Bösendorfer – An Insight into Viennese Craftmanship
Our staff are not only individual dedicated craftsmen but also true team players who work together with great dedication to build our legendary instruments. We are pleased to invite you to tour through our factory in these following pages, where we will endeavour to give you an insight into the many skilled and varied processes that go into creating a Bösendorfer.
Resonance Spruce – ever since our piano factory was founded in 1828, Bösendorfer has had a clear goal: the inspiring sound – “Der Klang, der berührt”! In order to reach this goal, the strictest quality criteria are laid down for the selection of materials. This begins with specifying unique resonating Austrian spruce tonewood: no other piano has even remotely as high a percentage of spruce as Bösendorfer. Thanks to this wood’s ideal ability to carry sound along the grain, a sound velocity of about 4000 to 5000 metres per second can be achieved. In addition to spruce, red beech, maple, hornbeam, linden and alder are the main woods used for constructing Bösendorfer pianos. Only trees felled in winter are used: the low sap content of the wood during this season is ideal. Only spruce trees from the Austrian Alps that have grown at an altitude of over 800 meters above sea level and thereby exhibit especially close and sonically ideal grain structures are used for a Bösendorfer. Hillside position and tree growth play a significant role in selection. Trees from northern hillsides are preferred due to their slow growth.
The time factor
Time is another significant factor in building the perfect instrument. Bösendorfer forgoes technology-based drying and gives wood the necessary time of up to five years to dry naturally in the large 4500 m2 timberyard in order to obtain ideal properties for subsequent processing. This wood is never exposed to the excessive heat of kilns which can compromise strength and acoustic properties. Next, the wood with a size between 20 and 80 mm is cut for the first time; the bark, splits, knots, discolourations and embedded resin are removed. The moisture content of the wood, which is only about 12% after drying naturally, is then further reduced by being stored for c. 6 months in a climate-controlled room with a constant temperature of 26°C and a relative humidity of 30% until the targeted moisture content of 7 to 8% is reached.Then the real piano construction can begin.
Handcrafted from the very beginning
In the mill room, our experienced craftsmen pay careful attention to the individual properties of the wood – when sawing, planing, routing, joining, glueing, and sanding. For the soundboard, complete absence of knots, and an especially regular parallel grain structure as well as a consistent colour is sought. In pursuit of excellence, they strive to achieve the best results both acoustically and visually. For milling the individual parts – such as ribs, bridge, pin block and outer rim – over 1200 different jigs are used.
The pin block – guaranteeing tonal stability
The extremely robustly designed pin block anchors the tuning pins. This construction holds the transferred string tension of up to 20 tons for generations. For the individual layers of thepin block, quarter sawn maple and red beech are used. Three 7mm maple layers are glued cross-grained to one another, then glued to a red beech baseboard and finally capped with a beautiful 1.5 mm walnut veneer. The pin block is now fitted with utmost precision to the underneath of the cast iron frame. With a metal blade 0.2 mm in diameter, the precise fit between pin block and frame is checked. The open pinblock construction allows firmer and more secure seating of the tuning pins which in turn gives technicians more direct control.
Bass string making
At the start of the bass string, the core wire is wound by hand in the opposite direction to the top layer with flatly rolled copper wire. This special method of bass string production, which produces unique sonic properties, can be found only at Bösendorfer.
Bösendorfer frames are the most elaborately made frames in the industry.
The heaviest component of any instrument is the cast iron frame. GG18 cast iron quality is used, as specified by us in order to meet our particular elasticity, strength and absorption property requirements. The traditional sand cast method is used for all Bösendorfer frames. All frames are stored in the open-air for c. six months. This gives the iron frame sufficient time to rid itself of any internal stress that arose from the different cooling time in different parts of it. In the frame department, the frame is assigned a work number and all additional parts of the instrument are, from this point on, individually fitted to this frame. The frame is machined with highest precision by a state of the art CNC machine. This milling process creates the exact contours required as well as drilling all the holes for agraffes, hitch pins and mounting screws. A special feature of Bösendorfer grand pianos is their independent capo d’astro which is hand fitted to the frame. Only this method allows precise determination of string height and position. The original string height consequently can be restored even after 100 years of use. After quality control, the frames are ground, filler sprayed and sanded by hand in several steps. Depending on the model size, this process takes up to 10 working hours. After the basic paint work, the frame is sprayed with a bronze-coloured paint typical of Bösendorfer. Finally, it is sprayed with a clear top-coat, the last of a total of 10 coats.
The sound is given body.
The tonal character and our typical colourful timbre are directly related to the construction and design of our instruments.
The resonance case principle
Bösendorfer is the only piano manufacturer in the world to build according to the Viennese piano making tradition. The whole body, and not just the soundboard, supports sound formation, similar in principle to a violin. Whilst other manufacturers glue the soundboard into a rigid laminated hardwood case, we have a completely different construction. The inner rim and keybed is built by glueing together individual components mostly made from resonance spruce. Then the outer rim, whose core consists of 10 mm quarter-sawn spruce, is carefully glued onto the inner rim. A complex series of vertical grooves allow it to be formed. When a note is played the integrated spruce components become acoustically active, forming a complete resonating body, giving the whole instrument an unparalleled resonance.
Crowning the soundboard
Bösendorfer crowns the soundboard of each grand piano with specially-cut and shaped ribs instead of forcing the crown with compression from the rim as other manufacturers do. This process ensures that the exact crown (soundboard curvature) of Bösendorfer soundboards remains unchanged throughout their lifetime for optimum tone. Subsequently, during the setting of the down bearing through the most delicate handcrafted procedure, the height of the glued-on bridge is adjusted. It is through this that the pressure exerted onto the soundboard from the strings is precisely regulated. This is necessary in order to put the soundboard under optimal elastic tension in order to make the perfect transfer of string vibrations possible. Before the final gluing of the soundboard to the inner rim, the bridges are notched with scrupulous precision, the bridge pins inserted and the soundboard lacquered.
Cast iron frame assembly and stringing
Once the entire resonating case of the Bösendorfer has been created, the cast iron frame is inserted and screwed down. Agraffes and hitch pins for the strings are installed, after which felt strips are put in place to dampen unwanted harmonics. Bösendorfer uses the complex system of single stringing for all our grand pianos, rather than simple looped stringing. Overtime this increases tuning stability and is particularly service friendly. Each string end is made into an eye by hand. The bass strings, produced in our own string manufacturing facility, are also made by hand. Once the piano is strung it receives its first chipping (pre-tuning).
The spectrum of design possibilities ranges from our hand-polished, high-gloss black to the wood veneered “Artisan” model, beautifully crafted with the finest inlaid detail. Our craftsmen are masters in the art of marquetry, gilding, carving and wood turning. Bösendorfer is proud of being able to present sensational creations to a global audience in cooperation with some of the world’s most famous designers and architects. These names have included Hans Makart, Theophil von Hansen, Josef Hoffmann,and Hans Hollein. Our latest collaborations are with Audi Design, Porsche Design Studio, and Edelweiss Industrial Design.
Manufacturing a classic piano in black high-gloss polyester is a very time-intensive process. Eight coats of polyester are necessary for a perfect finish; and once sprayed the parts have to have a drying period of a minimum of two weeks before they are sanded and burnished.
For veneered models exclusive veneer is purchased and then carefully prepared in painstaking detail before being glued onto the instrument parts and polished. Some models require marquetry inlays that need to be prepared, and in special cases, elements such as hand-carved figurines must be positioned.
Depending on the veneer up to three different versions are possible: high-gloss, semi gloss and open-pore. Whatever the finish, the customer acquires a masterpiece – asboth a musical instrument and as a work of art; an instrument that can delight the eye and ear each and every day.
Interface between pianist and sound
The Bösendorfer grand piano action and hammers are made by the Renner company according to Bösendorfer’s own specifications. The action geometry has been painstakingly developed in close cooperation with artists, teachers and technicians. Every set of hammers is checked for quality and sound before being used, and rejected if necessary. Keyboards manufactured to Bösendorfer specification are sourced exclusively from German keyboard specialists. The keys are made of spruce (horizontal grain orientation) and the key frame is made of spruce and oak. The upper action assembly is then mounted on the key frame and adjusted in each individual piano to our own exact specification. The action’s several thousand parts are fitted and precisely aligned by our craftsmen.
Attaching the dampers
The damper rails and dampers are then fitted. Attaching the individual dampers is done with great precision, as they need to lift together absolutely simultaneously when the sustain pedal is depressed. During the action assembly process 2 further tunings take place to obtain optimal tuning stability.
All tonal and action aspects can be adapted to your individual request.
After the initial regulation of the action an hour long stress test takes place on our piano playing machine -this simulates an intense performance by a pianist. All moving parts are subsequently meticulously regulated once again .Only after a final tuning along with a rigorous final inspection by a master craftsman is the instrument permitted to be moved on.
Both prior to, and after voicing, the technician performs a concert tuning. The piano is also tuned prior to despatch. “Voicing” is a process performed on the hammer heads to bring out the full tonal potential of the piano. It involves using needles to adjust the elasticity of the hammer felt. Via selective needling of the hammer head with needles of varying strengths, at different angles and parts of the hammer head, the tension within the felt is altered and manipulated. This is decisive in determining whether an instrument has a bright or a more mellow tone. This is one of the most skilled and sensitive processes in the entire manufacturing process. Through experience and skill the technician brings out the instrument’s tonal virtues in accord with the customer’s desires. Every instrument has its own special nuances and particular tonal properties due to the use of natural materials such as wood and felt which will never be exactly the same from one piano to the next. These individualities are recognized and cultivated by the experienced concert technician. The prerequisite for this work is a perfectly regulated and tuned instrument.
Another important task is aligning the hammers parallel to the strings. With a sandpaper file, the hammer heads are carefully adjusted. The una corda pedal is checked and adjusted for effectiveness and evenness. Lastly, the hammer heads are ironed to smooth their contour. The result is an instrument that in its tonal beauty and balance is convincing throughout its entire compass.
Intensive Quality control
Each Bösendorfer instrument must meet strict quality control standards before its debut – attesting to an unprecedented reputation since 1828.
Regular quality control
Since the company’s founding by Ignaz Bösendorfer, quality has always been of paramount importance. The successful principle of personal responsibility has remained unchanged: work by the best masters of their fields is checked by each of them and then rechecked by department supervisors after the completion of every single production step- only the best is acceptable.
A final inspection upon completion and after any voicing adjustment to a customer’s request is performed by Bösendorfer’s technical director himself. This final painstaking inspection assures that the instrument leaves the factory in impeccable condition. The process slip, the “Lauf-Zettel” that accompanies the instrument through its entire production process is then finalised and filed in Bösendorfer’s archive, which has been maintained for over 100 years and survived both World Wars.