When two notes are not quite in unison the resulting sound is found to alternate between a maximum and minimum of loudness recurring periodically.
The pitch of a musical sound depends on the number of cycles passed through by the fluctuations of the pressure per unit of time; the loudness depends on the amount or the amplitude of the fluctuation in each cycle; the quality depends on the form or the nature of the fluctuation in each cycle.
In connexion with the present subject it is important to notice the three characteristics of a musical sound, namely, pitch, loudness and quality.
It consists at times of a low deep moaning, repeated five or six times, ending in faintly audible sighs; at other times he startles the forest with loud, deep-toned, solemn roars, repeated in quick succession, each increasing in loudness to the third or fourth, when his.
An increase in the size of the iron disk attached to the membrane augmented both the loudness and the distinctness of the sounds, and this finally led to the adoption of a thin iron disk supported round its edge, acting as both membrane and armature (fig.
If we are to assume that the tones received by the ear are pure and free from partials, the loudness of the beattones would appear to show that Helmholtz's theory is not a complete account.
The loudness of the sound brought by a train of waves of given wave-length depends on the extent of the to and fro excursion of the air particles.
But the converse, the measurement of the loudness of a sound not produced at our will, is by no means so easy.