ is heard as background to the harmonious square wave.