(Ger. Tangentenflügel).
A keyboard instrument whose strings are struck by freely moving slips of wood resembling harpsichord jacks rather than by hinged or pivoted hammers. A 16th-century pentagonal octave spinet by Francesco Bonafinis in the Metropolitan Museum of Art, New York, was originally constructed with jacks, but these were later replaced with striking tangents. The date of this instrument’s conversion into a tangent piano is uncertain, but evidence suggests that the conversion predated Cristofori’s invention of the hammer mechanism around the year 1700. The most important instrument of this type was the Tangentenflügel said to have been invented in 1751 by Franz Jakob Späth the younger and made by him (in partnership with his son-in-law Christoph Friedrich Schmahl after 1774) in Regensburg. The tangent piano principle was, however, incorporated in a number of other designs both earlier and later, none of which can be shown to have had any direct connection with Späth’s. It is embodied in the actions devised by Jean Marius in 1716 and C.G. Schröter in 1739 but not published until 1763; and a grand piano action patented in England in 1787 by Humphrey Walton (no.1607) altered the ordinary square piano action by making the hammer propel a padded jack-like striking element towards the strings. In addition, a number of surviving harpsichords and virginals were converted to instruments of the tangent piano type simply by replacing their jacks with shorter slips of wood and then shifting either these or the strings so that the short jack-like pieces would strike the strings from below when the keys were depressed.
None of these converted instruments, however, includes the refinements found in Späth and Schmahl’s instruments, of which all the surviving examples seem to have been made after 1790. The action of these instruments includes an intermediate lever to increase the velocity with which the jack-like striking element is propelled towards the strings, as well as a large assortment of tone-altering devices, including means for raising the dampers, for introducing a strip of cloth between the striking elements and the strings, for shifting the striking elements sideways so that they strike only one of the two strings provided for each note, and a buff stop that mutes the strings by pressing a piece of leather or cloth against them at the nut; moreover, in several of the surviving examples one or more of these devices can be used separately in the treble and bass. These instruments look very like grand pianos of the period and, as in pianos, the loudness of their sound is determined by the force with which the keys are struck, although the action is far less complicated. Their sound is very beautiful, especially when one of the muting devices tempers the somewhat metallic sound of the bare wooden striking elements against the strings.
The conversions from quilled instruments must be thought of as makeshifts and the tangent piano actions of Marius and Schröter were experimental constructions, each employed in only a single instrument (if, indeed, any instruments employing them were ever built), but the developed tangent piano is neither an experiment nor a compromise. Rather, it is a valuable instrument in its own right, and is the only one of many short-lived 18th-century keyboard instruments to survive in sufficient numbers for it to be judged on its merits. The rest, including two developed by Johann Andreas Stein and a number produced by the highly inventive Parisian makers of the period, have vanished entirely, leaving nothing but the enthusiastic claims of their inventors on which to speculate.
H. Herrmann: Die Regensburger Klavierbauer Späth und Schmahl und ihr Tangentenflügel (Erlangen, 1928)
S. Pollens: ‘The Bonafinis Spinet: an Early Harpsichord Converted into a Tangent Piano’, JAMIS, xiii (1987), 5–22
S. Pollens: ‘An Early Tangent Piano’, IMSCR XIV: Bologna 1987, ii, 286–7
S. Pollens: The Early Pianoforte (Cambridge, 1995), 27–42, 157–69, 214–23
S. Pollens: ‘Christoph Gottlieb Schröter: Inventor or Fraud?’, The Early Harpsichord and Pianoforte, ed. C. Mould (forthcoming)
EDWIN M. RIPIN/STEWART POLLENS