by Trevor Cox
55 Bruno Fazenda, personal communication, October 2011.
56 Ibid.
57 P. Devereux, Stone Age Soundtracks: The Acoustic Archaeology of Ancient Sites (London: Vega, 2001), 103.
58 It is possible to get echoes from rings of columns. The Court of 3 Stars at Bicentennial Capitol Mall State Park in Nashville, Tennessee, has fifty 7.6-meter-high (25-foot) limestone columns arranged in two C shapes facing each other. The columns contain bells to play the “Tennessee Waltz” every fifteen minutes. I have been told these columns produce a distinctive echo if you stand in the middle of the circle, and videos on the Internet seem to confirm this claim.
59 Jahn, Devereux, and Ibison, “Acoustical Resonances.”
60 Devereux, Stone Age Soundtracks, 86–89.
61 I became aware of this paper from discussions with Matthew. A lay-language version of his paper is available at http://www.acoustics.org/press/153rd/wright.html, accessed October 25, 2011.
62 Matthew Wright could also have asked whether a burial mound is like a car. Some years ago I was solicited to produce pseudoscience for an advertising campaign proclaiming which model of car was best for singing in. I declined the offer.
3: Barking Fish
1 Loss of food and habitats caused by intensive farming is probably more likely to blame for the loss of songbirds. A study by the British Trust for Ornithology (BTO) found that songbird numbers were no different in places where there were many magpies and places where there were few. S. E. Newson, E. A. Rexstad, S. R. Baillie, S. T. Buckland, and N. J. Aebischer, “Population Changes of Avian Predators and Grey Squirrels in England: Is There Evidence for an Impact on Avian Prey Populations?” Journal of Applied Ecology 47 (2010): 244–52.
2 Chris Watson, personal communication, September 15, 2011.
3 R. S. Ulrich, “View through a Window May Influence Recovery from Surgery,” Science 224 (1984): 420–21. Other studies have shown that nature reduces stress for office workers and prisoners; see G. N. Bratman, J. P. Hamilton, and G. C. Daily, “The Impacts of Nature Experience on Human Cognitive Function and Mental Health,” Annals of the New York Academy of Sciences 1249 (2012): 118–36.
4 The beneficial effect of nature even happens when people are just shown photos rather than experiencing nature firsthand; see “A Walk in the Park a Day Keeps Mental Fatigue Away,” Science News, December 23, 2008, http://www.sciencedaily.com/releases/2008/12/081218122242.htm.
5 R. S. Ulrich, R. F. Simons, B. D. Losito, E. Fiorito, M. A. Miles, and M. Zelson, “Stress Recovery during Exposure to Natural and Urban Environments,” Journal of Environmental Psychology 11 (1991): 201–30.
6 J. J. Alvarsson, S. Wiens, and M. E. Nilsson, “Stress Recovery during Exposure to Nature Sound and Environmental Noise,” International Journal of Environmental Research and Public Health 7 (2010): 1036–46. The study found no effect for heart rate.
7 S. Kaplan and R. Kaplan, The Experience of Nature: A Psychological Perspective (New York: Cambridge University Press, 1989).
8 Myron Nettinga, personal communication, June 24, 2012.
9 H. C. Gerhardt and F. Huber, Acoustic Communication in Insects and Anurans: Common Problems and Diverse Solutions (Chicago: University of Chicago Press, 2002).
10 L. Elliot, A Guide to Wildlife Sounds (Mechanicsburg, PA: Stackpole Books, 2005), 86. For degrees Celsius, divide the number of chirps per minute by 7 and add 4.
11 A drop of an octave is a halving of the frequency. The first note is at about 1,300 hertz, somewhere in the middle of the piccolo’s range.
12 P. C. Nahirney, J. G. Forbes, H. D. Morris, S. C. Chock, and K. Wang, “What the Buzz Was All About: Superfast Song Muscles Rattle the Tymbals of Male Periodical Cicadas,” FASEB Journal 20 (2006): 2017–26.
13 Nettinga, personal communication, June 24, 2012.
14 M. Stroh, “Cicada Song Is Illegally Loud,” Baltimore Sun, May 16, 2004.
15 Ibid.
16 While Micronecta scholtzi is the loudest known aquatic creature relative to its size, comparison with land animals is best avoided. Although the media have claimed that the insect “reached 78.9 decibels, comparable to a passing freight train,” this comparison is incorrect; see T. G. Leighton, “How Can Humans, in Air, Hear Sound Generated Underwater (and Can Goldfish Hear Their Owners Talking)?” Journal of the Acoustical Society of America 131 (2012): 2539–42. The original research published—J. Sueur, D. Mackie, and J. F. C. Windmill, “So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae),” PLoS One 6 (2011): e21089—did not allow for the difference between the density and speed of sound in air versus water.
17 J. Theiss, “Generation and Radiation of Sound by Stridulating Water Insects as Exemplified by the Corixids,” Behavioral Ecology and Sociobiology 10 (1982): 225–35.
18 M. Versluis, B. Schmitz, A. von der Heydt, and D. Lohse, “How Snapping Shrimp Snap: Through Cavitating Bubbles,” Science 289 (2000): 2114–17.
19 Watson, personal communication, September 15, 2011.
20 Ibid.
21 See “Snapping Shrimp Drown Out Sonar with Bubble-Popping Trick, Described in Science,” Science News, September 22, 2000, http://www.sciencedaily.com/releases/2000/09/000922072104.htm.
22 D. Livingstone, Missionary Travels and Researches in South Africa (London: J. Murray, 1857).
23 The actual value measured was 106.7 decibels at a distance of 50 centimeters (about 20 inches), but I have estimated a 1-meter value to be consistent with the rest of the chapter. J. M. Petti, “Loudest,” in University of Florida Book of Insect Records, ed. T. Walker, chap. 24 (Gainesville: University of Florida, 1997), http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_24.shtml.
24 Livingstone, Missionary Travels.
25 Which bit vibrates and radiates can depend on the species. In bullfrogs, tympanic membranes are important; see A. P. Purgue, “Tympanic Sound Radiation in the Bullfrog Rana catesbeiana,” Journal of Comparative Physiology. A, Sensory, Neural, and Behavioral Physiology 181 (1997): 438–45.
26 A. S. Rand and R. Dudley, “Frogs in Helium: The Anuran Vocal Sac Is Not a Cavity Resonator,” Physiological Zoology 66 (1993): 793–806.
27 M. J. Ryan, M. D. Tuttle, and L. K. Taft, “The Costs and Benefits of Frog Chorusing Behavior,” Behavioral Ecology and Sociobiology 8 (1981): 273–78.
28 J. Treasure, “Shh! Sound Health in 8 Steps,” TED Talks, September 2010, http://www.ted.com/talks/julian_treasure_shh_sound_health_in_8_steps.html, accessed September 20, 2012. Musicologist Joseph Jordania suggests that we find humming relaxing because silence is a sign of danger; J. Jordania, “Music and Emotions: Humming in Human Prehistory,” in Problems of Traditional Polyphony. Materials of the Fourth International Symposium on Traditional Polyphony, held at the International Research Centre of Traditional Polyphony at Tbilisi State Conservatory on September 15-19, 2008, ed. R. Tsurtsumia and J. Jordania (Tbilisi, Republic of Georgia: Nova Science, 2010), 41–49.
29 J. Letzing, “A California City Is into Tweeting—Chirping, Actually—in a Big Way,” Wall Street Journal, January 17, 2012.
30 B. Manilow, “Barry’s Response to Australia’s Plan,” the BarryNet, July 18, 2006, http://www.barrynethomepage.com/bmnet000_060718.shtml.
31 The quotes in this section are all taken from Andrew Whitehouse’s research blog, Listening to Birds, http://www.abdn.ac.uk/birdsong/blog, accessed September 2, 2012.
32 Actually, if you compare recordings of a whip and a whipbird side by side, they are quite different. The real whip creates a crack via a sonic boom and does not have a glissando, or the starting tone.
33 The glissando can also go in the opposite direction, from high to low frequency.
34 Daniel Mennill discusses fitness in a paper with Amy Rogers—D. J. Mennill and A. C. Rogers, “Whip It Good! Geographic Consistency in Male Songs and Variability in Female Songs of the Duetting Eastern Whipbird Psophodes olivaceus,” Journal of Avian Biology 37 (2008): 93–100—bu
t in an e-mail to me, Daniel pointed out that the fitness hypothesis is conjecture. By playing recordings of the calls to males and females and watching how the birds responded, Amy Rogers confirmed the duet hypothesis: A. C. Rogers, N. E. Langmore, and R. A. Mulder, “Function of Pair Duets in the Eastern Whipbird: Cooperative Defense or Sexual Conflict?” Behavioral Ecology 18 (2007): 182–88. Duets are probably used for defending territories as well.
35 The decibel levels for the birds come from M. Wahlberg, J. Tougaard, and B. Møhl, “Localising Bitterns Botaurus stellaris with an Array of Non-linked Microphones,” Bioacoustics 13 (2003): 233–45; those for the trumpet, from O. Olsson and D. S. Wahrolén, “Sound Power of Trumpet from Perceived Sound Qualities for Trumpet Players in Practice Rooms” (master’s thesis, Chalmers University of Technology, Sweden, 2010).
36 A. C. Doyle, The Hound of the Baskervilles (Hertfordshire: Wordsworth Editions, 1999), 70.
37 TEDx events are local TED events, conferences designed to spread ideas and change the world. See http://www.ted.com.
38 Most detectors use beats (described in Chapter 8) to adjust sounds so that they’re audible to humans.
39 Allowing for a shift in frequency, this analogy comes from A. van Ryckegham, “How Do Bats Echolocate and How Are They Adapted to This Activity?” December 21, 1998, http://www.scientificamerican.com/article.cfm?id=how-do-bats-echolocate-an.
40 While it can provide some protection, the reflex is not quick enough for sudden sounds such as explosions, and it fatigues if the loud sound lasts too long; see S. Gelfand, Essentials of Audiology, 3rd edition (New York: Thieme, 2009), 44.
41 Chris Watson, speaking on the BBC Radio 4 program The Listeners, broadcast February 28, 2013.
42 R. Simon, M. W. Holderied, C. U. Koch, and O. von Helversen, “Floral Acoustics: Conspicuous Echoes of a Dish-Shaped Leaf Attract Bat Pollinators,” Science 333 (2011): 631–33.
43 Watson, personal communication, September 15, 2011.
44 Ibid.
45 These were probably social calls between dolphins rather than echolocation signals, which are usually at too high a frequency for humans to hear. See, for example, “Bottlenose Dolphins: Communication & Echolocation,” SeaWorld/Busch Gardens Animals, http://www.seaworld.org/animal-info/info-books/bottlenose/communication.htm, accessed September 14, 2012.
46 E. R. Skeate, M. R. Perrow, and J. J. Gilroy, “Likely Effects of Construction of Scroby Sands Offshore Wind Farm on a Mixed Population of Harbour Phoca vitulina and Grey Halichoerus grypus Seals,” Marine Pollution Bulletin 64 (2012): 872–81.
47 E. C. M. Parsons, “Navy Sonar and Cetaceans: Just How Much Does the Gun Need to Smoke Before We Act?” Marine Pollution Bulletin 56 (2008): 1248–57.
48 I first saw this quote in D. C. Finfer, T. G. Leighton, and P. R. White, “Issues Relating to the Use of a 61.5 dB Conversion Factor When Comparing Airborne and Underwater Anthropogenic Noise Levels,” Applied Acoustics 69 (2008): 464–71.
49 Even these conversions are controversial, and some argue that airborne and underwater decibel values should never be compared.
50 I saw the New York Times quote first in T. G. Leighton, “How Can Humans, in Air, Hear Sound Generated Underwater?”. A jet engine typically makes 200 dB re 2 × 10–5 Pa at 1 meter. If the sonar is taken to make 233 dB re 1 × 10–6 Pa at 1 meter underwater, then this might crudely be converted to an airborne equivalent of 233 – 61.5 = 171.5 dB re 2 × 10–5 Pa—actually quieter than one jet engine! See D. M. F. Chapman and D. D. Ellis, “The Elusive Decibel: Thoughts on Sonars and Marine Mammals,” Canadian Acoustics 26 (1998): 29–31.
51 G. V. Frisk, “Noiseonomics: The Relationship between Ambient Noise Levels in the Sea and Global Economic Trends,” Scientific Reports 2 (2012): 437.
52 R. M. Rolland, S. E. Parks, K. E. Hunt, M. Castellote, P. J. Corkeron, D. P. Nowacek, S. K. Wasser, and S. D. Kraus, “Evidence That Ship Noise Increases Stress in Right Whales,” Proceedings of the Royal Society of London. B, Biological Sciences 279 (2012): 2363–68.
53 L. G. Ryan, Insect Musicians & Cricket Champions: A Cultural History of Singing Insects in China and Japan (San Francisco: China Books & Periodicals, 1996), XIII.
54 Watson, personal communication, September 15, 2011.
55 Phil Spector is famous for producing dense pop music in the 1960s from layers of musical instruments often playing in unison. A good example is the hit “Da Doo Ron Ron” by the Crystals.
56 Watson, personal communication, September 15, 2011.
57 E. Nemeth, T. Dabelsteen, S. B. Pedersen, and H. Winkler, “Rainforests as Concert Halls for Birds: Are Reverberations Improving Sound Transmission of Long Song Elements?” Journal of the Acoustical Society of America 119 (2006): 620–26.
58 H. Sakai, S.-I. Sato, and Y. Ando, “Orthogonal Acoustical Factors of Sound Fields in a Forest Compared with Those in a Concert Hall,” Journal of the Acoustical Society of America 104 (1998): 1491–97. In another paper the authors looked at a bamboo forest and found a 1.5-second reverberation time.
59 H. Slabbekoorn, “Singing in the Wild: The Ecology of Birdsong,” in Nature’s Music: The Science of Birdsong, ed. P. Marler and H. Slabbekoorn (Amsterdam: Elsevier, 2004), 198.
60 E. P. Derryberry, “Ecology Shapes Birdsong Evolution: Variation in Morphology and Habitat Explains Variation in White-Crowned Sparrow Song,” American Naturalist 174 (2009): 24–33.
61 H. Slabbekoorn and A. den Boer-Visser, “Cities Change the Song of Birds,” Current Biology 16 (2006): 2326–31. Slabbekoorn and colleagues have also shown that great tits change their songs between quiet and noisy parts of the city, see A Problem with Noise, BBC Radio 4, broadcast August 20, 2009. Also see H. Brumm, “The Impact of Environmental Noise on Song Amplitude in a Territorial Bird,” Journal of Animal Ecology 73 (2004): 434–40; and R. A. Fuller, P. H. Warren, and K. J. Gaston, “Daytime Noise Predicts Nocturnal Singing in Urban Robins,” Biology Letters 3 (2007): 368–70.
62 Hans Slabbekoorn, speaking on the BBC Radio 4 program A Problem with Noise, broadcast August 20, 2009.
63 D. Stover, “Not So Silent Spring,” Conservation Magazine 10 (January–March 2009).
64 D. Kroodsma, “The Diversity and Plasticity of Birdsong,” in Nature’s Music: The Science of Birdsong, ed. P. Marler and H. Slabbekoorn (Amsterdam: Elsevier, 2004), 111.
65 The importance of repertoire to fitness has been shown for other species; see R. I. Bowman, “A Tribute to the Late Luis Felipe Baptista,” in Nature’s Music: The Science of Birdsong, ed. P. Marler and H. Slabbekoorn (Amsterdam: Elsevier, 2004), 15.
66 Ibid., 33.
67 In 1942 the broadcast was aborted when the sounds of Wellington and Lancaster bombers leaving for a raid were picked up by the microphones. A quick-witted engineer had realized that the live broadcast would give an early warning to the Germans. See “The Remarkable Moment the BBC Were Forced to Pull Plug on World War II Birdsong Broadcast as Bombers Flew Overhead,” Daily Mail, January 28, 2012, http://www.dailymail.co.uk/news/article-2093108/The-remarkable-moment-BBC-forced-pull-plug-World-War-II-birdsong-broadcast-bombers-flew-overhead.html.
68 If I were to pen a letter to Andrew Whitehouse, I would write about puffins. These black-and-white seabirds have bright red bills and are called “bird clowns” because they look so comical. They nest underground and chat with their neighbors through the thin earth walls, growling and purring, making sounds like slowed-down sarcastic laughter.
4: Echoes of the Past
1 The first mention of this phrase comes from the Usenet group talk.politics.mideast, January 8, 1993, when the phrase “A duck can quack but his quack never echoes” appears in the signature of a post.
2 R. Plot, The Natural History of Oxford-shire, Being an Essay towards the Natural History of England, 2nd ed. (Oxford: Printed by Leon Lichfield, 1705), 7.
3 Anechoic comes from the Greek an, meaning “without”; and echoic, “relating to an echo.”
4 The cave can still be visited today, and by
all accounts this is an amazing soundscape to visit. A short piece of avian echolocation can be found in P. Mahler and H. Slabbekoorn, eds., Nature’s Music: The Science of Birdsong (Amsterdam: Elsevier, 2004), 275.
5 Encyclopaedia Britannica, “Marin Mersenne,” http://www.britannica.com/EBchecked/topic/376410/Marin-Mersenne, accessed January 5, 2012.
6 A royal foot is an old measurement of distance. I have taken 1 royal foot to be 0.3287 meter.
7 F. V. Hunt, Origins in Acoustics: The Science of Sound from Antiquity to the Age of Newton (New Haven, CT: Yale University Press, 1978), 97. 340 meters per second is the value at 15°C (59°F). The speed of sound depends on temperature.
8 The assumption here is that a quack lasts about 0.19 second and a duck’s foot is 5 centimeters (2 inches) long. This would then be a disyllabic echo, which is the name for an echo consisting of two syllables, according to the old taxonomy.
9 A slightly simplistic calculation, but probably reasonably accurate, unless there is a temperature inversion that allows the quack to carry farther with less attenuation. In many tables, the sound level of a rural setting is shown to be 30 decibels and a whisper, 20 decibels.
10 Hunt, Origins in Acoustics, 96.
11 Yodeling is more than just a kitsch form of entertainment. It probably originated to enable easy communication in the mountains. The characteristic switches from high to low pitch, as the singer switches from falsetto to a more normal singing voice, make it easier to pick out the yodel after it has traveled a long way and is barely audible.
12 J. McConnachie, The Rough Guide to the Loire (London: Rough Guides, 2009), 105.
13 R. Radau, Wonders of Acoustics (New York: Scribner, 1870), 82.
14 M. Riffaterre, Semiotics of Poetry (Bloomington: Indiana University Press, 1978), 20.
15 The structure drawn by Kircher would need panels spaced at something like 267, 445, 657, and 767 meters (290, 485, 720, and 840 yards) from the listener. It would probably be impossible to shout the initial “clamore” loud enough to make the final echo audible, because the panel is too far away. However, by replacing the flat panels drawn by Kircher with concave surfaces, it should be possible to amplify the reflections and overcome this problem.
