Methods - Soundscape Ecology: Principles, Patterns, Methods and Applications - page 255

Table 9.3 List of outcomes
useful to appreciate the
quality of a soundscape

Acceptability Identification of place Relaxation
Appropriateness Importance Safety
Clarity Information Satisfaction
Comfort Liveliness Sense of control
Communication Naturalness Solitude
Enjoyment Nature appreciation Tranquility
Excitement Nostalgic attachment Uniqueness
Happiness Peacefulness Variety
Harmony Place attachment Well-being
Source: Adapted with permission from Brown et al. ( 2011 )

Summary
The soundscape analysis at present moment can be distinguished in two main fields:
the measurement of the physical sound (sound pressure and its repartition in a
frequency domain) and a semantic approach that describes how the sound is
perceived by humans and what part culture has in the evaluating process.
Recognizing the difficulty to represent in a synthetic way fields of research that
until now have evolved independently, the different procedures to approach the
sonic phenomenon are summarized as four main actions: automatic recording
procedure; direct aural procedure; direct aural interpretation procedure; and public
interviews procedure.
The sound is a complex phenomenon that copies the environmental context in
which is generated. For this reason many descriptors are requested to approaching
its behavior and its effects on physical and biological objects. frequency, pitch,
period, wavelength, sound speed, wavenumber, amplitude, sound pressure, sound
power, sound intensity, and loudness are some of the distinctive attributes.
The decibel (dB) that represents a ratio between two signals is a very popular
conversion of the sound pressure at a logarithmic scale. The decibel with reference
has at the denominator a value of reference such as like 1 V or 20 Pa.

In modern usage the sounds are converted after the passage in volts by the
microphone transducer into a digital format. To avoid the aliasing effect, the sample
rate, in hertz, of the analog signal must respect the Nyquist frequency, which is half
of the sample rate. The level of accuracy in the analog-to-digital conversion
depends also by the bit depth (2 8 or 2 16 ): the higher the bit depth, the lower is the
quantization noise.
Sound can be represented in terms of frequency domains. The reversible con-
version between the two domains is made generally adopting the Fourier transform
(FT). For a digital signal the adoption of discrete Fourier transform (DFT) can be
implemented by the fast Fourier transform (FFT). To evaluate the variation of
frequency with time, the entire signal is divided into discrete windows (frames), and
to these windows is applied the short-time Fourier transform (STFT).

μ