Physiological acoustics is concerned with the two distinct but related fields of hearing and phonation, and thus overlaps in part with the medical specialties of audiology and otolaryngology. Physiological acoustics differs from these medical specialties in that it does not deal with disease, trauma, and other pathological phenomena, and it limits anatomical study to what is necessary from a functional standpoint.
From the auditory side, physiological acoustics studies the subjective quantities characteristic of hearing (pitch, sound sensation, differential thresholds of frequency and intensity) in relation to the corresponding objective quantities of external stimulation (frequency, global sound pressure and its spectral distribution).
It is also interested in all the characteristic phenomena of hearing (e.g. masking, auditory fatigue, directional effect, adaptation, monaural and binaural beats, and other temporal phenomena), also with the aim of incorporating all these phenomena into a satisfactory theory of hearing.
On the side of phonation, physiological acoustics constitutes that part of phonetics which includes: the study of the mechanism of vocal emission, from the mechanical, acoustic and nervous sides; the study of the objective characteristics of the human voice (analysis of the voice and its temporal evolution, i.e. the determination of its instantaneous spectral composition); and the study of those devices suitable for the synthesis and recognition of the human voice. The last two areas constitute experimental phonetics.