Voicing and Tone Adjustment
Because the tone of a piano changes as the felt hammers wear, periodic voicing and reshaping of the hammers is necessary so that your piano will have an even, full tone throughout the entire scale, and produce the widest possible dynamic range.
The action is the intricate system of levers, springs, and hammers connected to the keyboard. The complex system that causes a hammer to strike a string when you press a key is called the piano’s Action. When a piano leaves the factory, each of its parts is adjusted to a tolerance of a few thousandths of an inch. This process is called Action Regulation. Because the wood and felt parts of the action may change dimension due to humidity and wear, the action must be serviced occasionally to maintain its responsive qualities.