Sound Boards

A review of patents issued to the Steinways through April 4, 1885, when the last patent taken out by Theodor Steinway was issued, indicates that the following main changes to sound boards that were: Moving the sound board bridge to the center of the board, use of screws acting on the edges of the sound board to control the tension of the board, adding hardwood strips to the ribs attached to the sound board, adding sustaining bars to prevent warping, and changing the support of the sound board to use of gluing around all its edges to the bent rim and a transverse frame. This last change, covered by patents issued in 1880 and 1885, indicates that the use of screws around the edges of the sound board was discontinued. All of the changes discussed above were directed at increasing the volume and quality of the sound.

A review of the technical literature regarding sound boards in Steinway pianos has the following interesting information:

* The report of the jury for the 1867 Paris exposition has the following discussion regarding use of screws to adjust the tension in sounding boards of Steinway pianos: “The success of this arrangement, with respect to beauty of sound and solidity of accord, induced the Messrs Steinway to apply the same system to the construction of grand pianos, whose power of sound became more melodious and more sympathetic by means of this compression of the board at will. The Messrs. Steinway took out a patent, June 5, 1866, for this important improvement.” (1, p. 311)

* A Steinway brochure in the 1877 Lakeside Directory has the following information regarding sound boards:

o “A construction of the sound board, with its system of compression (as shown in the patents of 1866, 1869, and 1872), preventing that relaxation of the sound-board which is the natural result of its constant concussion, caused by the strokes of the hammers against the strings, and by atmospheric influences.” (2, p. 1145)

o All three styles of Upright Pianos have our Patent Resonator, a simple apparatus, compressing the sound-board, which, while isolating it from the Iron Frame, regulates the tension of the sounding-board with the greatest nicety, giving full play to its increased vibration, and placing it forever under control. (2, p. 1168)

o Patent New Iron Cupola and Pier Frame for Self-Compression, applied to Grand and Upright Pianos. The flat form in the iron frame is here replaced by the cupola shape, its outer edges being curved toward the sound board, thereby possessing far greater strength of resisting the strain of the strings and augmenting the free vibrations of the sound-board. (2, p. 1171)

* An 1884 article in the Sunday Magazine has the following note regarding many design features introduced by Steinway & Sons that revolutionized piano design, including how sounding boards were activated: “This successful result was first achieved by the firm of Steinway & Sons, of New York, who in 1855, constructed a piano with a solid front bar and full iron frame, the latter covering the wrest-plank, the wrest-plank bridge, however, being made of wood. The brace which in the treble connected the “hitch-pin plate” with the wrest-plank plate, was slightly elevated above the strings, and ran in a different direction to the latter, namely, exactly to the angle at which the wrest-plank had to sustain the pull of the strings. The bridges of the sounding-board were grouped in such a manner, that they were moved considerably nearer to the middle of the latter, and at the same time the lineal length of these bridges was increased by placing the bass strings of the instrument over the others - or overstringing them - over three nearly parallel bridges, thus increasing the length of the latter over the sounding-board, viz: from forty to sixty eight inches, their position being removed from the iron covered edges of the case nearer to the centre of the sounding board. The results achieved by this novel construction were in every way most successful. The first instrument made on this plan received, by a unanimous verdict of the jury, the first prize, a gold medal, at the exhibition of the American Institute at the Crystal Palace in New York, in 1855. This new method of construction very soon became the standard for all manufacturers in that and other cities, and, as far as can be ascertained, all square pianos manufactured in the United States at the present time are to a greater or less extent, constructed in with this system.” (3, p. 514)

* The 1890 book by Spillane has the following comment regarding sound boards in Steinway pianos: “Patent No. 55,385, dated June 5th, 1866, granted to William Steinway, who is also a practical inventor, for a "resonator" based upon an ingenious system of regulating the tension of sounding-boards, which is a noteworthy study in piano acoustics.” (4, pp. 218-19)

* The 1892 book by Fanny Morris Smith has a chapter on sound boards and also long sections on the science and technology developed by Theodor Steinway. (Reference 5) Her book notes that Steinway made many improvements of the design of sound boards and accompanying parts of the piano that increased the volume and quality of the sound. These improvements included (1) moving the sound board bridge to the center of the sound board, (2) use of a continuous curved sound board bridge that improved the ability of all the strings to cause the sound board to vibrate, (3) selection of the wood and fabrication of sound board bridges to increase their ability to transmit vibrations over the full size of the board, (4) designing the details of the piano to ensure that vibrations of the wooden parts do not cause vibration of the metal parts, and (5) use of a continuous bent rim made using layered veneers of selected types of wood to conduct vibrations to all parts of the sound board.

In summary, sound boards form the heart of pianos and are designed and manufactured with great care. As described in two books regarding Steinway pianos, References 6 and 7, sound boards in Steinway pianos are carefully fabricated from selected Sitka spruce boards, and are then carefully glued into the rim and transverse support of the piano. Some important steps in the design evolution of sound boards in Steinway pianos are described in the patents and technical literature discussed above.
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For an image of a sound board click on: https://pdfpiw.uspto.gov/.piw?Docid=00204110&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0204,110.PN.%2526OS%3DPN%2F0204,110%2526RS%3DPN%2F0204,110&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

Sources:

1. M. Fetis, “Official Report of the Jury Upon Musical Instruments of the Paris Exposition of 1867,” Source: Watson's Art Journal, Vol. 8, No. 24 (APRIL 4, 1868), pp. 309-312. Available at https://www.jstor.org/stable/44629889.
2. Hutchinson, Thomas, Compiler, The Lakeside Annual Directory of the City of Chicago Embracing a Complete and General Directory, Chicago: Donnelly, Loyd and Company, 1877-1878, Available at: https://books.google.com/books?id=oUo9AQAAMAAJ
3. "The Pianoforte, Ancient and Modern," pp. 509-15. Frank Leslie’s Sunday Magazine, Volume XV, January – June 1884, T. DeWitt Talmage, Ed.
4. Spillane, D., History of the American Pianoforte; Its Technical Development and the Trade, New York: D. Spillane Publisher, 1890.
5. Smith, Fanny Morris, A Noble Art, Three Lectures on the Evolution and Construction of the Piano, New York: De Vinne Press, 1892.
6. Miles Chapin and Rodica Prato, 88 Keys, the Making of a Steinway Piano, New York: Clarkson Potter/Publishers, 1997.
7. James Barron, The Making of a Steinway Concert Grand Piano,” New York: Times Books,2006.