According to JIS Z 8106 Acoustic Terminology, sound is defined as "a sound wave or the auditory sensation caused by it," indicating that sound has both aspects: as a physical phenomenon and as a sensory experience.
Generally, the term is used to describe sounds in a sensory sense, such as good sounds, bad sounds, loud sounds, or high-pitched sounds. Sounds are said to have three attributes, as shown in Figure 1, based on their meaning and significance, and the results they produce.
JIS Z 8106 Musical Terminology
Definition of sound: Sound waves or the auditory sensations they produce.
-
Figure 1: Attributes of sound
In terms of the "social aspects" of sound, noise pollution is a negative issue. Traffic noise (road traffic, railways, aircraft), a prime example of noise pollution, saw dramatic reductions in noise levels over the 30-40 years since the 1960s and 70s, when noise problems intensified, due to measures taken at each source. However, it has been reported that people's harsh perceptions of noise have hardly softened in proportion to these changes. Similarly, in apartment buildings, where noise is a common problem, while high-airtightness and high-sound-insulation housing has become more common recently, and measures to block external noise have improved considerably, noise complaints remain one of the most frequent complaints after moving in. Against this backdrop, recent noise problems are shifting towards a balanced approach. As I will discuss in a later installment, measures against prominent noise sources (emission) have largely subsided, and recent academic conferences are discussing the need for a comprehensive approach that includes the transmission path of noise, the environment in which noise is received (inmission), and the relationship with other noises present in that environment (masking).
Similarly, in the realm of "cultural aspects," music and communication through language immediately come to mind as positive aspects. The realm of sound creation in interior spaces and industrial products would also fall into this category. Recently, even with car engine sounds, the focus has shifted from simply pursuing quietness as noise to creating comfortable sounds that are appropriate to the concept. In home appliances, such as vacuum cleaners, progress has been made in "quietness," but a new approach called "pleasant sound design" is also being explored, which aims to give value to the sounds that objects produce.
In the "informational nature" category, sound is somewhat more neutral than the other two frameworks, and it includes cases where sound is used to convey information about events to people, including attracting attention. For example, directly, this includes clock bells and car horns. Indirectly, it includes sounds generated from the mechanisms of industrial products. For example, washing machines and dishwashers produce various sounds during a certain operating time. In addition to direct notification sounds (signals such as completion), there is also the aspect that the operating status can be understood through sound.
Donald A. Norman states the following in his recent book, "Designing the Future of Things":
"If everything were soundproofed, cushioned, and disinfected, we would no longer notice real dangers. Technological advancements keep people away from certain risks, which in turn leads to new risks."
I've strayed a bit from the main topic, but it seems that future approaches to handling machine noise won't be solely focused on noise reduction.
Another important aspect of sound's "informational value" is its ability to signal abnormalities. When an unusual sound is heard, it provides information that may indicate a malfunction.
Sound has many facets, and its evaluation as noise varies greatly from person to person (sometimes even to the opposite degree). Even sounds that fall under cultural or informational attributes may be perceived as negative noise by some. In the future, sound will likely play a significant role in improving quality of life (QOL) in both manufacturing and environmental design. Towards the grand goal of creating a comfortable sound environment, sound professionals will need a multifaceted approach that considers not only the physical aspects but also the auditory sensations caused by sound waves.
We'll address the subjective aspect of sound at a later time, and in the next installment, I'd like to begin by discussing the fundamental properties of physical sound that we measure.
Well then, I look forward to seeing you next time.
(Excerpt from the email newsletter issued on April 23, 2009)
