harmonic piano

When replacing the pinblock, it means that the piano requires a deeper overhaul, including the replacement of the strings. At that point, the piano is disassembled and it is possible to check the residual tension by measuring the difference in level between the bridges and the ends of the vibrating part of the string (i.e., relative to the tips and agraffes in the various sections). If necessary, the frame must be removed and the soundboard tension restored, or the frame supports lowered to ensure that the strings exert the correct pressure on the bridge.

Whether it is necessary, unnecessary, or what type of intervention needs to be done can only be determined after disassembling the piano, because it is not certain that if the piano shows zero tension when measured while assembled, it will show the same situation when disassembled.

Clarify, ask what they intend to do and why. And based on which assessments. I believe they have quoted for a complete job. How old is the piano?

insightful question from giovannig asking about the age of the piano!!!! I believe he is also referring to the amount of tension on the soundboard. The opinion on "how much" to load the board is controversial. It would seem that with the age of the piano, the tension should decrease... even in the bass, very little. However, as giovannig wisely advises, it is necessary to verify the two measurements before and after releasing the string tension....A great job!!!!!

it is correct that older soundboards should be loaded less; sometimes a difference of just one millimeter is sufficient. The term 'load' (carica) is often used improperly and should refer to the "residual force" on the strings, their curvature, or rather the convexity of the soundboard. A new soundboard is produced with a curvature of 8 to 12 mm, and it is not even mathematically predictable whether it will return completely or partially once removed from the clamp. Some manufacturers have also tried using pre-shaped, arched strings.

Anyway, in addition to the level difference, the curvature can also be restored; in the 70s there was a masterclass at Burger Jacobi where they demonstrated an interesting method by which one could intervene on the bridge, giving it the necessary curvature.

From a practical point of view, if the piano sounds good before disassembly, it is inadvisable and of little use to intervene at these levels. I have a Bechstein from the 1920s that sounded excellent before disassembly; upon measurement, the residual "load" was still sufficient and I did not alter this parameter. On the other hand, I have had to lower the frame on several vintage Steinways: an old teacher of mine used to say that no matter how much it bows, a soundboard certainly cannot sink below the horizontal level of the strings.

There is no precise recipe. I asked for the age because if it were 60 years old, the intervention might make sense; for younger pianos, it would seem strange....

Dear technicians, it would be preferable to show us mortals some photos of what you rightly claim, in my humble opinion.. THANK YOU

We all agree that, with advanced age, it is good to check that the soundboard is lightened in terms of load. Dear Saverio, this thing is not visible to the naked eye. The load should be measured with a centesimal comparator (see photo in the text by G. Bettin published by Ruggimenti)

THANK YOU!!