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Articles - The Vertical Viennese Fortepiano


Historical Description of the Vertical Fortepiano Invented by
Wachtl and Bleyer in Vienna (1811)

(Historische Beschreibung der aufrechtstehenden Forte-Pianos,
von der Erfindung Wachtl und Bleyers in Wien)

Allgemeine musikalische Zeitung (Vol. 13, Intelligenz-Blatt
November, 1811), pp. 73-77.

Translated by Edward Swenson

That it may be necessary to acquire a knowledge of physics, acoustics, mechanics, and mathematics in order to invent and produce a good and functional upright pianoforte, was believed as little by the piano makers of the past as by those of today.... The most important factor [is] to give the diameter of the strings a proper proportion, since anyone who simply trusts the wire manufacturers is often shamefully deceived...One often finds under two wire sizes one wire thickness, and under one size, two wire thicknesses. Furthermore, one can very easily be convinced that the wire manufacturers do not all use the same [wire] gauges. We gave our own fork-shaped wire gauge [Saitenlehr] the following adjustment: between two strings a and b whose diameters stand in a 1to 2 relationship, 15 steps were inserted, and in such a way that if one should mark down the diameter of all the strings in their proper order, a geometric series would emerge. If the instrument is to have a homogenous tone, then the thickness of the strings must increase and decrease in geometric proportion. Consequently, we have seventeen numbers from a to b. The local as well as the Nürnberg strings only have six wire sizes between a and b, and even if one should insert half sizes, this would still only add up to 15 sizes whose half sizes are frequently the source of errors.

Most of the refinements had to take place in the stringing scale [Mensur]. Due to blind tradition and so-called improvements, this had become so out of proportion that one could no longer recognize the original octave relationship. How much the uniformity of sound suffers under a misshapen scale and a stringing whose numbering has no proportion can be easily understood. Skilful hammer leathering can equally produce no doubt one could answer that uniformity of sound. Yes indeed, but how long will this forced uniformity last?

Based on a controlled experiment, for which two apparatuses and one monochord had to be constructed, we determined the length and diameter of the strings, as well as the most accurate tension for the tones f'''' and small f. On the basis of these tones, the other 47 insertable tones, which together have to constitute a geometric series, were developed and from this we derived our octave relationship of 1 to 1.9458608.

Considering the importance of maintaining tuning stability, everyone will concede how important it is to build the strongest possible case [Kasten] so that it cannot warp. But many might be unfamiliar with the fact that the weakness of the case structure [Sarge] can ruin the originally beautiful sound of an instrument. There exist many examples of the latter. Many a bungler is so fortunate as to get a pretty sound from his instrument. But should the case structure [Sarge] be made of inferior material or carelessly built, then the case structure shifts out of place and puts pressure on the soundboard through which it loses its free elasticity, and the sound becomes lost to such an extent that often nothing remains but a hammered dulcimer [Hackbrett] with a keyboard. (Hang a singer by the throat and then let him sing.) If one builds a frame in the usual manner, that is, with solid framing members, and furthermore even braces the sides, then one finds within half a year, on removal of the soundboard, that due to the tension of the strings, amounting to 90 centners [4,500 KG or 9,922.5 lbs] all the braces will have been compressed into the case wall by the depth of a line [bei einer Linie] deep into the walls [Wänden] and have now become quite loose. In order to maintain tuning stability, it is not enough only to build a proper frame with solid wood construction. A good frame must not only be (A) strong, but also (B) soundly built, in order to be able to participate in and reinforce the amplitude of the sound. In April 1808 we built the first case [Kasten] according to our newly developed method. This case did not suffer from the problems mentioned above, and furthermore it filled conditions (A) and (B) most adequately. In fact, the entire shape of the sounding-corpus [Resonanz-Sarge] with its beams and braces is constructed out of a layering of strips that are only one inch [ein Zoll] thick. On top of the first layer, the second one is glued in such a way that it covers and joins the seams [Fagan] of the first--and then follows the third layer identical to the first, the fourth to the second and the fifth to the first. Here the braces [Streben] cannot press in because they are intimately bound to the contiguous parts, thus lending the case a natural coherence, through which the exceptional acoustical purposes were very well met, since it is well known that a solid body is an excellent sound transmitter.

All of our wood is artificially kiln-dried. In this we followed the good example of Mr. Mündinger (a local citizen and master cabinet maker) who has been using such a method for the last twelve years. Only a few wood workers are aware of the advantages in treating the wood in such a manner. Most claim that only time dries wood out. But if one lets wood lie in the open air for fifty years, it will not dry to the point of being magnetic [?], something which does occur, however, within eight days if the artificial drying method is used.... The timber used for our soundboards and keyboards is steamed for forty-eight hours before going into the kiln. The hot steam of salted water penetrates all the pores of the wood and dissolves the resin found within the pores, and draws it out onto the surface of the wood where one can see it in the form of brown drops.

One can easily see that a soundboard thus treated will not only be more lasting but also more suitable for its acoustic function.

Some pianists have rightly remarked that the tone of our upright fortepianos seems too strident [grell] to the ear. This fault has been remedied when we started using a sound-cover [Schalldeckel] (an English invention)

In addition, our forte-pianos have only three pedals [Mutationen]: forte, lute stop and una corda. On request we will also install the bassoon and the Aeolian harp, but never the soundboard drum and the cymbals [Cinelli].

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