1 Sound wave pressure plot 11

2 Molecular view of sound wave 12

3 Sound propagation when air is cooler near the ground than high above it 14

4 Barbara can hear Alan, but not Clive 14

5 Difiraction 17

6 Difiraction of difierent wavelengths 18

7 The acousto-optic efiect 19

8 Constructive and destructive interference 19

9 Wave shapes 22

10 Standing waves in a pipe open at one end 28

11 Spectrogram 31

Raphael Frey/Wikipedia commons/Creative Commons AttributionShare Alike 3.0 Unported

12 Summing sine waves to approximate a square wave 32

13 Beats 48

Joe Wolfe/〈http://www.animations.physics.unsw.edu.au/jw/beats.htm〉

14 The ear (the middle and inner ears are greatly enlarged) 53

Figure 2a, ‘Mechanism of the Ear’, in Mike Goldsmith, Discord: The Story of Noise (Oxford University Press, 2014), p. 10. By permission of Oxford University Press

15 Frequency dependence of hearing 54

16 Locations of hearing, language, and speech activities in the brain 59

17 Vocal apparatus 65

18 Dynamic microphone 70

19 Condenser microphone 71

20 Loudspeaker 74

21 Ripples vs waves 84

22 Underwater sound velocity proffle 103

Xavier Lurton, An Introduction to Underwater Acoustics: Principles and Applications (Springer Praxis, 2010), p. 40. With permission of Springer Science, Business Media.

23 Active noise cancellation 115