Voicing

The piano sound is produced by a felt-covered “hammer” striking the strings. Every time the hammer hits the string, fibers in the wool are compacted which over time makes the felt hard. Hard felt produces more and higher-pitched harmonics. Also, fibers of the felt are broken and worn away which leaves grooves in the hammers where the hammer comes in contact with the strings. As these grooves grow deeper and longer, the tone becomes less like the clear tone of a bell and more like the thud of a drum. Correcting these changes is called voicing.

Reshaping a hammer to remove grooves and the flat shape that contacts the strings is accomplished by filing away felt to reveal fresh felt and restoring the original shape of the hammer. This makes it possible to restore a clear and pleasant tone to the piano. There is a limit to hammer filing. Eventually it is necessary to start with a new set of hammers. That, however, is usually after many years of use. Good maintenance means regular filing in small increments. Allowing the hammers to become deeply grooved and flat could mean filing is less satisfactory or even impossible.

With the hammer shape restored, manipulating the fibers within the hammer can then be accomplished. Using a variety of technics the compacted fibers deep within the core of the hammer can be softened and a measure of the original resilience of the felt restored. Some hammers, particularly those manufactured in Asia, have chemical additives. Over time and with use, these hammers can become extremely dense and hard which produces a tone equally dense and hard. Overly bright, even harsh. Good voicing can bring the sound of a too-bright piano to a warm, pleasant tone that makes playing and listening to the piano enjoyable and musical.

The opposite of too bright can also be a problem. Occurring more rarely but certainly possible is a set of hammers that does not have enough support or firmness in the right places and the tone is weak, mushy, muted, or unfocused. In most cases this can be corrected as well.

Voicing is an important part of good and regular piano maintenance. To achieve an even and musical voice throughout the entire range of the piano, the piano must be in good regulation and voicing attended to regularly. As with nearly all procedures in piano maintenance, everything is progress toward a goal. Perfection is elusive but over time and with persistence, we can get close.