When Mozart or Haydn needed a new piano, they could not just stroll down to the piano shop in the nearest shopping centre and order one, they would cultivate friendships and perhaps become drinking partners with the many competing craftsman builders of instruments and would thus meet them socially to express their needs. A close liaison would develop in which the aspirations of the artist and the skills of the instrument manufacturer formed an amalgam for a practical solution. The artist thus won the means to enable him to conceive new style compositions in his mind before any piano could produce the sound he wanted. Competition compelled the piano maker to seek out and test new concepts and new materials to provide better sound and performance. In this period the development of piano sound and the durability of pianos improved explosively. This regime persisted through to the days of Liszt whose performances of such huge vigour set the standards for the durability of the modern piano mainly through his association with Steingraeber, and Bosendorfer.
By the end of the nineteenth century, this productive kind of liaison had ceased, and commercial pressures to produce a piano that the masses could afford in their home, forced standardised designs on the profession. These designs have barely changed since the 1880’s. Inevitably, the previous steady emergence of new styles of classical music also stagnated a few decades later. The modern pianist finds himself with no option but to play what is, in truth, a period instrument barely changed since the 1880’s; the novelty of improved piano sound was no longer available.
In due course the established piano builders discarded the redundant craftsmen and innovative engineers in favour of mass production of their existing design concepts. That stagnation persisted until the end of the twentieth century when a few entrepreneurs such as Stuart in Australia dared to innovate in piano design again. To protect their commercial standing, innovation has been strenuously resisted by established builders for some one hundred and fifty years not always by tasteful methods. They obviously, and with good reason, feel threatened.
Since 1880 science has not stagnated in the same way as piano design. New materials, which have been ignored by the big builders and that offer mouth-watering potential in piano design are now widely available and can be cheaply obtained. New powerful computer based engineering design tools offer the innovator extraordinary opportunity to explore and optimise his ideas before building a test instrument.
Regrettably, the highly qualified engineers needed to exploit these opportunities has become a rare breed near extinction. Few, if any real engineers work in the big modern piano manufacturing. Pianos are still designed by ill- substantiated empirical rules developed by mythology since Christofori’s days of the 1720’s. The golden ear of a supposed guru, backed by a misguided arrogance that “their existing designs are so perfect that no improvement is possible” remain the basis by which they attempt to achieve a commercial dominance.
There is one aspect of piano development that has advanced remarkably since the 1880’s and that is cheaper mass production for greater profit. Yamaha and Kawai have led in this achievement and they have thereby made it possible for the public as well as schools and academies to have rugged and adequate instruments of modest musical potential. Their achievement in this quest is rightly creditable, but has not served the profession of classical music well. The move has been taken too far, because piano quality is now being seriously compromised and “cheap” pianos from China have driven builders still trying to produce ultimate quality instruments off the market. Bechstein, Pleyel, Ibach, Bosendorfer, Broadwood, Rönisch, and Feurich, all once great names in piano building, no longer sustain independence of design and manufacture. In some cases they no longer exist at all except as a name usually exploited in Cchina. Now the early signs of similar stress are appearing in piano parts suppliers.
All is not gloom. Entrepreneurs led by Stuart of Australia and, with considerably more cautious innovation, by Fazioli, have recognised an opportunity and seen that pianos can be improved by leaps and bounds. Hurstwood Farm Pianos with their Phoenix and Carbiano instruments have introduced carbon fibre to piano manufacture. Unfortunately in the face of this threat, the complacent big builders of period pianos have reacted by commercial attack rather than meeting the competition by technical improvement. All the modern innovators are being given a hard time because of their historically accumulated financial muscle of the big builders. In the long term, historical experience tells us that innovators who have “got it right” will win as they always do, but the first of them in the field will not necessarily be the one that benefits most.
Innovation and the opportunities
Any innovator must focus clearly on what are his objectives. For the piano, and for the pianist some of the desirable improvements are:-
1. A lighter instrument and preferably one that is small and of low enough weight for him to take his personal piano to his recital, rather than use what most artists encounter, a battered “house piano” that is poorly maintained and inadequate to meet the demands of his playing. Only the top rank artists now have the authority to demand a choice of what piano they play. The venue manager under pressure from the big piano builders, has made it his prerogative to tell most visiting artists what make and model of piano they must use for the performance. No other instrumentalist suffers this indignity. But pianists who step out of line can suffer severe check to their career.
100 years ago, audiences enjoyed the variety of many different makes of fine concert instrument ( Bechstein, Steingraeber, Roenisch, Steinway, Bluthner, Bosendorfer, Challen and Pleyel to mention a few ) but now that pleasure is denied concert goers who must endure the boring monotony of one dominating make. No wonder audiences are diminishing. They have heard it all before.
2. A longer duration of sound from the struck note.
Longer sound opens the door to new compositions with more sonorous melody line. In the early days of short sound pianos, composers by necessity had to repeat the melody note or embellish it with trills and runs, because the sound died too soon. That problem still persists with all traditional build pianos, but Stuart, Paulello and Hurstwood Farm Pianos, each with novel bridge agraffes have shown the way for making big improvements. There is still a long way to go. Others have experimented by electronic energy input to keep the note sounding for longer.
3. More efficient conversion of string vibration energy to sound waves.
The modern traditional piano converts the energy from the pianist to sound with an efficiency of about 4% (comparable with the efficiency of a typical archaic coal burning steam locomotive.) Some of the new pianos have doubled this efficiency by use of bridge agraffes and carbon fibre soundboards. For comparison the production of sound from a wind organ is about 20% efficient and that of a bowed string instrument between 12 and 15 % efficient.
4. More appropriate materials.
The big opportunity is carbon fibre. For soundboards. It is long known that a good soundboard material should have high stiffness and low density. The early piano builders got this right. Spruce is supreme amongst wood and metals in this respect. That is why modern gliders which have the same requirements are made of spruce and not, as some might presume, aluminium. However any engineer knows that carbon fibre has even better properties in this respect. . The art in applying it is to ensure that internal energy loss in the board is minimised and the balance of enhancement of all the harmonics is maintained. A well designed CF board has the same balance of harmonics as a spruce board and the sound of the piano is- or can with appropriate voicing and choice of hammer felt- be the same. There is just more of each harmonic which makes playing easier and hence more accurate and controllable. The type, geometry and orientation of the fibres in a CF soundboard are a critical consideration. Woven fibres may be used for cosmetic reasons on the surface, but internally a different fibre design is needed.
5. Improved Climate resistance.
In any piano made of wood and felt, the dimensions will swell with high humidity and shrink with increased dryness.. Extreme humidity variation will rapidly crack and, destroy a wooden soundboard. In the UK it is very rare to find a soundboard intact on pianos over forty years old because the variation of humidity of the UK climate is too extreme for wooden piano soundboards. Furthermore, small changes of humidity will cause the crown of the board to raise and upset the tuning. Carbon fibre is almost inert to humidity and temperature change and thus is of huge benefit in improving the tuning stability of pianos. However a CF board in a wooden case piano is not the whole panacea because the wood will still change dimension and disrupt the crowning of the board to de tune the piano. A CF soundboard is has the potential to last for the whole life of a piano without splitting or other degradation. Boards lasting 200 years are now thought to be possible. Precaution to protect the board from UV light is however important Hurstwood Farm Phoenix pianos with CF board have a veneer of maple wood or metal over the surface of the board for this purpose.
6. Crown collapse avoidance.
Traditional pianos utilise a change of string angle in the vertical plane across the bridge to develop a contact force between the string and the bridge cap. This causes a down bearing load on the soundboard which is typically of the order of half a ton or more from over 200 strings. Under that continuous load the board crown will inevitably collapse progressively. If the board is thin and flexible the collapse rate will be highest, but a thin board also gives the best acoustic performance. This is a design compromise that cannot be overcome on traditional pianos. Those with the thinnest board may suffer loss of premium performance as little as five years after first build but the more robust designs with thick boards can retain their best performance for up to forty years. (some say at the expense lower sonority level in the upper registers)
Certain, but not all, of the new bridge agraffes enable the essential contact force between string and bridge to be developed without attendant loading of the soundboard. This enables soundboards of previously unthinkable thinness to be used with huge improvement of the acoustic performance. Some piano makers have built and tested CF boards without using such bridge agraffes. They have been compelled to use thick boards for strength reasons. These, for understandable reasons, yield harsh sound. Instead of admitting or recognising their own error they have published criticism of CF soundboards to cover their embarrassment and thereby delayed general adoption of CF for sound boards in the industry.
7. Resonance box and bridge improvement
The resonance box in a piano is that volume between the strings and the lid (open or shut). It is highly beneficial to piano sound that the walls of this zone and the underside of the lid are reflective rather than absorbing of sound waves. Johann Strauss discovered that use of a hard wood such as maple applied to this surface was beneficial. Others have used other hard woods but most mass produced pianos are still built with relatively soft spruce or pine type surfaces.
A piano has been built with granite bridge to enhance acoustic energy transfer- it is said to have been done very successfully. Hurstwood Farm Piano Studios has developed a carbon fibre bridge with the same objective and outcome. Now, granite veneer can be obtained. The first piano with granite veneer lining the resonance box is in planning. All Phoenix pianos have the resonance box veneered with maple.
Since the days of Christofore piano actions have been made of wood. The detail has been refined to the point that in the right climate conditions and under regulation from skilled technicians they perform superbly. But any piano owner will tell you the issues that arise in periods of high humidity are supremely irritating. Uneven touch, sticking notes, dampers that do not drop, slow repetition, and notes where the key depresses but the hammer does not move. All these problems happen due to the wood or felt in the action swelling and causing friction in the various bearings and bushings. Since the introduction of the Kawai and then the WNG carbon fibre /composite actions with precision clearance plastic bushes instead of felt these se difficulties need not affect piano builders. At Hurstwood Farm for amusement a WNG piano action (excluding the hammers) was soaked in a bath of water for 12 hours and then after drip dry put straight back in the pianos which played perfectly.
The Kawai composite action employs wood hammer shanks. WNG use, optionally, stiffer carbon fibre shanks. Concert pianists will be very familiar with the syndrome of sound ceiling on a particular brand of concert pianos when being played fortissimo. The harder they play, the less sound volume is achieved. High speed photography has shown that with fortissimo playing the hammer shank bows upwards with the consequence that the hammer tip that contacts the string moves away from the pianist. There is a sweet spot for correct hammer/string contact and deviation from that reduces sound generation sharply. As well as bowing upwards the shank also performs a twisting vibratory motion which displaces the hammer head sideways so the string at best is contacted by the wrong part of the hammer and at worst it may even miss an outboard string altogether.
It is shames the engineering profession that piano builders who have flexible wood shanks and do not have the competence to engineer change, have spread it around that a flexible shank is beneficial because “it flings the hammer against the string more forcibly”. Such claim has all the validity of a claim to have invented perpetual motion. However they persist with this ludicrous statement and have thereby damaged piano development by retarding the application of stiff CF shanks.
10. 3D printing
A further step change awaits piano action development. That is 3D printing of action parts. Hurstwood Farm Pianos already uses 3 D printing to make action parts for a half blow mechanism in their Phoenix pianos. Huge cost savings are possible by applying this process which is now technically advanced enough for reliable application.
In 2007 Hurstwood Farm decided to take a challenging step forward in piano building by designing a piano almost entirely made of carbon fibre. Indeed it was with this end in mind that carbon fibre soundboards and actions had been marketed in the advanced technology range of Phoenix pianos, but, Phoenix pianos still have a conventional and heavy acoustic body….( acoustic body comprises the frame, the case, the sub frame and the action box. )
This presented a massively big engineering challenge requiring fundamental departure from traditional piano concept.
As temperature changes up or down, the strings correspondingly stretch or contract. In a traditional piano the strings are anchored at both ends to the cast iron frame. By good luck, cast iron stretches and contracts similarly but not exactly the same as steel so the tension in the strings of traditional pianos, and hence the pitch of the note, does not alter substantially with temperature change. A piano with a carbon fibre frame replacing the cast iron frame of a traditional piano would go disastrously flat as temperature rises because carbon fibre barely stretches at all with rise in temperature. This challenge was met in Carbiano by designing a two part frame connected by a device which expends precisely to compensate for the stretch of the strings with temperature. This has proved to be so precise that Carbiano can be cycled through major temperature changes and will hold its pitch far better than any conventional piano.
The next challenge was to design a piano structure of adequate strength to withstand the tension of about 20 tons in the strings. Carbon fibre is stronger and stiffer than steel of a similar weight so this was not fundamentally difficult. However little is known of the ability of CF to contain high stress for long periods. For Carbiano a decision was taken to design the frame so that under load the piano deformation would be the same as that of a conventional piano. The first piano was built that way but initially with time it distorted under load more than a piano with cast iron frame. Tuning stability was unsatisfactory. However with time, as anticipated, the fibres began to take all the load and the resin bonding settled to a situation of minimal load carrying. Now that same piano is very tuning stable.
For commercial pianos it is a simple job to enhance the structure strength at minimal cost in increased weight. The planned production carbianos will be built with 3 times the strength and stiffness of traditional pianos in the upper registers and twice in the lower registers.
Carbon fibre has low strength carrying capacity for sustaining pressure on or in the material. Furthermore drilling into it is not good practice because that will cut the fibres. It follows that a peg such as that used for a hitch pin for the string, like a fencing stake in mud, will lean into the pull of the string. For Carbiano we had to devise and test metal inserts to locate these pins. With reference to practice on F1 cars we found we could bond the metal inserts with glue with a big factor of strength safety. Initially we used stainless steel inserts but despite expansion joints the difference of the quite big temperature expansion of the insert and the negligible expansion of CF caused uncomfortable distortion. We now borrow from the technology of carbon fibre aeroplanes and make the inserts out of a special metal alloy that matches the minimal expansion of CF as temperature rises. Our prototype piano is now four years old, yet no bonded insert has ever loosened under the large continuous loads applied.
Obviously the natural frequencies of Carbiano structure differ much from those of a traditional piano and we had to ensure a proper match of these to the frequency of the notes being played.
We developed a computer programme based on a powerful stressing computation method called finite element analysis. The piano is divided in our case into over six million tiny elements and the action and reaction between these calculated to determine the natural frequency of the whole piano and of all its key parts.
We showed by comparing traditional pianos with this computer system that it was desirable to match the frequency of each struck note with a natural frequency of the piano structure and/ or its elements. This was no problem in the higher registers, because there are many natural frequencies in very close proximity, but in the bass registers the prototype had no natural frequencies below about 40 Hz (c.p.s) whereas the bottom note of the piano is 25Hz. We had in consequence a piano with a very good upper register performance but inadequate bass which was somewhat typical of most baby grands.
Studies were carried out of dimensional changes to:-
a) The soundboard thickness,
b) the bridge height
c) the method of fastening the board in the piano, and
d) The rigidity of the tuning pin block.
e) The ribs and/or elimination of ribs.
This way we succeeded in improving the bass sound to balance the outstanding upper register sound.
There is another major way in which Carbiano differs from traditional pianos. Early pianos had a wood frame. In 1828 builders started to reinforce this with wrought iron and by the mid eighteen hundreds by cast iron frames pioneered by Chickering . Until then the strings and soundboard were still mounted on a sub-base wooden frame and the rim. When full cast frames were introduced the string anchorage was necessarily transferred to the frame, but for inexplicable reasons the soundboard remained mounted on the wooden frame and the rim. This aberration which still persists in piano building illustrates the counter-productive conservatism of the builders in the mid 18thcentury beginning to grip the industry. The soundboard logically, and for acoustic efficiency reasons should be mounted on the cast frame.
Uninhibited by cowardly conservatism, for Carbiano, we took a “bold” step and hung the soundboard from the carbon fibre frame. This enabled us to eliminate the need for a sub-frame and facilitated fitting a second resonance box and soundboard below the main sound board to enhance the sound quality. This resonance box concept was borrowed from loud speaker technology.
It is fascinating to ponder what Christofori would have done had he had CF and computers available to him. One thing is certain he would not have been shackled by the current fear of change that pervades what should be a cultured profession of piano building.
The mindless commercialism of certain practitioners in piano building is tearing the industry apart and risks the total destruction of classical music on which we all depend. For classical music to thrive it must have continuous access to a variety of ever improving instruments on which to conceive new styles of composition.
Richard Dain, Chairman of Phoenix Pianos