Claviermacher in Hamburg
According to Ernst Ludwig Gerber's Historisch-biographisches Lexikon der Tonküstler (from the end of 18th century) Berner was active in Spath & Schmahl's workshop in Regensburg before settling in Hamburg. There he made many tangent pianos and was well known for that.
He followed the design of his colleagues Spath & Schmahl in all details except that he used black keys for the accidentals, used mahogany veneer similar to English pianos which were in fashion in Hamburg and Scandinavian countries and also made sometimes tails in English, Walter, Flemish, French harpsichord style while Schmahl ones had round shape like Stein.
Another difference of Berner's tangent pianos to those of Schmahl is that he used double bridge (the brass section being divided from the long bridge which holds soft iron strings). This feature was not unfamiliar in German speaking countries. The famous Viennese piano maker Johann Schanz also made from the very early on, grand pianos (late 18th century) with divided bridge just like Berner at the same time in the north but mainly the idea must have became popular from England (in the early 1790s Broadwood and Stodart started to make such bridges) but even earlier in Germany there were clavichords made with divided bridge! so it is not necessariliy an English invention but we can assume that it was the late 18th century English grand piano which made Schanz in the South and Berner in the north to adopt this idea.
Schanz as a Viennese maker had to make pianos as viennese as possible though, while German makers felt free to adopt and adjust whatever idea they found useful from anywhere. Berner adopted more from England on his tangent pianos, because apart from the cut cheek and the lid but also the music stand the general looking is more or less like an English grand (specially because of veneering and white natural keys, mahogany case. The nameboard is typical Swedish/Danish.
The surviving tangent pianos are the following :
1- Private ownership (Germany) with typical Stein-Spath etc. tail dated 1796
2- Radbon Fortepiano Collection (Germany) with Walter tail (probably 1797)
3- In the museum of music in Copenhagen, belonged to Christian VII the Danish king, dated 1798 (with Walter tail)
The tangents, action, dampers, instruction and many more features are the same as Schmahl which is no wonder of someone working there for decades making the same thing sending it to ''All corners of the world''! (according to other 18th century sources)
The weight of tangents, their shape, stringing gauges (therefore volume and solidity and sonority of the sound) were never changed from at least 1780 to 1801 (in the workshop of Spath and Schmahl) except that Schmahl made ca.20cm shorter version tangent pianos as well as the longer ones which were around 210cm) and used overspun strings in the bass (one for a pair, the other one plain).
Tangent piano was a very popular instrument unlike what we would imagine today (being a special instrument).
The number of Tangent pianos by Schmahl alone is more than the whole surviving number of pianos by Walter and Stein (both being very well known at the time!)
Tangent pianos have light and rapid action despite having no escapement. Tangents are kind of ''Pivotless hammers'' hitting the strings like harpsichord jacks but with an intermediate lever between them and keys which makes the action much easier to play especially with a low key-depth (similar to Stein!) which can be directly compared with Erard's double pilot (which was originally a patent by the famous German maker in London Johannes Zumpe).
One of the reasons that the tangent action is very rapid is because the tangents are free and jump extremely fast, while this action's relatives (basically Stoss-mechanik) like those of Zumpe
(Simple action) or Cristofori/Silbermann (with escapement and even back check and intermediate lever altogether) or English grand action, non can be compared to the tangent action with its
fast reponse of the fingertips! it can only be compared to Stein pianos.
Appearantly German musicians of the second half of the 18th century appreciated only a very light and fast action and cared less for the little bit more volume of the typical English pianos.
As a matter of fact even the simple Prell-mechanik which has also no escapement is faster in response of the fingertips than simple-stoss action (which was also in common in Germany but indeed less than Prell-actions.
Stein's Prellmechanik has its own character and feeling for touch and all Stoss actions need to be played a little different, but the tangent action being a kind of Stoss action has still its advantages of being Stoss-mechanik but the same time having the fast response similar to the Prell-mechanik.
The tangent action was indeed not an invention of Spath but from da Zwolle (15th century) and maybe even earlier. Indeed in its simpler form but still ''jacks hitting the strings and not plucking''
In the 18th century the main maker of the tangent piano was doubtless Spath who introduced this instrument and made many of it and sent it globally to even Russia.
Later his son in law Schmahl married his daughter and made this kind of piano (but also normal fortepianos and maybe square pianos etc. as usual). Spath died in 1786 and Schmahl continued up to at least 1801. His sons continued longer till at least 1814 but mostly made the usual fortepianos.
Tangent piano was not only made by Spath & Schmahl and their pupil Berner but many more makers either made tangent pianos more or less similar to these three main German makers of tangent piano like Baldassare Pastori and some unknown makers in Italy but also many others who converted hatpsichords, spinets or pianos to tangent-action pianos.
A few examples exist even in England and Poland of originally made tangent action square pianos. In one case a Longman & Broderip grand but since it is prisioned in an unusual private ownership we can hardly have any information from this instrument.
In Germany there were a few more makers (with less importance) compared to Spath & Schmahl and Berner who made their own impression of tangent pianos. Mostly unsigned...
It is not absolutely clear if the ''Späthisches Clavier'' Mozart referred to in his letter to his father in 1777 was one of Spath's normal fortepianos or his well-known tangent pianos which were made at least as early as 1751 by him.
But there is no doubt that tangent pianos were known to Mozart and that he played on them, the same is about Haydn, cpe Bach and other contemporaries.
We don't know ''officially'' if they loved this kind of fortepiano or not but we should be aware that there were many of them made in these countries and had many buyers, so it is easy to accept that they must have been very favorite amongst musicians.
We can also imagine that someone like Beethoven may have found them less serious than Stein and Walter in his youth and no doubt for a period he used to play Streicher, Graf and such big and loud pianos.
So, performing the music around 1750 up to 1810 on tangent pianos is historically and stylistically very right.
More detailed information will be updated here but reading more about tangent pianos (articles by Michael Latcham and Giovanni di Stefano) is highly recommended.
Christian VII king of Denmark's king's Berner Tangent piano 1798 (now in Copenhagen museum of musical instruments)
Photo by G.D.Stefano
Pooya Radbon Collection's Berner Tangent Piano
Reinhardt Menger's Tangent Piano 1796 (Michael Günter playing)
All 3 surviving tangent pianos by Berner have divided bridge in the bass a feature more adopted from English grand pianos from early 1790s (but also seen on German
clavichords of the late 18th century)
The ''Walter tail'' is not necessarily being inspired by Walter or English grands. There were other German piano makers in the 18th century which made pianos with Stein action but made the tail like this in 1780s already. J.H. Silberman's piano being from 1770s had also no round tail like those of the Gottfried Silbermanns or Steins etc.
(Photo by G.D.Stefano)