What accounts for a truly remarkable concert grand?
Why do the best artists of any given time prefer to play a particular instrument? What demands do today’s concert grands need to withstand?
What, then, makes for a successful concert grand piano? From Bösendorfer’s perspective, it is particularly important for a concert grand to be deployable in various applications: from an accompanying instrument in chamber music in small venues all the way to a piano concerto in a large concert hall with an audience of thousands. These applications are worlds apart, yet an outstanding concert grand ought to be able to handle the full spectrum. In either case, sound quality is paramount. On the one hand, a grand piano needs sufficient power and volume to be heard over an entire orchestra when necessary. On the other hand, it should effortlessly produce warmth and a singing tone, which are essential for chamber music or lied accompaniment. Ignaz and Ludwig Bösendorfer were convinced that grand pianos should not only sound technically brilliant but should also inspire pianists and audiences with their sound. For the pianist, a flawless action and playability are a given; they make the best possible control and security possible. Add to that the ability to project tone and the length of a tone—especially in the treble range—and the ability to transport these qualities to the last row of a hall even in the softest pianissimo in order to enchant the audience.
Bösendorfer grappled very intensively with all of these topics in 2011. This ambitious project was then launched in April of 2012. Such a multi-layered endeavour can only succeed if all of the company’s potential strengths, from apprentices all the way to management, are able to make their valuable contributions in a motivated and goal-orientated manner. In addition to the constitution of the core development team, significant project areas and concrete topics were defined. The deeper we delved into a given area over the course of a discussion, the more questions inevitably arose. At first, we therefore came up with more questions than answers: What accounts for the identity of a Bösendorfer grand piano? What exactly do today’s pianists expect from a concert grand? What are the requirements in terms of today’s concert industry? What role does the overall stability of the piano play in terms of extreme stress, changing climatic conditions and frequent transport? The right questions are very important and often the only way to recognize and work out an approach to solving a problem.
Vision set: the Ultimate Concert Grand
Bösendorfer set a goal to build a concert grand that carries on the tradition and identity of the Bösendorfer sound while simultaneously fulfilling all requirements of a modern, contemporary concert grand piano. We subdivided this enormous undertaking into four project phases: basic research, specification of concept, experiments with existing concert grand piano models and the realisation of the new grand piano. All existing realities of the earlier concert grand were continuously called into question during the four project phases. We thought in every direction—nothing was impossible or too crazy to consider. The entire acoustic mechanism was analysed to be able to judge the physical and acoustically relevant processes and interconnections of the construction. The string scaling was analysed, for example: the string lengths themselves, the division, for instance the meaningfulness of 3-course bass strings in a certain range, the displacement of several courses from the midrange to the bass, transformation of tensile force distribution of the bass, midrange and treble ranges—and of course their effects on the piano’s sonic identity.
The greatest challenge lay in the further development of the resonance case principle, which is crucial for the typical, richly vocal Bösendorfer tone colour, because a maximum of resonance and ability to project sound should be achieved. The acoustic construction is thereby the most important and decisive area for building an outstanding concert grand piano. This project’s success lived or died on optimizing the efficiency or vibrational capacity and vibrational freedom of the soundboard. Merely reworking or correcting the construction was insufficient. We therefore took the opportunity not only to further develop the grand piano’s construction, but to bring it to a new and contemporary level. We used computer calculation models for the string scaling design and structural analysis and 3-dimensional CAD construction tools. We combined CNC-supported parts manufacturing with the abilities, knowledge and necessary feel of our experienced artisans for the sensitive materials.
Before a prototype can be manufactured from what was in many ways an entirely new construction concept, we performed tests of the solutions we developed in order to determine whether they could achieve the desired effect or change. In the first phase, we put component parts such as soundboard base, ribs and bridges under the calculated pressure loads, which were then measured and checked. In a second step, we integrated as many parameters of the new design as possible into an existing concert grand. Parts of the rim construction were milled and a new soundboard base, including ribs and bridges, were inserted into the altered construction. These first concrete findings were very important for the detailed engineering of the component parts; moreover, they served as an initial evaluation of the basic concept. In the next step, the final design and the corresponding construction blueprints for the first two prototypes were drawn up.
Significant design features of 280VC - Vienna Concert
A lot is new and has been reworked and optimised. One example is all parameters of the string scaling: the length, size, tensile force, division, alignment and positioning of the individual sections, the selection of the 1-, 2- and 3-course bass strings, proportion of the tensile force load between the bass, midrange and treble ranges, as well as strike lengths and strike line, and much more. Using computer-aided design software it is possible to visualise, calculate and formulate all processes optimally in terms of inharmonicity curves, load values and tensile strength distribution, in order to achieve a maximum of balance, stability and vibrational ability and oscillation period. In order to maximize the sonic potential in the treble range, we tested two variants in the first two prototypes—one variant with and one without a duplex system near the string attachment behind the bridge. The results clearly spoke in favour of the duplex version: The bell-like sonic component and the sonic, dynamic shaping potential tipped the scales in favour of this version. Since the string scaling significantly determines the design of many parts, it was designed and adjusted in a forward-looking manner in consideration of all elements it affects, including the subframe construction, cast iron frame, keyboard, shape of the case, etc.
The 280VC’s case construction was made traditionally as a typically Bösendorfer crossbeam construction. For reasons of sound, we use solid spruce and beech first and foremost. However, this case construction also contains several innovative elements that are only possible thanks to modern technology. The 3-dimensional construction method makes possible highly precise subsequent work on all wooden connections surrounding the case elements, case struts, as well as the crossblock and the keybed with unprecedented precision. This resulted in an enduringly stable and exceptionally solid foundation for further connection of subsequent elements. The bottom case design was made to form a closed unit, in contrast to earlier constructions. The case wall also traditionally consists of spruce tonewood in its core. The double beech inside and out are reinforced and stabilize the case wall. The sonic aspect of spruce tonewood as a core material remains entirely untouched in this process.
The most innovative element
By “acoustic enclosure” we mean the unit comprised of the bottom case, soundboard, ribs and bridges. The basis of the design is a 3-dimensionally designed model specially tailored to the shape of the piano. It is similar to a curved ellipsoid segment which is transferred to all parts of the acoustic enclosure with the greatest precision. The number, placement, sizing and forming of the soundboard ribs is precisely calculated to the actual pressure ratios based on the technical considerations of the diapason. Through the precise constructive basis of the 3-dimensional model and optimally aligned monitoring of the actual changes caused by the prevalent pressure ratios, we were able for the first time to trace the processes in the acoustic enclosure exactly and take the dimensions and regulation into consideration in the fine-tuning. This had a positive effect on the resonance characteristics, the efficiency and the general response characteristics of the soundboard, which is the most important sound-emitting element of a grand piano. This is where the music plays, so to speak, and it is where the wheat is separated from the acoustic chaff.
The construction of the cast iron frame is orientated towards solid stability and statics. The cast iron frame was also designed as a 3-dimensional model and drawn using CAD software. The height positions and unions of the various struts and bracing elements of the frame structure can thereby be optimally sized and positioned, achieving a maximum of stability with minimal mass. We manufactured the frame model for the sand moulding ourselves based on the one from the foundry in Enns, Austria which they cast for the prototype. At the same time we prepared the cases and the soundboard ensembles for the prototypes. The cast iron frame, case and pin block need to fit each other precisely, although these parts are manufactured entirely independently of one another.