Bluthner was reprivatized in 1989, and its pianos, cherished by music lovers everywhere, are still manufactured in Leipzig under the directorship of Julius Bluthner’s great-great grand son of Ingbert, and his son’s Christian and Knut. The aliquot scaling system uses a fourth string located above the treble strings, which is not struck by the hammer but free to vibrate in sympathy. The extra strings are tuned an octave higher than the actual note and offer enriched over tones and harmonics to the piano’s upper register. Bluthner patent action was used in grand pianos until the 1920s.
Dates and serial numbers when the pianos were manufactured