In contrast to the established free-reed manufacturing centers like
Saxony, or Black Forest, the harmonica makers in Bavaria were very small
manufacturers producing hand crafted instruments on demand
for the local market.
The name Wiesner is known for many free reed instrument makers in Munich. However, there is no evidence about their parentage. Maria Dunkel refers to Willibald Wiesner, Harmonikamacher, est. 1859, but also to Carl Wiesner, mentioned first in 1869. A company named Gebr. Wiesner, Konzertina und Harmonikamacher is known as of 1906 and which possibly belonged to the brothers Wilhelm and Josef. This manufacture survived World War I.
Josef Wiesner made bandoneons
under his sign during the time from 1925 to 1942.
He was known as very inventive, owning lot of registered
patents concerning improvements of musical instruments.
He constructed a bandoneon with a piano keyboard, presumably even before
World War I. Also a disposal to play any bandoneon free hand, in a similar
way to a symphonetta, is of his authorship.
The keyboard layout of the model shown below, is characterized as as Schrammelbandoneon. The Schrammel music has it's origin in a folk music style created by Johann and Josef Schrammel during the second half of the 19th century in Vienna and which influenced the folk music style of the surrounding regions including Slovenia, Hungary, Bavaria among others. The development of the keyboard layout started from the 130 voice rheinische Lage to which new keys were added, but in a different manner than for the Argentinian type.
Each note is produced in this model by 2 reeds. However, the sound differs clearly from dual reed instruments used in tango: There is no dry character and sounds far softer. The reason is because of the different construction:
The bass instrument side differs from the usual instruments in the lack of a dumper box. The dumper mutes the high partials of the bass and produces a soft sound similar to a cello. The sound of the overlapping range of notes from the left and right side does not differ significantly.
The large dimension of the cabinet compared with other dual simplifies the building of instrument variants with 3 or even more reeds per note. Also it may have influence on the sound color comparable to a damper case.
Furthermore the tuning is done
with a pronounced tremolo, for at least all the bandoneons I heard in Bavaria.
The softer sound is requested not to disturb other silent instruments
used in Bavarian ensembles, typically formed by two violins, double necked
counter guitar, clarinet, double bass.
The pictures below are taken from a Josef Wiesner
instrument belonging to Alois Scheungrab of Ampfing near Mühldorf am Inn
(Oberbayern), the last living pupil of the virtuoso Georg Weinschütz
of Munich (died in 1948).
The last two pictures are basically also a Wiesner instrument, but the cabinet was rebuilt by his owner, Alois Scheungrab. Note the heavy construction and the covered valve lever at the treble side.