Vol 6 Test 3 Part 4

Section 4
20:29
Part four, you will hear a lecturer in Environmental Science talking about soundscapes, which are the sounds that surround us in our daily lives. First you have some time to look at questions 31 to 40.
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21:20
Now listen carefully and answer questions 31 to 40.
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21:44
Today, I want to talk to you about something called a soundscape. We all know what a landscape is — that is, the view that you can see from any particular point. As the name implies, a soundscape comprises all the sounds you can hear at a given time in a particular environment. The term was first coined by a Canadian called Murray Schaefer, a famous composer who became interested in the concept in the late 1960s and early 1970s.
One important aspect of the soundscape is that it is not random, abstract noise, nor is it simply mindless background sounds, such as the recorded music you hear so often in public places like elevators. No — the sounds in a soundscape generally have meaning and can be understood and decoded.
The sounds of which a soundscape is composed can be divided into three types.
First, biophony.
These are sounds emitted by living creatures — for example, by frogs, which you undoubtedly know can be extremely loud when heard in trees on a dark, wet night. Some people love that sound.
Then the second type of soundscape sound is termed geophony, and that is sound created by non-biological forces. In our daily life, we're constantly surrounded by these sounds — like the patter of rain, which I myself find incredibly soothing and relaxing. Some, of course, would disagree.
Lastly, we have the sounds lumped together under the heading of anthrophony, and these refer to sounds made by humans — an altogether noisy group, I'd say.
Anyhow, the study of the soundscape has attracted many people over the years, including an American called Bernie Krause, who has spent more than 40 years recording the sounds of nature. He came to several interesting conclusions about the sounds he recorded.
He maintained that every sound has what is referred to as its own signature, which makes it as recognizable and identifiable as when a person writes his own name.
Furthermore, Krause concluded that the sounds of various organisms in an environment are harmonious in two ways:
1. they fit together in terms of loudness, so they don’t drown each other out
2. the frequency of each sound is also harmonious with the other sounds
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24:31
Scientists who study soundscapes say that overall changes in the sound patterns in a certain place are often important first indicators of a change that is taking place in the climate of that particular area. This in itself would make a better understanding of soundscapes valuable in trying to assess what is going on in the environment around the world today.
Change in the soundscape may also be a first warning sign of pollution of many kinds. And in fact, it was an absence of birdsong that alerted writer and early ecologist Rachel Carson to the environmental devastation being caused by the understandable attempt by American farmers to control insects.
Soundscape ecologists are using ever more sophisticated equipment to study the sounds of nature, including state-of-the-art acoustic sound recorders. The data from these are used to create three-dimensional maps of acoustic features plotted across a landscape. These can provide a valuable permanent record of the soundscape at a particular time and can be used to note potentially significant changes, such as variation by season.
Now, when I give talks, the most common question that I get asked is: What's the loudest creature in the animal world? The answer is probably debatable, but it's not a roaring lion or a bellowing elephant. To the best of my knowledge, it's something found in the ocean — a shrimp less than four centimeters long, which makes an explosive sound underwater with its single claw, the equivalent of about 160 decibels in air — and that's even more than the noise a rock band makes.
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26:29
That is the end of Part Four. You now have one minute to check your answers to part four.
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27:36
That is the end of the listening test. You now have 10 minutes to transfer your answers to the Listening answer sheet.