**3.3 How to record a soundscape?**

One of the possible ways to record a soundscape is the soundwalk method. *Soundwalk* method, as a concept, was first introduced by an urban planner Kevin Lynch [20, 21]. His idea was to follow the usual routes which people use on their commute and which are specific to places of interest with the goal of "capturing" their soundscape. The usual recording of a soundscape has the duration of 30 minutes. The 30-minute choice corresponds to the distance a man would walk across in an average European city and, on the other hand, keeps a certain homogeneity as far as activities in that particular soundscape are concerned. Recording takes place several times a day, for several days, however always at a nice and dry weather. Depending on the research premises, the question how to exactly and accurately process the data obtained from the recordings remains. Although most scientists in their studies claim that the *soundwalk* "walks" lasted for an average of 15 minutes, it is possible to record soundscapes for a longer period depending on the focus and goal of the research. It is also possible to "cut" or shorten the longer soundscape recordings and apply other acoustic "tools" to the soundscape recordings.

The *soundwalk* method uses a recorder and a pair of binaural microphones places in the ears of the person who is performing the *soundwalks*, i.e. *soundwalker*. The *soundwalker*, as the name suggests, performs "walks" through a certain environment. The *soundwalker* needs to carefully breath while walking, and this kind of recording is performed normally in dry and sunny weather, unless we want to record a certain natural manifestation, such as rain. Recording is performed at the height of the walker (the binaural microphones are placed in the ears of the walker) and therefore the recorded signals are similar (at the highest possible level) to the signals heard by the pedestrians in that environment (**Figure 11**).

There is still no consensus among scientists regarding the recording length of the soundscape. Namely, there is no clearly defined time limit that would determine the difference between authentically play backed soundscapes while simultaneously avoiding the listener's fatigue. Reproduction of soundscapes in terms of its length depends on the researcher and the purpose of his research from a few minutes to several hours.

#### **3.4 Soundscape analysis**

Alongside the soundwalk method, the researchers usually perform the analysis of the recorded soundscape with the "help" of the questionnaire which is again not defined by any standard or norm. The concept of the questionnaire, whose purpose is a detailed analysis provided by the listener, is not clearly defined, and moreover it depends again on research premises and focus [22–24]. Questionnaires vary from direct questions to listeners about the soundscape, requirements for a more detailed descriptions of the soundscape in terms of defining them as pleasant or unpleasant, attributes that may or may not be related to mathematical scales and adjective pairs that are not standardised so each researcher can use "their own" adjective pairs which they consider to best describe the soundscape and fit their research. An example of questionnaire [25] which uses bipolar adjective pairs is shown in **Table 3**.

**Figure 12** shows an example of performed soundscape analysis, in particular an expressway which stretches from the east to the west exit of the Zagreb, capital of Croatia [26]. To be more precise, **Figure 12** shows a photograph of the recorded location using the *soundwalking* method, the route of the *soundwalker*, the spectrogram of the recording and the sound sources which were characterised as distracting obtained through a specially designed questionnaire for that particular research [26].

To sum it up, the questionnaires are not an objective acoustic parameter; however, they present a good measure of the listener's perception of the soundscape. A major problem is how to correlate such a subjective parameter with objective acoustic parameters, i.e. loudness, sharpness, roughness and fluctuation strength [27].

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the noise barrier.

*Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

**Figure 11.**

**Table 3.**

*An example of the soundwalker's route.*

2 deep - high-pitched 3 diverse - monotonous

 dynamic – calm natural - artificial harmonious - chaotic appealing - repulsive soothing - stressful

11 gentle – rough

*The adjective pairs used in questionnaire [25].*

10 conspicuous – inconspicuous

**3.5 Using the soundscape as a noise reduction instrument**

The ISO 12913-1 standard defines soundscapes as acoustic environments "as perceived by people, in context". Thus, nowadays more and more soundscape studies are oriented towards human health, well-being and overall quality of life [28–31]. In addition, the WHO Environmental Noise Guidelines for the European Region provide certain guidance on protecting human health from harmful exposure to environmental noise. The guidelines strongly recommend reducing the noise levels (Lden and Lnight) for the cases of environmental noise sources such as road traffic noise, railway noise, aircraft noise, wind turbine noise and leisure noise [32]. In the past the only possible approach to resolve this issue and reduce noise levels in an efficient way has been noise barriers which have been described thoroughly in previous sections. However, in order to construct and position an effective noise barrier, first one needs to have enough space for it, i.e. noise barriers can serve as a solutions only if they are planned before the actual building which is today a quite rare case scenario. In addition, if there is an opportunity to incorporate a noise barrier into an existing urban environment, researchers should take into account the "visual pleasantness" as well as the economic feasibility of

**Pair no. Assigned bipolar adjective pair Type of pair** 1 quiet – loud Auditory

4 pleasant - unpleasant Emotional

#### *Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

**Figure 11.**

*Noise and Environment*

several hours.

**3.4 Soundscape analysis**

Lynch [20, 21]. His idea was to follow the usual routes which people use on their commute and which are specific to places of interest with the goal of "capturing" their soundscape. The usual recording of a soundscape has the duration of 30 minutes. The 30-minute choice corresponds to the distance a man would walk across in an average European city and, on the other hand, keeps a certain homogeneity as far as activities in that particular soundscape are concerned. Recording takes place several times a day, for several days, however always at a nice and dry weather. Depending on the research premises, the question how to exactly and accurately process the data obtained from the recordings remains. Although most scientists in their studies claim that the *soundwalk* "walks" lasted for an average of 15 minutes, it is possible to record soundscapes for a longer period depending on the focus and goal of the research. It is also possible to "cut" or shorten the longer soundscape record-

ings and apply other acoustic "tools" to the soundscape recordings.

signals heard by the pedestrians in that environment (**Figure 11**).

The *soundwalk* method uses a recorder and a pair of binaural microphones places in the ears of the person who is performing the *soundwalks*, i.e. *soundwalker*. The *soundwalker*, as the name suggests, performs "walks" through a certain environment. The *soundwalker* needs to carefully breath while walking, and this kind of recording is performed normally in dry and sunny weather, unless we want to record a certain natural manifestation, such as rain. Recording is performed at the height of the walker (the binaural microphones are placed in the ears of the walker) and therefore the recorded signals are similar (at the highest possible level) to the

There is still no consensus among scientists regarding the recording length of the soundscape. Namely, there is no clearly defined time limit that would determine the difference between authentically play backed soundscapes while simultaneously avoiding the listener's fatigue. Reproduction of soundscapes in terms of its length depends on the researcher and the purpose of his research from a few minutes to

Alongside the soundwalk method, the researchers usually perform the analysis of the recorded soundscape with the "help" of the questionnaire which is again not defined by any standard or norm. The concept of the questionnaire, whose purpose is a detailed analysis provided by the listener, is not clearly defined, and moreover it depends again on research premises and focus [22–24]. Questionnaires vary from direct questions to listeners about the soundscape, requirements for a more detailed descriptions of the soundscape in terms of defining them as pleasant or unpleasant, attributes that may or may not be related to mathematical scales and adjective pairs that are not standardised so each researcher can use "their own" adjective pairs which they consider to best describe the soundscape and fit their research. An example of

questionnaire [25] which uses bipolar adjective pairs is shown in **Table 3**.

**Figure 12** shows an example of performed soundscape analysis, in particular an expressway which stretches from the east to the west exit of the Zagreb, capital of Croatia [26]. To be more precise, **Figure 12** shows a photograph of the recorded location using the *soundwalking* method, the route of the *soundwalker*, the spectrogram of the recording and the sound sources which were characterised as distracting obtained through a specially designed questionnaire for that particular

To sum it up, the questionnaires are not an objective acoustic parameter; however, they present a good measure of the listener's perception of the soundscape. A major problem is how to correlate such a subjective parameter with objective acoustic parameters, i.e. loudness, sharpness, roughness and fluctuation strength [27].

**64**

research [26].

*An example of the soundwalker's route.*


#### **Table 3.**

*The adjective pairs used in questionnaire [25].*

### **3.5 Using the soundscape as a noise reduction instrument**

The ISO 12913-1 standard defines soundscapes as acoustic environments "as perceived by people, in context". Thus, nowadays more and more soundscape studies are oriented towards human health, well-being and overall quality of life [28–31]. In addition, the WHO Environmental Noise Guidelines for the European Region provide certain guidance on protecting human health from harmful exposure to environmental noise. The guidelines strongly recommend reducing the noise levels (Lden and Lnight) for the cases of environmental noise sources such as road traffic noise, railway noise, aircraft noise, wind turbine noise and leisure noise [32]. In the past the only possible approach to resolve this issue and reduce noise levels in an efficient way has been noise barriers which have been described thoroughly in previous sections. However, in order to construct and position an effective noise barrier, first one needs to have enough space for it, i.e. noise barriers can serve as a solutions only if they are planned before the actual building which is today a quite rare case scenario. In addition, if there is an opportunity to incorporate a noise barrier into an existing urban environment, researchers should take into account the "visual pleasantness" as well as the economic feasibility of the noise barrier.

**67**

*Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

positive soundscapes [33–36].

for reducing noise pollution.

space offices [38].

Finally the noise barriers as a solution are focused only on reducing the noise levels from traffic sources, while the common and final goal of the WHO and researchers, with different types of expertise, is to improve the overall quality of life by using different tools, guidelines, descriptors and an interdisciplinary approach by designing, preserving and investigating pleasant acoustic environments, i.e.

There are several paths where soundscape research can be used as an instrument

One of them is discovering what in particular makes a certain acoustic environment perceived as pleasant and then utilising those sound sources in negatively perceived soundscapes. Several soundscape studies have shown that the majority of population responds very well to the sound of water and birds singing, and therefore, those sound signals can be used for acoustic masking of unpleasant parts of

When considering negatively perceived indoor soundscape, improvements regarding noise reduction can actually be achieved using specific acoustic absorptive materials and collaborating with architects regarding the layout of, e.g. open-

Another solution can be mixing soundscapes with music. Music is something that is deeply personal, something that consumes us, and it alters our mood. It can lift us up, it can comfort us, and it can make us feel calm and relaxed. Because of that recent studies show good results in creating innovative "music soundscapes" which can be a powerful tool for healing the people from a stressful and overvibrant urban everyday life. To be precise by installing special gazeboes in urban parks and providing the user to combine the preferred music with an existing soundscape, one can create calming and relaxing zones that could provide a short music break from

When considering only noise barriers as an instrument to combat noise and noise pollution, they have the ability to reduce noise levels by 3–20 dB. Over 3000 km of noise barriers have been installed alongside European rail networks. They are even more widely used alongside roads, including countries such as

Austria, Denmark, France, Germany, Italy, Poland, Spain and Netherlands. Keeping that in mind, it can be concluded that noise barriers as a solution are mainly focused on reducing the noise levels from traffic sources, while the goal of the WHO and many researchers is to improve the overall quality of life by using different tools, guidelines, descriptors and an interdisciplinary approach by designing, preserving and investigating positively perceived soundscapes as previously mentioned.

For each noise barrier, its acoustic performance can be determined, as described in Section 2.1. Noise levels reduction with noise barriers. Here are some practical

• First, the results obtained by simulation for five simple 5-m straight noise barriers (made of different materials) are presented. **Figure 13** shows the parameter of average noise reduction (*ILavg*) depending on the receiving position [40].

• In [41] insertion loss values at 1/1 octave band were calculated bearing in mind the noise barrier types, while the height of all noise barrier was fixed at 5 m and the receiver's position was 2 m from the noise barrier. Prediction of sound pressure levels for five types of road traffic noise sources attenuated by

examples regarding the different performance of several noise barriers:

other acoustic environments which may be rated as less pleasant [37].

everyday obligations and help to endure the day in a better mood [39].

**4. Combining the traditional and contemporary approach**

**Figure 12.** *Soundscape analysis.*

#### *Innovative Approaches to Noise Reduction DOI: http://dx.doi.org/10.5772/intechopen.93056*

*Noise and Environment*

**66**

**Figure 12.** *Soundscape analysis.*

Finally the noise barriers as a solution are focused only on reducing the noise levels from traffic sources, while the common and final goal of the WHO and researchers, with different types of expertise, is to improve the overall quality of life by using different tools, guidelines, descriptors and an interdisciplinary approach by designing, preserving and investigating pleasant acoustic environments, i.e. positive soundscapes [33–36].

There are several paths where soundscape research can be used as an instrument for reducing noise pollution.

One of them is discovering what in particular makes a certain acoustic environment perceived as pleasant and then utilising those sound sources in negatively perceived soundscapes. Several soundscape studies have shown that the majority of population responds very well to the sound of water and birds singing, and therefore, those sound signals can be used for acoustic masking of unpleasant parts of other acoustic environments which may be rated as less pleasant [37].

When considering negatively perceived indoor soundscape, improvements regarding noise reduction can actually be achieved using specific acoustic absorptive materials and collaborating with architects regarding the layout of, e.g. openspace offices [38].

Another solution can be mixing soundscapes with music. Music is something that is deeply personal, something that consumes us, and it alters our mood. It can lift us up, it can comfort us, and it can make us feel calm and relaxed. Because of that recent studies show good results in creating innovative "music soundscapes" which can be a powerful tool for healing the people from a stressful and overvibrant urban everyday life. To be precise by installing special gazeboes in urban parks and providing the user to combine the preferred music with an existing soundscape, one can create calming and relaxing zones that could provide a short music break from everyday obligations and help to endure the day in a better mood [39].
