Tangent Piano / Tangentenflügel

An important type of piano in the second half of the 18th century

The tangent piano is indeed a very special keyboard instrument of the second half of the 18th century (later till the middle of the 19th century in some areas pianos were made with tangent action but they neither have the characters and varieties of the sound nor the concept of the greatest master or almost the inventor of it F.J.Spath who mastered this great invention already in 1750s) We do not have surviving tangent pianos of him (it is said he delivered one for instance to the Elector of Bonn in 1751 already) but we have the texts of those times which gives us this information that he was already making such pianos with many ''Klangänderungen'' which we can translate more or less to ''sound effects''

A tangent piano or pantalon without these ''Klangänderungen'' are probably no tangent pianos or pantalons! there are very few examples of them.

Clavecin Royale was basically a square piano with Stoßmechanik like the post 1786 square pianos with double action (with escapement) but with thin strings and bare wooden hammers with several hand stops which also did make a lot of these ''Klangänderungen'' which seems that it was really what specially in German speaking states (which we call Bündesländer today) loved and therefore made so many of them.

Known to us several but in fact more than these makers some ''Claviermacher'' were making tangent pianos based on Spath's model.
Many makers made pantalons which are simple action (either Stoß or Prell) square pianos with 2 or more hand stops and mostly with bare wooden hammers but having no dampers.

Today Michael Cole (Scholar) believes that a square piano without dampers, with bare wooden hammers is a pantalon and when it has dampers, then it is a square piano.
His German colleagues mostly disagree but at the end we should remember, in the 18th century they did not care what who calls all these ''Claviere'' !!

In on region they called Clavier to what we call a clavichord, in other places they called the clavichord a clavichord, or in other places the term Flügel was used for whatever like a grand piano or harpsichord or even a tangent piano! they even wrote their own names sometimes differently! something that no one does today!

So, speaking of Clavecin royales (made by J.G.Wagner and his pupils or maybe others who imitated) or pantalons adding them to the list of tangent pianos, all having hammers (pivoted or pivotless) had bare wooden hammers and thin strings with various stops, operated either by knees or hands or both. These were made mostly around 1770s to 1800.

A tangent piano like what Spath made and his pupils like Schmahl and Berner or others who imitated or copied his model could not be developed in the way other normal fortepianos could and there are strong reasons for that.

The most important of all is because of the increasing of the volume. A 5 octave Walter type grand piano could receive more notes, heavier hammers, thicker strings and therefore louder tone to reach 6 octaves within almost the same structure. Later being made structurally even heavier, the shape becoming more massiv like the next generation of 6 octaves from 1815-20 and so on. But it is impossible to have bare wooden hammers or tangents hitting thick strings. The sound will be brutally loud and ugly.
As Cello could become classic from baroque with ease and viola da gamba could not become a modern instrument or as the lute had to face its decline and give the guitar the opportunity to develop in quantity (volume) dimensions, the tanget piano also said goodbye to the music history until very recently that we had the chance to hear a few of them and even experiecing very few copies!


On all pianos the hammers which hit the strings are pivoted but on tangent pianos the hammers/tangents are pivotless. Of course we should consider the 4-5 or more handstops and kneelevers the tangent pianos have but we should remember that pianos (mostly square pianos) in the 18th century also had from none or one to 6 hand stops, pedals or kneelevers. (Mahr and Klein in Germany had 6 hand stops at the front, Clavecin Royales had 4 pedals or kneelevers, Swiss and French pianos had up to 5 pedals sometimes and in England 3 hand stops and a pedal was not so rare).

Tangent pianos were even made in 1720s but surely was mastered by Spath around 1770 and was produced in large numbers to many countries till the end of the century specially in 1790s by Schmahl in Regensburg.

Their craftsman who worked first with them and later in Hamburg was also known for his tangent pianos. Some less known makers in Germany and Italy also made many tangent pianos even in square form. In some rare cases upright tangent pianos.

The tradition was becoming less popular in Germany but in Italy there were still grand and square pianos made originally with tangent action or being later converted until about 1850!

Of course being leathered unlike the fascinating unleathered tangents of the 18th century with several stops.

The tangent piano is with or without its delighful sound imitations (stops) no less expressive than the normal fortepiano. The action is very fast and reliable, much easier to maintain than fortepianos and harpsichords but it can only sound expressive through a sensible touch. Like refined Stein pianos the tangent piano does not require power and force, therefore no escapement was needed to be made. 

Iin the music of that period no pianissimo like a pianissimo in the romantic period was needed. And by no means a too loud fortissimo.


The action of the tangent piano is based on the Simple Stossmechanik mit Treiber (with intermediate levers) which we can compare to Erard's double pilot action which was first used by Zumpe in 1780s but in England did not become in fashiod because right at the time John Geib made the English double action which had escapement.

We should remember than the intermediate lever is not an invention of Zumpe (nor the double action is J.Geib's invention) but these are all taken from the genius work of the earliest example of the pianoforte, Bartolomeo Cristofori's model.

The great advantages of the Spath tangent piano and its replicas is that (apart from the great sound it produces with all its varieties) the keys are very light, it is very easy to play and is very sensible like those of Stein. If the player develops his technique (which is not that difficult, incomparable to the very complicated way of playing on the clavichord) he/she can play easy, fast and very light (which is very important for the repertoire of the period with all its rapidness and flourid ornamentations etc.) but it also does not have a bouncing problem. It can only bounce if the modern player has learned and continued to play on the modern piano which requires a different technique. So if a modern pianist directly starts to play a tangent piano, we will hear some bounding but for those who have played frequently on the clavichord, harpsichord and other fortepianos like Stein or Walter, this is very easy to get used to.

So on a tangent piano we are dealing with a reliable action and touch which is capable of expressing the music of Mozart's earlier works up to Dussek's virtuosic passages of 1800-1810 music.

The touch is not to be compared with clavichord (some people link these both instrument because of the word tangent which is mutual with the clavichord, but in fact it gives more the feeling of something between the harpsichord and fortepiano.

In fact before Spath this instrument was invented by others several times! from the 15th century till Spath's great invention we read them describing a kind of harpsichord that has no plucking but jumping jacks which hit the strings!

We also read that probably none of them introduced the intermediate lever used by Spath which is necessary to give the player a great freedom of playing notes fast with ease with the minimum keydepth (keydip) which is comparable to Stein which is around 3-4mm only!

On a harpsichord based tangent piano of the 1730s (which is not survived) we have to use another finger technique...the tangents (or jacks) must receive a bit stringer energy to throw them up in the air while on a Spath model it happens with the slightest touch of the finger (although it is still jumping unlike Prellmechanik which is through a contrary motion which has a quick reaction)

On a Stein piano due to the short travelling hammer distance and 1mm distance of the hammer tail with the toung of the escapement you just need to move it for that 1mm and it hits the string so fast. On a tangent piano or English pianos which are all Stoßmechanik based actions you need a little bit of power to throw the tangent. On pivoted hammers you need much more of this to throw the hammer up in the air. But on a tangent piano it is still very near to Stein.

In theory who has played the fortepiano but not a tangent piano yet, can guess that strings being hit by bare wooden hammer or tangent can sound too loud and hard! but Spath model tangent pianos cared so intelligently about this that amazes everyone who tries his tangents in his hand. They are around 1,3-2 grams only, even max. 2 in the bass!

They jump freely within a register which is a box with square holes that are covered by leather so there is no friction like a hammer hinge or a hammer butt to reduce any movement. It happens extremely fast!


The dynamic

The tangent piano offers a wide range of dynamic from pp with una chorda to mp with una chorda, then bichord and then starting to play loud up to fortissimo within its own range.

The term ''within its own range'' is a keyword for understanding secrets and beauties of old keyboard instruments.

All these old instruments produce undescribably amazing sound mostly because of their limitations of compass, loudness, clarity and sonority.

All great historical keyboardist with sensitive ears know in theory and by nature that playing the fortepiano too loud means only dullness and unnatural. At the treble specially the pianist should play softer but with the same awareness and energy! this little chalange makes the sound of even bichord strung pianos (like most Steins and all tangent pianos) still singing and draws special attention which is by nature itself rhetorical!


The aim of creating this website is not only to give the reader/musician a bunch of historical information but also to deepen the understanding of this important instrument of the music history which had a great place in its own time and today after the rebirth of the early music (not about 100 years!) it is the time to turn faces and open our ears from not only the modern piano but also the known harpsichord and clavichord to this special instrument with all its possibilities it offers us for the music of cpe Bach and other Bach sons, Benda, Schobert, Rust, Müthel, Kittel, Neefe and many more who need more attention and being played on such relating instrument.


I would like to thank the two Tangent Piano scholars, Prof. Michael Latcham and Prof. Giovanni di Stefano whose articles were very helpful to find out more about this important instruments.

Very special thanks to Prof. Giovanni Di Stefano because of his support and providing numerous photos and correspondense regarding almost all surviving tangent pianos.