THE PSYCHOLOGY OF TONE
SOUND IS THE AUDITORY experience the stimulus for which is the vibratory motion of some elastic body. Whenever such an experience is aroused, the hearer designates the sound as being either a noise or a tone. The first step, therefore, in the psychology of tone is to examine the difference between sound as noise and sound as tone.
If the tones c-e-g-c′-e′-g′-c″ are sounded together, a sound- mass is heard in which the C's stand out. This sound-mass will be called a tone because of the presence in it of one predominant pitch. But in the sound-mass c-d-e-f-g-a-b no one of the constituent sounds is predominant, and the total effect is that of a noise. Tones are thus sounds that have a definite pitch- salient, while noises are sounds without a definite pitch-salient. In other words, a sound to which we are unable to assign a definite pitch--cannot tell whether it is high or low--is a noise. We speak of noises as being sharp, shrill, dull, piercing, soft, harsh, but never as high or low. A few persons often hear tones when most others hear only noises, because their exceptional auditory acuity enables them to detect some one pitch in the mass of sound. Consequently, whether a sound is called a noise or a tone depends as much on who is hearing the sound as it does on the sound itself. For this reason, the only rule that can be laid down regarding the difference between noises and tones is that a sound having pitch is a tone, and a sound without pitch is a noise. Even some sounds produced by musical instruments appear to be more noises than tones. Thus, the lowest tones of the piano or organ, and of other musical instruments having a