Basic facts about piano backs, "a super or extended compass as seven and a quarter octaves e.g. 88 notes. The 88 notes are made up of an average of 220 strings, the average string tension is about 170 lbs per string, with an increase of 15% in the bass, between the top and the centre of the compass the string lengths in octaves is increased in the ratio of 17:9 for each descending octaves, wire gauges increase by a half every six notes, down to the tenor area and more frequently there after. Particular consideration is made for string lengths to increase all the string lengths at a ratio of 17:9 especially in the bass it would be very impractical so the diameters of the bass stings are increased with nearly every note in the bass.
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Aug Neidhardt Berlin
H 128
W 140
D 62
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