Basic Physical and Psychoacoustical Processes, Lathom-Radocy and Radocy

Lathom-Radocy and Radocy here provide an excellent, clear and accessible overview of physical and psychoacoustical processes, with an emphasis on the topics of greatest importance to musicians and music researchers. Beginning with the subheading “vibration,” the authors clearly define and discuss relationships between frequency, Hertz, amplitude, and overtones, amongst others.

The follow this by discussing the travel of sound waves, which by nature requires a physical medium. An analogy of a line of dominos toppling over, one after the next, more clearly explains the travel of a sound wave – the wave consists of physical energy transmitted from one particle in the air to the next – rather than a ball flying through the air analogy, where the actual ‘substance’ of the subject moves through space. Explaining the difference between transverse waves and longitudinal ones, they clarify why music is primarily (though not exclusively) concerned with longitudinal waves. The important properties of traveling waves are explored: speed, frequency and wavelength. Interference, reflection, refraction and diffraction. Standing waves are given a slight explanation (these are considered quite important in the Italian-Swedish school of vocal pedagogy, incidently).

After discussing sound and the waves in which it travels, the authors turn their attention to the auditory environment, discussing such topics as reverberation time (citing that generally 1 to 1.7 seconds is considered satisfactory) and sound distribution. They claim that “even [sound] distribution is encouraged by rough, irregular surfaces and a lack of an overly symmetrical shape” (p. 75), which is interesting and also stands in contrast to the design of many concert halls – especially older ones.

Next, the authors turn their attention to psychoacoustical phenomena. This primarily deals with how humans respond to physical stimuli. After cautioning that presenting a “dualistic” viewpoint is not always seen as completely accurate (and giving examples of why later), the authors proceed to describe various psychoacoustical aspects and their roughly-corresponding physical aspects. They relate frequency to pitch, intensity to loudness, and waveform to timbre. A fair amount of detail on each of these psychoacoustical phenomena is presented in a precise, if concise, manner.

Personally, I learned quite a bit from reading this. My thinking was not yet so clear and to distinguish precisely between physical- and psyco-acoustical phenomena. This article is an excellent step in clarifying that, and also an excellent step toward understanding music perception and hearing more accurately.