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Evolution of the Piano
Figure 6. A square grand piano made in 1793. It has a range of five octaves. From Giordano (2010) with permission from Oxford Uni- versity Press.
struments, and the resulting piano occupies much less floor space than a grand piano. Square grand pianos underwent an evolution similar to that of grand pianos, and by 1850 they had expanded from 5 octaves (as in Figure 6) to 7 oc- taves or more.
These later instruments were about as massive and nearly as big as a grand piano, which was not a good solution for a home instrument. This motivated a different design in which the soundboard lies in a vertical plane—the upright piano. This is a much more efficient use of space, but the upright piano was slow to be adopted because of difficul- ties in designing an efficient action. The actions in tradi- tional grand and square grand pianos propel the hammer upward to its collision with the strings and gravity brings the hammer back to its resting position after the collision. For an upright piano, the strings are aligned vertically, and the hammers move horizontally before and after the colli- sion. Thus, gravity cannot help bring the hammer away after the collision, and an entirely new action design is needed. A satisfactory design for such an action (in which springs and carefully placed straps are used to reset the action after hitting the strings) was not developed until about 1820, and it forms the basis for the action in modern upright pianos. For an animation of the upright piano action, please go to https://www.youtube.com/watch?v=2kikWX2yOto.
After that time, the upright piano became popular and com- pletely displaced square grand pianos after about 1860. For those who are interested in that bit of history, square grand pianos can still be found on ebay (!), but they are not recom- mended for musical use.
Where Will Piano Design Go Next?
The main theme of this article has been the evolution of the piano from the instrument invented by Cristofori to the modern piano of today. There have been substantial changes in nearly all aspects of the instrument, including the strings, string layout, hammers, and case, and these have changed the piano sound in subtle ways. These changes can be heard in the sound files that accompany this article (http://acoustics today.org/the-invention-and-evolution-of-the-piano/) which contain short segments of familiar pieces by Scarlatti and Mozart that are played on both early and modern in- struments. While the tones produced by early and modern pianos certainly can be distinguished, it is evident to most listeners that they come from the “same” instrument. Hence, the “essence” of the piano has been preserved over the three centuries since its invention.
Interestingly, the rate of evolutionary change of the piano slowed greatly in the late 1800s, and a "modern" piano would be very familiar to Johannes Brahms or Theodore Steinway (the patriarch of the famous Steinway family). While there have been small design changes since that time, the piano reached essentially its current form nearly 150 years ago. Why did this evolution stop? We have already seen that the expansion in the number of notes stopped because of limits in the human auditory system. Other factors also contrib- uted, for example, the material used in strings evolved rap- idly between 1750 and 1850 as stronger and stronger forms of iron wire were developed, culminating in the availability of steel wire with a tensile strength not far from today's steel wire. However, such technological considerations don't fully explain why the piano has changed so little in the past cen- tury. For example, advances in material science have given us the possibility of carbon fiber soundboards and strings that might, at least in theory, lead to an improved instru- ment (Giordano, 2011). Such possibilities have not been se- riously explored yet, perhaps because of a general resistance to change among composers, makers, and performers. It is understandably difficult to convince musicians to make sig- nificant changes in an instrument that has been so success- ful. And this is probably not a bad thing.
Acknowledgment
I am grateful to Arthur Popper for his encouragement to put together this paper and for many very helpful suggestions on the manuscript.
18 | Acoustics Today | Spring 2016