Beats, Waves, Pulsations.—­To obtain absolute accuracy the tuner is guided by beats, waves or pulsations.  These three words refer to one and the same thing, a phenomenon that occurs in certain intervals when two tones are sounded together that are not in exact tune.  These terms must not be confounded with the term “sound wave” or “vibrations” so often used in discussions on the theory of sound.  However, we think the student is thoroughly familiar with these terms.  The rate of vibration of two tones not in a favorable ratio, may produce the phenomenon known as “beats, waves, or pulsations.”  Vibrations may exist either with or without pulsations.

These pulsations are most perceptible in the unison, the octave and the fifth.  They are more easily perceived in the unison than in the octave, and more easily in the octave than in the fifth.  They are also perceptible in the perfect fourth, the major and minor third and some other intervals, but on account of their obscurity, and because these intervals are unnecessary in tuning they have long since been abandoned in “temperament making” (with the exception of the perfect fourth) by most tuners, although a few still make use of it.  We do not say that the fourth is unsafe to tune by, but you will see later on why it is not best to make use of it.

The Fischer System or method of “setting the temperament” has these advantages:  It uses but two kinds of intervals:  the fifth and octave; by employing two whole octaves in place of one or one and a half, nearly all of the middle section of strings is brought up in pitch which insures that the temperament will stand better while the remaining strings are being tuned; and the alternate tuning of the fifth and octave makes the system exceedingly easy to learn, enabling the tuner to work with less mental strain.  Also the two-octave system gives a greater compass for testing, thus insuring greater accuracy.

If you have access to a piano, it will now be well for you to begin training the ear to perceive the pulsations.  If you cannot use a piano, you can train very well by the use of a mandolin, guitar, violin, zither, or any stringed instrument.  An instrument with metal strings, however, is better, as the vibrations are more perfect.

You will, of course, know that the front top panel of the case has to be removed to give access to the tuning pins, and that you should have a regular tuning hammer and set of mutes to begin with.  The panel is held in place in various ways:  sometimes with buttons, sometimes with pins set in slots, and sometimes with patent fastenings; but a little examination will reveal how it may be removed.

To produce a tone of a certain pitch, the string must be of the right thickness and length.  These items are decided by the scale draughtsman in the factory; if incorrect, the tuner can do nothing to improve them.