A piano originally built with a high-tension scale, such as a larger concert grand, presents a wider range of options. For example, because many pianists love the clarity and extended sustain characteristic of the concert grand's low bass, more of these instruments are now being found in private homes. But the percussive power of the concert grand is so overwhelming in a small space that it can mask a great deal of musical subtlety. With appropriate redesign, the acoustical palette can be matched to the smaller space. The bass retains that wonderful, long-string clarity and sustain, but the whole instrument becomes more balanced and controllable.
Another option with redesign is to adapt the tonal palette to better suit a particular musical style. Many pianists find the percussive power of even the more lightly-strung modern pianos inappropriate for works by the early classical composers. For these players, the piano's design can be altered to give a more subtle and delicate voice, to emulate the sound of the pianoforte of the mid-19th century. The action can be given a lighter, quicker touch and feel, while retaining the reliability and consistency of a modern action.
Achieving acoustical balance is a common goal of the value-added rebuilder. Most of the stringing scales found on vintage pianos — and more than a few new ones — are very uneven. New stringing scales that meet the new acoustical goals set for the instrument are designed, and new bridges are built to suit. Particular care is taken to blend the piano's voice across the bass-to-tenor transition; by its nature this transition should be imperceptible to the musician and should not require extensive hammer voicing to mask any inherent shortcomings of the fundamental design.
It's critical that the vibrating characteristics of the soundboard match the character of the stringing scale. Until the 1970s, the design and function of the modern piano's soundboard was shrouded in mythology. But over the past 35 years, the hundreds of hours and thousands of dollars invested in study and experimental work have given rebuilders a whole new set of design tools to work with that allow them to accurately predict the acoustical performance of a new soundboard design. The effects of soundboard thickness, grain orientation, and ribs are understood, so rather than simply duplicating the original soundboard — which may or may not have worked all that well — new soundboards can now be designed and built to work predictably in synergy with the stringing scale. Ribs are usually crowned to a precise radius, and are cut to a calculated thickness and height to carry a known string-downbearing load. Rib locations can be moved to better distribute the vibrating energy of the strings, and to control unwanted resonances and give the piano a smoother voice. Soundboard shaping devices such as cutoff bars are used to reduce the size of the soundboard and make the system more efficient.
Today's rebuilder also has a wide selection of actions from which to choose. These range from simply replacing the wippens and hammershanks with new wood components from Renner or Tokiwa, to fitting a completely new composite action stack made by Wessel, Nickel & Gross. The range of options for tailoring action characteristics to suit the individual performer has never been greater.
With the proper balance between the stringing scale and the soundboard system, hammer selection becomes relatively easy. The value-added rebuilder will have a good understanding of the physical characteristics of the aftermarket hammers available — and today the choices are excellent — and will know which hammers will best suit the particular piano he or she is working on. Ideally, the hammers will require a minimal amount of voicing. Indeed, excessive hammer voicing is always an indication that something is out of balance: either the stringing scale and the soundboard system are not well matched, or the wrong replacement hammers have been selected.
Rebuilding a piano in this fashion costs very little more than conventional rebuilding, and supplies the pianist, amateur or professional, with an instrument specifically tailored to his or her personal taste, and that will provide a supremely satisfying musical experience.
Delwin D. Fandrich, RPT, is a piano designer, rebuilder, and former R&D director of the Baldwin Piano & Organ Co. Much of the basic research leading to the development of value-added rebuilding has been conducted in Mr. Fandrich's workshops. He has designed and built many unique pianos, including the Fandrich U-122, for which he holds the patent on the soundboard's Impedance Bar (Z-bar) technology. Mr. Fandrich published the updated version of Piano Tone Building in 2006, and teaches piano technology worldwide. He can be reached at firstname.lastname@example.org or email@example.com.