Scan 65
Musical Courier 1892-12-21: Vol 25 Iss 668, 1892
24 lines. Read by computer on 23 September 2026. Printed page 58. See the scan on archive.org.
1Helmholtz, is one of the most beautiful applications of science to art that our civilization has seen.
3Piano makers agree that the point at which the hammer strikes the string greatly affects the tone, but they differ in practice. They hold that if the hammer attacks a nodal point all the partial tones belonging to that node disappear, because the node, or point of rest, is thereby set in motion; but if the hammer attacks the centre of an internode it strengthens its vibrations. For example, if the centre of the string is struck, the second partial, the octave of the fundamental which has its node at that point, disappears, and also all other octaves of this partial, for that point is a node for them all; but the third partial, whose nodes divide the string into three equal parts, is strengthened, because one of its vibrating segments is excited by the blow. This statement works well in practice; but Mr. Hipkins, at the request of Mr. Alexander Ellis, translator of Helmholtz, undertook a series of investigations which proved conclusively that, though much weakened, the partial belonging to the node attacked was not totally eliminated.
5The point at which the damper comes in contact with the string is also decided by the nodes. But good damping depends even more upon the quality of the damper felt. The farther the hammer is moved toward the centre of the string the greater the number of partial tones which are efaced and the more hollow the timbre; but the nearer its attack is brought to the end of the string the greater the number of partial tones which it permits to form and the more piercing the tone becomes. I remember seeing a man show a poor violin on the same principle. He slipped his bow well toward the finger board, and so cut off all the dissonant partials which would have formed if he had played near the bridge. The problem is to select (and provide a construction which will permit) that striking point which eliminates the dissonant partials and retains those which are consonant.
7Some American piano makers allow almost no partials on their strings. The resulting tone is very much like that of a tuning fork, tolerably loud, but not at all sweet. Other makers place their striking point near the end of the string, consequently their pianos when a little worn give a harsh, "tin-panny" tone, caused by the presence of a number of dissonant partials. These partials do not appear in a perfectly new piano, because the hammer is then comparatively soft. The usual striking point is at one-eighth or one-ninth of the string length, even less in the extreme treble. This matter is so important that there is an arrangement in Steinway pianos by which the entire mechanism of keys and action can be moved forward and back in the treble. The proper striking point of the hammers on the string is thus secured with perfect exactness.
9The size, weight and covering of the hammer affect the tone in the most peremptory manner. An old maker once told me that the whole secret of piano building was in the hammer. It is the subject of constant change and experiment in every progressive manufactory. If the hammer be too large or too soft it damps off the string; if too light, the volume of tone diminishes. If it be too hard, or ill regulated, so as to jerk the string, it produces an angular form of vibration, representing numerous dissonant partial tones, which manifest themselves more and more as the hammer grows still harder with use. The hammer must not only be well made, but must suit the scale and build of its piano. I once heard a Chickering grand which had been fitted with a set of large, soft Steinway hammers. It sounded as if it had a cold in its head.
11We have seen, in the oblique position of the bass hammers, that the angle at which they attack the string alters the form of vibration—therefore the quality of the tone. The length of time the hammer is in contact with the string, depending on the action, also affects the tone. According to Helmholtz, this should be just long enough to allow the consonant partials to form, and to eliminate those which are dissonant. Partials whose period of vibration is nearly twice the length of time during which the hammer is touching the string are specially favored; those whose periodic time is six, ten or fourteen times as great are suppressed. The softness or hardness of the hammer conditions this result.
13The art of hammer making involves the elasticity of the head. Formerly several layers of skin were glued together by hand to make a hammer. America and France each claim as their discovery the substitution of felt for leather. At present the cutting and bending of the hammer felt is done by machinery. The elasticity of the hammer is produced by the strain on the outer surface as it is brought into rounded form over the inner. Its hardness or softness varies according to the desire of the maker to favor the production of partial tones in his instruments, or to suppress them. No other part of the action wears out so soon; even comparative durability is therefore of the first consequence. Hammers are sometimes made of one layer of felt, sometimes of two, or even more; the outer softer than the inner, both for durability and for mechanical reasons. It requires a constant and enormous pressure to bend the felt around the hammer shank, with the rib of the felt inside.
15Among the great makers of piano felt are Alfred Dolge of America, and Weikert of Europe, who have spent their lives in perfecting the mixture of hair and wool which gives its durability and its velvet tone to a good hammer. It is the inner part which effects the greater elastic rebound; but the tremendous compression of the outer rim of the hammer gives great elasticity throughout. Neither the striking point of the hammer on the string, nor the duration of its contact with the string, nor the size and weight of the hammers among themselves, is uniform throughout the scale in any good piano. Different makers diverge widely in their individual practice. It is the art of the piano maker so to vary the hammers as to compensate for, or qualify the length, thickness and tension of the strings which they excite. The longest time of contact is a fraction of a second, and the variations are in minute fractions of a second. Upon the security of position and the accuracy of the motion of the hammers in their frame depends the equality of the tone, no less than the durability of the action. Cheap pianos fail here most conspicuously. In the old system of securing the hammer butts on wooden frames even the most careful preparation and choice of the wooden bars could not prevent their warping and swelling under climatic influence.
17The actions in Steinway pianos lie upon a metal frame, whose hollow tubes are filled with hard wood, forced in under great pressure. Into these tubes the screw holes for the trains of actions are accurately bored. But the great expense of the expedient prevents its adoption in cheap pianos. Hammer making, like the manufacture of piano glue, is a business by itself; but first-class piano makers make their own hammers. I have here a Steinway hammer, somewhat worn, a French hammer, and also the set belonging to my antique. The tiny, light, shapeless implement of the eighteenth century contrasts strongly with the large modern hammer from the Steinway grand piano. The hammer which is taken from the corresponding octave of a French action is smaller and lighter than the Steinway, and thus betrays at once the thinner string and slighter tension of the foreign instrument to which it belongs. The Steinway hammer is said to be heavy, and relatively so it is, but it is extremely light and elastic when its size is considered. The groove worn by the string acted, when in use, as a slight damper. If the hammer had been too thin and too hard the same amount of wear would have cut near enough to the wood to produce an exceedingly harsh tone. You see the Scylla and Charybdis of piano makers.
19THE ACTION.
21The modern varieties of the action—that is, the mechanism which conveys the stroke of the pianist's finger to the hammer—were in a more or less complete form in the hands of manufacturers as early as the first quarter of our century. (Erard had patented his repetition action, the present favorite in America, as early as 1821.) All were to be greatly altered and improved by the application of the scientific principles belonging to leverage, striking energy and friction. The touch is the most salient feature of the action. You see the key to be a lever; pressed by the finger, it raises the various carriers, hoppers, jacks and pilots involved in the attack of the hammer. I have illustrated several primitive specimens of actions in a previous lecture; the English direct, whose hopper is pivoted on the key, or on a second lever raised by the key; the Viennese, whose key carries the hammer itself.
23The cut shows the repetition action of the Steinway grand, which is the Erard improved. The brilliancy and
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