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Carbon Fibre in Piano Building
Article published on 12 January, 2008

Carbon Fibre in Piano Building - and Other Forthcoming Piano Design Improvements

Whither the British Classical Piano?

Improving the efficiency of conversion of finger energy to sound

In May 2002 (Issue 12) Ingenia published a technical paper on improvements in design of acoustic classical pianos.  The objective of the research described was to improve the efficiency of conversion of finger energy to sound energy by improved energy transfer from the strings to the soundboard using what we called a bridge agraffe..  That efficiency was shown to be doubled    from 4% to 8% , a still abysmally low figure and a giant leap, but the improvement was not uniform across the whole register.


The extra sound came as a greatly increased sustain of the note with high sound intensity and higher initial sound energy at first strike.


 Zero Down bearing opens  way for new technology

As all research progresses new problems are encountered and new ideas abound to achieve even more.  This piano was no exception.  The concept of our Bridge Agraffe opened a very special opportunity for change.  In traditional pianos the string is held against the bridge cap by a change of angle of the string in two planes across the bridge.  In the vertical plane this causes a very large down bearing clamping load on the bridge cap and hence the soundboard..  Without that load the string would not stay in contact with the bridge and little sound would be produced.  In consequence  the soundboard must be designed both as an acoustic member and as a strength member.  The bridge agraffe concept uses the tension in the string to develop the contact force between string and bridge cap without resultant down bearing load.  The soundboard can be designed solely in its acoustic role. The contact pressure can be set to almost any level required.  We find a value of around 8 times that used in traditional pianos is most effective.

The angle changes are responsible for causing some of the loss of clarity and purity of sound in traditional pianos.  The new agraffe permits a straight line of string between its anchor points.   This promotes steady vibration of the string in the vertical plane of movement that  is initiated by the hammer strike.  That mode of vibration creates the clearest, purist sound.


How we set about our task

At this stage we decided to take advantage of the potential offered and found ourselves trying to enter the mind set of the early inventors of piano technology  namely Christofori  and  his development successors Chickering of America who first applied cast frames in pianos and Erard who pioneered the modern piano action. 

What would these genius designers have done had they access to modern science and materials?


Carbon Fibre Soundboards and appropriate hammers

The ideal material for a piano soundboard is well understood to be one that has a high ratio of coefficient of elasticity to density.  Carbon fibre stands out as supreme in this property.  Many others had seen the potential of this but had been compromised by the need to make the board strong as well as a good acoustic device.  Simple calculation showed that a board about 4mm thick would provide the necessary strength  to support the down bearing load of the strings of over a half tonne.  None who tried could achieve acceptable sound with such a board and all abandoned the work.

When improved vibration energy transfer from string to soundboard is achieved it is the upper partials which benefit most.  Most partials above the seventh harmonic are discordant, and the existence of disproportionate energy in the upper partials causes a shrill bright sound.  We encountered this with our early bridge agraffes and incorporated a harmonic filter in the device to control the enhancement of these partials so we were ready when something similar happened with carbon fibre soundboards.  The partials can also be modified by voicing…softening  hammers so they damp the upper partials while they contact the strings on first impact.  It is a fact that as we improve the efficiency of energy transfer to the soundboard we progressively have to resort to softer and different shaped hammers to control the sound quality at each intervention. Soft hammers need higher grade more elastic wool fibre to ensure durability. 


We currently use 2mm thick soundboards in carbon fibre that have a variety of different gauges and orientation of the fibres to ensure rapid and equal distribution of sound energy throughout the soundboard.


That we have been successful is evidenced by the remarks about a recording by Eric Himy of Schumann by two of the top critics in the business:-

“We are told this is the first recording of the new Steingraeber-Phoenix Pianos.  The sound is of extraordinary richness but also of refinement .”

Tanner  BBC Music Magazine


“This new recording is likely to be the best sounding piano disc you have yet purchased.  Recorded on the new Steingraeber-Phoenix piano the sound is weighty and convincing.”

Dave Holmes  Audio Emporium (USA)


Climate resistance

In the UK few piano sound boards survive more than a few years because of extremes of humidity caused by central heating.  In other parts of the World the climate makes maintenance of pianos virtually impossible.


A beneficial consequence of using carbon fibre for the soundboard is that it is climate resistant and has no joints that might fracture..


A new Fibre composite action

While this work was going on we have been assessing a new fibre composite piano action developed by Wessel Nickel and Gross.  Our first piano fitted with this action is now complete.   The outcome exceeds our highest expectations. The original specification had wool bushing cloth bearings.  We arranged for this to be changed to solid bushings because wool in a composite is not able to breathe out excess moisture and is subject to swelling and sticking of bearings.  When the first modified action arrived we immersed part of it in a tank of water overnight.  The following morning we blew it dry and found it functioned perfectly immediately.  A placebo wooden action was seized solid with similar treatment.


This new action is presently an optional feature only.  We are arranging for a professional artist to pass opinion because as an amateur pianist I cannot trust myself to be sensitive enough to the demands of advanced performance.  Finding an artist who will comment at all let alone positively is not easy.  Almost all the top performers are contracted to a major builder never to play or comment positively about any other make of piano or they suffer loss of benefit and other retribution that may be exacted, such as arriving on stage to find the piano being wheeled off.  Yes, it really was done by Steinway to Garrick Ohlsson in 1971 after he said “Bosendorfer was the Rolls Royce of Pianos” !. ( See Article in New York Times by Michael Wise .)


The Recession Demands a new piano when it is over.  How do we know when  we are ready?

The financial recession is placing on our Company a responsibility to be ready with a new product when  recovery occurs.  It is always difficult for an innovator to recognise when his idea is sufficiently developed to permit commercial introduction.  For ever he can  see new exciting ideas  that tempt a delay while they are implemented.  We have ideas for an all carbon fibre piano, a carbon fibre bridge, a climate resistant keyboard and many other fascinating concepts.  Some of these are well advanced in testing. 


We have taken a decision to introduce innovation in two steps.  Initially we  will  offer a piano with bridge agraffes, plus options for carbon fibre soundboard , fibre composite action  and  extra dampers to cover for the longer sustain in the upper registers and hydraulically operated combined and sequenced una corda and half blow pedal to facilitate  quiet playing and sound colour change in pianissimo passages.  If possible we will add the climate resistant keyboard to this specification in due course but no more.  Pianos with 102 notes can be built to special order.


The all Carbon Fibre Piano

In the second phase which may be 2 to 3 years ahead we will finish our “all carbon fibre” piano for which we have already instructed building a prototype.  That will be a 102 key piano.  Extra keys are not a new idea.  The Bosendorfer Imperial has 97 keys including a bottom C at 16 Hz which enables organ music to be played.  If all the extra keys are added at the bottom register the asymmetry of the keyboard often causes serious  disorientation of the artist.  That is one important reason one  rarely sees an Imperial on the concert stage.  Stuart builds a 97 key piano with additional notes both at top and bottom.  Most artists who play this piano do not even notice the register extension.  The last increase in register was introduced at the end of the nineteenth century from 85 to 88 notes. Any musician studying classical music will soon realise that great composers such as Liszt, Brahms  and Rachmaninoff  yearned for these extra bass notes and had to circumscribe their scores to allow for their absence.     Debussy  whose personal piano was an Imperial wrote music that envisaged their availability.  The extra notes at the top of the piano are of little musical use but they do impart an extra flexibilty to the soundboard that enhances the sound of the useful register at that point.  We are satisfied that a piano only very marginally wider than standard instruments can accommodate these extra notes.


Carbon Fibre Bridge

Another feature of innovative pianos will be a carbon fibre bridge.  The best bridges are now made of laminates of veneer of ebony maple and beech with the fibres lying vertically.  This is the orientation that best transfers sound energy from the bridge cap to the  soundboard.. Small pianos benefit from a fairly flexible bridge  but larger instruments demand a stiffer bridge that helps support the  unfortunately mandatory down bearing load on the larger traditional soundboards .  The use of a carbon fibre composite laminate offers the opportunity to control both acoustic energy transfer and stiffness. Though with zero down-bearing the latter feature is superfluous.


Each time we take a step towards more efficient  energy conversion from finger energy to acoustic energy we need to improve high partial filtration to retain the sound quality.  Our ultimate aim is to make a piano with about 15 to 18% conversion efficiency thus matching that of the best wind instruments.


Artist/ Instrument Interface

Perhaps the most critical feature of any quality piano design is the so called   “artist / instrument interface”.  This feature defines how comfortable and confident the artist feels at the keyboard..  Theodore Steinway took this feature to new heights when he brought out his “Centennial” design to celebrate the 100 years since the American War of Independence. (1876)   That design concept is little changed in modern Steinway, but the lead they once had is diminishing.

Many top artists have played our Steingraeber-Phoenix pianos.  Virtually all comment on its excellent artist/instrument interface and add they put it down to a supposed innovation in the action design geometry.  No such innovation exists.  We have therefore attempted to define what they are sensing.  We now believe it to be a matter of how much sound volume is obtained from a given finger energy input.  If the artist puts less energy through the action there is less friction and it feels smoother.  If he has to do less finger work to achieve the sound level he wants then he has to make less effort and hence has better control for high speed repetition and accuracy. Sustain of the notes also plays a part.


Carbon Fibre hammer Shanks

When we use a fibre composite action we also use tubular carbon fibre hammer shanks of reduced diameter  (4.5mm instead of 6.3 mm.)  The hollow shanks do not sound a sympathetic and discordant note as do solid carbon fibre shanks yet they clearly improve the efficiency of transfer of energy from finger to string. These are another link in the chain of the move to higher conversion efficiency of input energy to sound energy.


Climate Resistant keyboard

The concept of a climate resistant keyboard for which we already have a working test rig  substitutes fibre composite parts  and sold bushings for conventional  wool or leather bushings.  The design we have conceived also offers screw adjustment of the height of the key at the balance rail so very precise key levelling is possible and easy without recourse to felt or paper washers under the key.


The Technical Challenge

The all carbon fibre piano presents some huge challenges. Not least is the almost zero coefficient of thermal expansion of carbon fibre which would cause a piano with CF frame and steel strings to lose pitch catastrophically  when it warmed up only a few degrees C.  We started the work by laser scanning a traditional piano so we had precise dimensions and a FE stress analysis of all the components.  This work was extended so we could display the resonances and movements of all parts of the piano as each key was struck.  We learned much from this work.  Most surprising were


a) the keyboard at times has rolling displacement waves across its registers   

b) the massive wooden carcass beams forming the sub-frame under a piano, (a relic of the days before cast iron frames) wobble around like jelly at certain input frequencies.

c) the rim of the piano acts as an extension of the sound board and radiates sound energy wastefully and randomly instead of retaining it where it belongs in the resonance box.

d) the massive thick cast frame at certain places  and frequencies waves ‘like a flag in a breeze’


The stress levels show the sub-frame carcass beams serve little purpose except to be a location for the wood soundboard and to retain its dome shape..  (Chickering missed a trick when he introduced the full cast frame.  He could have attached the soundboard to that frame and eliminated the sub-frame altogether.)  That is what we are doing.  Our soundboard will be attached directly to the carbon fibre frame.. 


Carbon fibre has negligible coefficient of thermal expansion.  It follows that with change of temperature a carbon fibre piano strung with steel strings will drop sharply in pitch as temperature rises.  We have devised a method of compensation for this.  There are boron glass reinforced composites of higher coefficient of thermal expansion but not of equal or adequate strength or stiffness to be used in a piano frame.


Carbon fibre loses strength when machined or drilled because the fibres break surface and are then  held only by shear adhesion between the fibre and the resin.  The detail of the CF frame must be altered to allow for this.  Likewise the bearng pressure /wear that CF can withstand when in contact say with strings or hitch pins is inadequate for most duties in a piano so inserts must be placed to allow for these contact points, or the geometry altered to contain the stresses.


Despite these challenges we are sufficiently confident we can succeed that we have already instructed building of a first prototype piano with all carbon fibre construction.  It will weigh only about a quarter as much as a traditional piano so we look forward to an inaugural broadcast piano recital from an Airbus in mid Atlantic!


Cost Engineering

Cost is a critical matter for this advanced technology piano.  The bridge agraffe components in original concept and thus manufactured to extreme accuracy  tolerance costs about £15 per note..


We have embarked on a cost engineering exercise which has resulted in a pressed stainless component of identical performance at one quarter the cost.  This required  careful testing and development of appropriate decoupling between the knife edges and the agraffe body without incurring uneven support of each string over the knife edge. Similar cost saving study is in progress for the  carbon fibre sound board..


Professional artists have commented that a baby grand 1.68 meter  Phoenix piano of this concept matches in performance a traditional concert grand 3 meter piano of traditional build. We think this is no great exaggeration and conclude that on the basis of like performance the Phoenix concept results in a very cheap quality concert instrument.  Indeed we use one for our own recitals occasionally at the behest of our club members.   Just as car enthusiasts want a long bonnet on their Rolls Royce, concert artists will not be happy with playing a tiny piano on stage.  Anyway the larger Phoenix pianos are even better, so this is not a valid commercial selling point. But for private use in a small home or as a practice piano in an academy one could not wish for a better instrument.


Marketing  and Market Position

The new Steingraeber-Phoenix with fibre composite action, bridge agraffes , a carbon fibre soundboard plus combined sequenced  hydraulically operated una corda and half blow pedal and with 8 extra dampers to allow for improved upper register sustain will be shown at the forthcoming  Frankfurt Piano Fare in late March 2010.  Sales and manufacturing  rights are licensed to a prestigious Piano distributor in America.


 We attempted to enter the Steingraeber-Phoenix for a Queens Award for Innovation , but the Palace Administrators disallowed entry on the politically correct premise that our Company had no paid employee on the project. They stated this was a decision by the Duke of Edinburgh himself which frankly we regard as being grossly “economical with the truth” because it is totally out of character.  We immediately entered the piano for a similar award in Germany, the heartland of piano development, and won first prize outright. (5000 Euros)  We were not only in competition with other pianos but also with architecture , house furnishings and paintings. Unless the development of advanced technology pianos is encouraged  then classical music for piano will die just as the British piano industry died when it lost its technical lead to Germany. 


Until the mid twentieth century  the close liaison between artist composer and piano builder such as  Beethoven had with Broadwood, Liszt with Bosendorfer and Chickering and Chopin with Pleyel fueled the enthusiasm for new style compositions.  That all died when financiers assumed control of the lead piano companies  and applied their strictures which stifled investment in technical advance.  Now such advance is in our opinion beyond the capability of these big builders who are constrained to pursue distasteful and sterile policies of competitively commercial/financial attack on their competitors   without regard to the long term consequences for their own future and who have no understanding of what artists really need from their pianos so discussion with artists is impossible.  One such Company  even boasts their design is so perfect that it cannot ever be improved so they have stopped change in concept of any significance for over a century.   Their design is now outdated and the quality of production variable and deteriorating. The exception we see is Yamaha who have focussed attention on economical mass production to meet a lower echelon of cultural demand with consummate success, but these pianos are apparently of little interest to lead artists who mostly decline to play them publicly.  The policy has enabled them to seize a huge market share for learner pianos and for budget instruments in the home.


The trade of budget piano building is now firmly in the hands of the Chinese. Chinese piano quality is improving in leaps and bounds. There is probably room for only two European builders of premium calibre in Europe.  The ones that survive will be those who innovate to keep technically ahead.  Dozens have failed in recent years and their famous names now belong to the Chinese.  The last great British piano company, Kemble, closed a few weeks ago a victim of stagnation and the recession.

Steingraeber-Phoenix thrives and will carry the flag, but although it is a British design it is of course German built by a great Company of historical reputation who built the piano Liszt used in his Bayreuth home and still present it in recital.  Gt Britain has alredy destroyed its skill base in this art where once it was the un-challenged World leader.


Amazingly the cultured profession of piano design and building is populated by some of the most unsavoury characters in business who seem not to hesitate to steal ideas or trade, or indeed cheat clients wherever  the opportunity arises. Disguised commision seeking and bribes abound.  Caveat emptor if you are thinking of buying a piano.  This is in sharp contrast to experience in other engineering research work. where trust and a man’s word were respected .  

In this environment the obtaining of strong patents for innovation is essential.  The cost of this is a huge imposition on the work, and of the same order as the cost of development itself.    The EC should address this issue


 Richard  Dain,  a graduate  in Mechanical Sciences of Clare College Cambridge, pursued a career as a research and design engineer in many fileds.  Initially he worked under the re-assembled engineers from Frank Whittles Jet engine team on gas turbine design and testing.  Then after an apprenticeship in Switzerland under Prof Holfelder ex chief designer of Junkers Aircraft , he began designing advanced high efficiency diesel engines both of very large and very small size.  The latter has been produced by the millions in the UK and the large engine is still in production 40 years later.


This was followed by an appointment in Davy International where he pioneered processes and plant for Steam reforming, Ammonia and Methanol production, Phosphoric and ammonia fertiliser production,Solvent Extraction of copper and uranium  from lean ores, the production of powder metals in particular tool steel, the continuous casting of steel billets in vertical and horizontal machines.  In this capacity, as research Director he was responsible for all functions from initiation of the idea to its first commercial sale and implementation.  The copper process and the powder metal process now account for the bulk of the worlds production in these fields.  The steam reforming furnace remains the norm for this process even many years after its first build. 


For the last ten years of his formal engineering career he partnered  with Prof Sir Hugh Ford in Ford and Dain Research Consultants.  That partnershipassociation continues though is no longer  trading actively.  Sir Hugh has advised on and encouraged the piano research work. The last project undertaken was as Eexecutive Consultant to British Rail for the specification and implementation of the 225 high speed trains on the East Coast main Line.  A project that for the first time of any major project in British Rail was delivered on time and within budget. Dain regrets that the trains were designed to tilt for high speed service but political interference resulted in their never being used in this mode and then dispersal of the leading British technology abroad.  Before this he was Engineering Director of Howard Rotary Hoes and was involved in design of a grape harvester and sundry cultivation machines.


Pianos and piano playing have been an obsession since his school days. Even in his 81st year, he occasionally lectures about  and demonstrates pianos.  The opportunity to use his engineering experience to take these forward has been a lifetimes’ ambition .   He is supported and encouraged in this by Geoffrey Sapsford , one of the most experienced and skilled piano technicians in Europe. Geoffrey lends his sensitive ears where Dain’s  deaf ears, damaged by years of gas turbine testing,  prove deficient


Dain runs a modest sized but model farm where he grows cobnuts and Walnuts. As well as keeping a concert hall for piano recital and studio for  world standard recording of piano.  The Farm abounds with innovative  labour saving machines.  Included in the latest additions are a nut cracking machine for cobnuts which  in size and cost is  roughly a tenth as much as the big commercial plant that do this duty elsewhere , and a mechanical harvester developed from a problem Italian machine.  A plant for ultimate quality virgin  nut oil extraction is under construction.  This will be the first such plant in the UK.  Secondary products will be fuel briquettes of nut shell pulp, nut fudge and soap.

His constant complaint is interference in all these activities by civil servants and local government officers  with other agenda for personal gain  who know and care nothing for technical advance. 

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