Some tuners favor the term, "laying the bearings," others say "setting the temperament." The former is more commonplace, as it merely suggests the idea of laying a number of patterns by which all others are to be measured. The latter term is extremely comprehensive. A lucid definition of the word "temperament," in the sense in which it is used here, would require a discourse of considerable length. The following statements will elicit the full meaning of the term:
The untutored would, perhaps, not think of setting a temperament to tune by. He would likely begin at some unfavorable point, and tune by various intervals, relying wholly upon his conception of pitch for the accuracy of the tones tuned, the same as a violinist in tuning his four strings. To be sure, pitch has to be reckoned as a rude guide in setting the tones; but if pitch alone were the guide we would never attain to any degree of perfection in scale forming. We could never adjust our tones to that delicate fineness so much appreciated, which gives to the instrument its surpassing brilliancy.
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.
To produce the correct pitch, the string must be of the right tension, which is brought about by winding one end of the string around the tuning pin until the proper degree of tension is reached. This must be decided by the ear of the tuner. Two strings of equal thickness and equal length produce the same tone when brought to the same tension; the result being known as "unison." A defect in the unison being the easiest way in which to detect the beats, we advise that the student practice on it first.
After taking out the panel, the first thing to do is to place your rubber mute between two trios of strings (if the piano is an upright which usually has three strings to a note) so that only two strings sound when the key is struck. Select some key near the middle of the keyboard. Strike the key strongly and hold it down. If the two sounding strings give forth a smooth, unwavering tonea tone that sounds as if it came from one string, the unison is perfect. If you find it so, remove the mute and place it on the other side of the trio of strings. If the piano has been tuned recently by an expert, you may have to continue your search over several keys before you find an imperfect unison; but you will rarely find a piano in such perfect tune that it will not contain some defective unisons. However, if you do not succeed in finding a defective unison, select a key near the middle of the key-board, place your mute so that but two strings sound, and with your tuning hammer loosen one of the strings very slightly. Now you will notice a throbbing, beating sound, very unlike the tone produced when the strings were in exact unison. See if you can count the beats. If you have lowered the tension too much, the beats will be too rapid to permit counting. Now with a steady and gradual pull, with the heel of the hand against some stationary part, bring the string up slowly. You will notice these waves become slower and slower. When they become quite slow, stop and count, or wave the hand in time with the pulsations. After practicing this until you are sure your ear has become accustomed to the beats and will recognize them again, you may proceed to perfect the unison. Bring the string up gradually as before, and when the unison is reached you will hear one single, simple, musical tone, as though it were from a single string. Never have more than two strings sounding at once. You might go over the entire key-board now and correct all the unisons if the scale is yet fairly good. See which string is, in your opinion, the nearest to correctness with respect to the scale, and tune the other one, or two, as the case may be, to it. If the scale is badly out of symmetry, you will not get very good results without setting a temperament; but the tones will sound better individually. This experiment is more for practice than for improving the piano.