Voicing

Voicing is the process of altering the density of the felt hammers that strike the strings. Hammers that are too soft can sound dull and muddy, while too hard can sound like breaking glass. Either state severely limits the pianists ability to play with expression and feeling. A properly voiced hammer will produce a more bell-like tone which will allow the pianist to actually alter the tone from warmer on pianissimo (softer) play to more brilliant and percussive on forte (loud) playing. 

Voicing can consist of filing or reshaping the hammers to eliminate string cuts in the hammer face, needling to soften, lacquer solutions to harden, or a combination of all these procedures.  It is necessary for tuning, regulation, and voicing to all be working in harmony to take an instrument from “nice” to truly sublime.