Hello. For a few years now, I have been involved in piano restoration and tuning. Every time I tune the central octaves they seem perfect, but the low octaves are not harmonic even though they are tuned with the tuner. I wanted to understand clearly how much lower the bass notes need to be tuned and vice versa for the highs. In practice, I am wondering: if I tune the octaves without beats, how do I make them increasing? And if I make them increase later, won't I have beats with the previous octaves that will therefore bother me? Same thing for the bass. Thank you to whoever answers me
Every piano has its own disharmony and the bass notes can be very disharmonious. Its partials are increasing and they must be made to combine with others in other areas of the keyboard. At the same time, as you say, a compromise must be found with the low octaves. Many checks must be performed on tenths, octave plus fifth, etc.; it cannot be indicated from a distance. I recommend the book by our friend Giovanni Bettin, which illustrates well how to perform these checks on both the bass and the treble. "Il pianoforte da concerto Steinway & Sons" - Rugginenti edition is the title. He naturally refers to the Steinway grand piano, so the procedures and results might be slightly different, perhaps, on an old upright piano.
