usuall backcheck (wire) of act of piano is not regulation. But if it is possible to do double repetition of a sound, why not do?
The usual adjustment of the wire is so that the jack after the first blow of a hammer comes out. And it's stay on Hammer butt felt
Vladimir bends backcheck (wire) in such a way that after the first strike of the hammer the jack remains under Hammer butt felt . An jack can again and again with incredible strength and rapid alternation push a hammer.
What do you think about it's?
It's operation can make any man, I'm think. And yours upright piano must be do double repetition of a sound.
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