Volume 1
A text-book of experimental psychology : with laboratory exercises / by Charles S. Myers.
- Charles Samuel Myers
- Date:
- 1911
Licence: Public Domain Mark
Credit: A text-book of experimental psychology : with laboratory exercises / by Charles S. Myers. Source: Wellcome Collection.
48/370 page 28
![the tonic are major. Minor intervals appear only in the minor scales. Let us for the moment restrict our attention to the major scale, and let us proceed to construct another major scale, making d the tonic in place of c, and calculating the vibration numbers of the tones that lie a major second, a major third, a fourth, a fifth, a major sixth, and a major seventh above the tonic. Then we shall find that only two of these six tones are already represented in the scale of c. When further we similarly calculate the tones of the major scales of e, f g, a, and b, we find that altogether eleven additional tones are required within the octave. So, too, in order to play the minor intervals it will be found that eight additional tones are required. Now in order to reduce the enormous number of notes which would thus be needful for us to play major and minor scales from all possible tonics, a system of equal temperament has been employed in tuning the pianoforte and similar instruments. The tones between each octave are divided into twelve equidistant semitones, the result of which is that the only exactly intoned interval is the octave. All the other intervals in such tempered instruments are more or less, but so slightly, out of tune, that we can start a scale on any tonic we please. In other words, we can play a melody in any key we like.] The Relation of Overtones to Timbre.— Hitherto we have spoken of pendular vibrations of sound waves and of the corresponding pure tone sensations as if they had real existence. We have now to qualify this notion very materially. There is no known source of sound that produces a pure tone sensation. If an instrument be sounded so as to produce a tone, say of 500 vibrations per second, we cannot avoid the simultaneous production of other tones which, in many cases, are simple multiples of that tone. We speak of the tone 500 as the ‘primary’ or ‘fundamental’ tone. The tones which accompany it, having vibration frequencies of 1000, 1500, 2000, etc., are called ‘harmonics’ or harmonic ‘overtones.’ The number and loudness of these various overtones vary in different instruments and affect the ‘colour’ or timbre of the](https://iiif.wellcomecollection.org/image/b3135984x_0001_0048.jp2/full/800%2C/0/default.jpg)
