CHAPTER XI.THE MECHANISM OF PERCUSSION.The pianoforte hammer is perhaps the most striking of the many and various features of that instrument. Although it is a comparatively simple device, its historical and musical interest is supreme. For while the strings, the framing, and even the action that we see in the instruments of today are but the modern developments of their clavichord and harpsichord ancestors, the hammer, on the contrary, is the one revolutionary device that, at a single step, separated the pianoforte from all other stringed instruments and endowed it with its own peculiar and powerful attributes.It was the hammer, in fact, that made the pianoforte. As soon as it was fitted into a harpsichord, the pianoforte was born, and no refinement of stringing or framing could have effected the fundamental nature of key-board instruments in the same manner. For we must recognize the fact, sometimes overlooked, that the pianoforte is essentially an instrument of percussion. It is necessary that there be a more or less violent blow from the hammer to excite the sound-producing vibrations of the strings. The tone of the instrument, under the most favorable circumstances, cannot fail to partake of the character peculiar to sounds produced in this manner. The importance of the hammer as a tone-producer cannot, then, be underestimated. It stands upon a plane of importance equal to that occupied by the scale-designing, the stringing and the resonance apparatus. We are therefore justified in devoting space to consideration of the construction of this essential feature.We cannot say with absolute surety what was the nature of the material with which the hammers ofCristofori’soriginal invention were covered. But we may presume that it was leather. We know that the hammers were exceedingly small and apparently all of the same size. NeitherSilbermannnorZumpecan be said to have perfected any special improvements in the form of hammer construction,and we find that the revolutionary genius, John Broadwood the First, and alsoSebastian Erard, were the pioneers in the work of adapting the hammers to the more strenuous styles of playing that the improved touch mechanism invented by them permitted and encouraged.Broadwood, who first perceived the necessity of adopting a scientifically correct striking point, likewise began to fit his pianofortes with hammers graduated in size, and under him the leather-covered hammer arrived at its full development.But leather as a covering material soon began to be decried. It was discovered that the kind of tone demanded by the rising pianoforte masters could not be obtained from such material. After much experiment on the part of pianoforte makers, the German-Frenchman, Pape, of Paris, tried the use of felt. His success was immediate and conspicuous, and it was discovered that not only did this kind of covering produce finer tone quality, but there was little difficulty in regulating that quality through the hammers within certain well-defined limits. Nevertheless, we find square pianofortes to-day in which the felt covering upon the higher hammers is overlaid with strips of buckskin. This practice, however, represented the last dying struggles of the leather-covered hammer, and now we use it no longer.It is true that the use of felt is not unattended with conspicuous disadvantages. It wears out rapidly, and unless constantly kept in good condition by use of the felt-needles, the iron, and the sand-paper file, soon comes to produce a harsh and unpleasant tone-quality. This defect arises from the fact that as usually constructed, the continual pounding of the hammer head upon the strings causes the felt on the crown of the hammer head to become tightly packed and compressed, and the shaping of the head to be lost. As will be explained later, this change in the manner in which the head is originally made up causes a modification in the nature of the vibrations set up in the strings, and, as we have already learned, this change in the nature of the produced excitement is the cause of unpleasant tone-quality. Nevertheless, and in spite of these real disadvantages, the use of felt as a covering material for pianoforte hammers is now universal. Nor does it seem at present that we are very likely to find a superior substitute. As we shall shortly see, however, a simple change in the manner of securing the felt to the wooden foundation of the hammer-head may be depended upon to add largely to the durability and efficiency of the whole structure,both as a tone-producing medium and as a mechanical device.As will be surmised by the reader, early covering of pianoforte hammers with felt was a tedious operation. The material was cut up separately for each hammer, and glued on to the wooden head by hand. But this method suffered under the grave disadvantage of affording no correct guide to the true thicknesses and no means other than furnished by hand-cutting, of graduating these thicknesses with exact evenness. It remained for an American (or Americanized German) inventor to devise a machine that should glue up and finish an entire set of hammers from one continuous sheet of felt, of which the thickness was graduated in the making and which could be relied upon to contain the correct amount of felt, of any desired total weight, the whole graduated with great evenness. Not merely was this so, but the methods of manufacturing felt for other special purposes connected with the manufacture of pianofortes has been entirely revolutionized, so that today we have dampers, punchings, and many other parts of the mechanism of pianofortes successfully manufactured out of various kinds of felt, which vary greatly in consistency, thickness, and other properties.To return, however, to the special case of hammer-felt. We find that the original methods of working together the layers of carded wool has been much improved, chiefly through the efforts of the inventor mentioned above. It is now a matter of slight difficulty to turn out sheets of felt for the making of piano hammers that shall have any desired weight, size and graduation of thickness.The weight of the sheets of felt varies largely according to the nature of the hammers that are to be produced. Thus it is customary, as may be guessed, to provide full-size concert grands with hammers of greater thickness, while the smaller styles of instrument have progressively smaller hammers. The actual weights vary according to the caprice or calculation of manufacturers and designers. An average weight of felt for hammers suitable to be placed in a nine-foot concert grand is from 16 to 18 lbs. per sheet. This does not include the “underfelt,” which is glued directly to the wooden head of the hammer and is used to give greater resiliency to the lower hammers. It is generally omitted at the higher treble end.Upright pianofortes frequently are hammered with felt weighing not more than 8 lbs. to the sheet, but this seems to be too light for really efficient results. 10 lbs. is quite light enough in most cases.As has already been indicated, the foundation of the hammer is a wooden molding. Over this is glued, in the machine, a strip of “underfelt,” which is long enough to cover about five and a half or six octaves of hammers, counting from the bass end upwards. The main felting is then laid over this, the thickest end being at the lowest bass. By means of the machines, now so generally used, it is possible to glue the entire underfelt and also the topäfelt, in one piece. The moldings are then separated and the operation is complete. It is customary to insert a small piece of wire, doubled over in a loop, through each hammer, in order to ensure further strength to the fastening.As may well be imagined, the details of manufacture, of the quality of the felting, and of the dimensions of the completed hammers, require much care in their execution. Long practice, study, and experience have combined to render the specialists, who devote themselves to the preparation of hammers and hammer-felt, most excellently fitted to place upon the market the very finest productions of this kind.There have been attempts made at various times to provide a hammer head, and a method of felting it, that would obviate the somewhat rapid deterioration caused by the pounding of the glued and compressed felt against the stiff steel wire strings. The felt, which requires to be compressed before it is glued on to the wooden molding, rapidly becomes altogether too hard. Moreover, the fastening of the felt to the molding is by no means really permanent. It has been suggested that the felt might properly be contained within a wooden shell which would extend as far along the sides of the felt as the wooden molding now reaches within it. The compressed sheet of felt would be forced into this shell and fastened therein so that it would always be protected by an outer wooden covering. Thus, not only would the fastening of the felt to the wood be reduced more secure, but the pounding upon the strings would not so rapidly assure the undue hardening of the felt. For there would not be the hard wooden base between which the strings and the felt is continually subjected to compression. The idea is good and undoubtedly will yet be recognized.Details of the adjustment of the hammers to the rest of the action and of the preparation of them by the tone-regulator, for the better production of good and even tone, will be dealt with in the chapters upon action-and tone-regulating.
The pianoforte hammer is perhaps the most striking of the many and various features of that instrument. Although it is a comparatively simple device, its historical and musical interest is supreme. For while the strings, the framing, and even the action that we see in the instruments of today are but the modern developments of their clavichord and harpsichord ancestors, the hammer, on the contrary, is the one revolutionary device that, at a single step, separated the pianoforte from all other stringed instruments and endowed it with its own peculiar and powerful attributes.
It was the hammer, in fact, that made the pianoforte. As soon as it was fitted into a harpsichord, the pianoforte was born, and no refinement of stringing or framing could have effected the fundamental nature of key-board instruments in the same manner. For we must recognize the fact, sometimes overlooked, that the pianoforte is essentially an instrument of percussion. It is necessary that there be a more or less violent blow from the hammer to excite the sound-producing vibrations of the strings. The tone of the instrument, under the most favorable circumstances, cannot fail to partake of the character peculiar to sounds produced in this manner. The importance of the hammer as a tone-producer cannot, then, be underestimated. It stands upon a plane of importance equal to that occupied by the scale-designing, the stringing and the resonance apparatus. We are therefore justified in devoting space to consideration of the construction of this essential feature.
We cannot say with absolute surety what was the nature of the material with which the hammers ofCristofori’soriginal invention were covered. But we may presume that it was leather. We know that the hammers were exceedingly small and apparently all of the same size. NeitherSilbermannnorZumpecan be said to have perfected any special improvements in the form of hammer construction,and we find that the revolutionary genius, John Broadwood the First, and alsoSebastian Erard, were the pioneers in the work of adapting the hammers to the more strenuous styles of playing that the improved touch mechanism invented by them permitted and encouraged.
Broadwood, who first perceived the necessity of adopting a scientifically correct striking point, likewise began to fit his pianofortes with hammers graduated in size, and under him the leather-covered hammer arrived at its full development.
But leather as a covering material soon began to be decried. It was discovered that the kind of tone demanded by the rising pianoforte masters could not be obtained from such material. After much experiment on the part of pianoforte makers, the German-Frenchman, Pape, of Paris, tried the use of felt. His success was immediate and conspicuous, and it was discovered that not only did this kind of covering produce finer tone quality, but there was little difficulty in regulating that quality through the hammers within certain well-defined limits. Nevertheless, we find square pianofortes to-day in which the felt covering upon the higher hammers is overlaid with strips of buckskin. This practice, however, represented the last dying struggles of the leather-covered hammer, and now we use it no longer.
It is true that the use of felt is not unattended with conspicuous disadvantages. It wears out rapidly, and unless constantly kept in good condition by use of the felt-needles, the iron, and the sand-paper file, soon comes to produce a harsh and unpleasant tone-quality. This defect arises from the fact that as usually constructed, the continual pounding of the hammer head upon the strings causes the felt on the crown of the hammer head to become tightly packed and compressed, and the shaping of the head to be lost. As will be explained later, this change in the manner in which the head is originally made up causes a modification in the nature of the vibrations set up in the strings, and, as we have already learned, this change in the nature of the produced excitement is the cause of unpleasant tone-quality. Nevertheless, and in spite of these real disadvantages, the use of felt as a covering material for pianoforte hammers is now universal. Nor does it seem at present that we are very likely to find a superior substitute. As we shall shortly see, however, a simple change in the manner of securing the felt to the wooden foundation of the hammer-head may be depended upon to add largely to the durability and efficiency of the whole structure,both as a tone-producing medium and as a mechanical device.
As will be surmised by the reader, early covering of pianoforte hammers with felt was a tedious operation. The material was cut up separately for each hammer, and glued on to the wooden head by hand. But this method suffered under the grave disadvantage of affording no correct guide to the true thicknesses and no means other than furnished by hand-cutting, of graduating these thicknesses with exact evenness. It remained for an American (or Americanized German) inventor to devise a machine that should glue up and finish an entire set of hammers from one continuous sheet of felt, of which the thickness was graduated in the making and which could be relied upon to contain the correct amount of felt, of any desired total weight, the whole graduated with great evenness. Not merely was this so, but the methods of manufacturing felt for other special purposes connected with the manufacture of pianofortes has been entirely revolutionized, so that today we have dampers, punchings, and many other parts of the mechanism of pianofortes successfully manufactured out of various kinds of felt, which vary greatly in consistency, thickness, and other properties.
To return, however, to the special case of hammer-felt. We find that the original methods of working together the layers of carded wool has been much improved, chiefly through the efforts of the inventor mentioned above. It is now a matter of slight difficulty to turn out sheets of felt for the making of piano hammers that shall have any desired weight, size and graduation of thickness.
The weight of the sheets of felt varies largely according to the nature of the hammers that are to be produced. Thus it is customary, as may be guessed, to provide full-size concert grands with hammers of greater thickness, while the smaller styles of instrument have progressively smaller hammers. The actual weights vary according to the caprice or calculation of manufacturers and designers. An average weight of felt for hammers suitable to be placed in a nine-foot concert grand is from 16 to 18 lbs. per sheet. This does not include the “underfelt,” which is glued directly to the wooden head of the hammer and is used to give greater resiliency to the lower hammers. It is generally omitted at the higher treble end.
Upright pianofortes frequently are hammered with felt weighing not more than 8 lbs. to the sheet, but this seems to be too light for really efficient results. 10 lbs. is quite light enough in most cases.
As has already been indicated, the foundation of the hammer is a wooden molding. Over this is glued, in the machine, a strip of “underfelt,” which is long enough to cover about five and a half or six octaves of hammers, counting from the bass end upwards. The main felting is then laid over this, the thickest end being at the lowest bass. By means of the machines, now so generally used, it is possible to glue the entire underfelt and also the topäfelt, in one piece. The moldings are then separated and the operation is complete. It is customary to insert a small piece of wire, doubled over in a loop, through each hammer, in order to ensure further strength to the fastening.
As may well be imagined, the details of manufacture, of the quality of the felting, and of the dimensions of the completed hammers, require much care in their execution. Long practice, study, and experience have combined to render the specialists, who devote themselves to the preparation of hammers and hammer-felt, most excellently fitted to place upon the market the very finest productions of this kind.
There have been attempts made at various times to provide a hammer head, and a method of felting it, that would obviate the somewhat rapid deterioration caused by the pounding of the glued and compressed felt against the stiff steel wire strings. The felt, which requires to be compressed before it is glued on to the wooden molding, rapidly becomes altogether too hard. Moreover, the fastening of the felt to the molding is by no means really permanent. It has been suggested that the felt might properly be contained within a wooden shell which would extend as far along the sides of the felt as the wooden molding now reaches within it. The compressed sheet of felt would be forced into this shell and fastened therein so that it would always be protected by an outer wooden covering. Thus, not only would the fastening of the felt to the wood be reduced more secure, but the pounding upon the strings would not so rapidly assure the undue hardening of the felt. For there would not be the hard wooden base between which the strings and the felt is continually subjected to compression. The idea is good and undoubtedly will yet be recognized.
Details of the adjustment of the hammers to the rest of the action and of the preparation of them by the tone-regulator, for the better production of good and even tone, will be dealt with in the chapters upon action-and tone-regulating.