Besides piano tuning which deals with the pitch there are 2 other components of musical performance that need to be adjusted periodically: tone (voicing) and touch (regulation). Piano keys and actions were designed to be adjusted, as the parts are affected by wear and changes in humidity, and will change from their proper adjustments. The regulation of a piano is dependant on the amount of use that it receives. Constant playing will settle the levelling of the keys, changing the responsiveness of the action to the keys, and creating a different feel or touch to the player. A piano in poor regulation is hard to play, and the tone (see voicing) is also affected. 

Piano voicing is ensuring that the tone of the piano is consistent from note to note. Achieving a balanced sound, whether it is bright, medium, or mellow, is the ultimate aim in piano voicing. Unlike tuning, which deals primarily with adjusting the tension of the strings, voicing deals with the piano hammers and their relationship to the strings. 

Voicing the hammers is dependant on the piano being in good regulation, with all the hammers hitting the strings evenly. Voicing is also dependant on the piano being in tune. Piano voicing changes as hammer felt changes, through playing, which flattens and grooves the felt, or aging, where the felt loses moisture and becomes hard and brittle.

Regulation & Voicing, like tuning are a part of ongoing piano service, and should be addressed with each visit by a technician to keep a piano sounding in top condition. 
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