Voicing a piano means making adjustments which change its tone. It is a different process than tuning, and this difference is important to understanding what people mean when they refer to tone. Tuning changes the pitch of the string, while voicing changes the quality of the sound it produces, or the tone.
Piano tone refers to how the piano sounds overall. It is a complex topic, but one commonly discussed aspect of tone is brightness vs. mellowness. The following audio clips are of the same song, Satin Doll by Duke Ellington, played the same way, but with different tonal qualities. One has a brighter tonal quality, while the other has a mellower tonal quality. Listen to them back to back to get a sense of the difference.
A bright piano produces more harmonics on the higher end of the spectrum, while a mellow piano produces more harmonics on the low end. For a breakdown of harmonics we have a separate post on the blog, here.
Achieving The Desired Tone
Making adjustments to the piano to achieve the tone the player wants is done through voicing. Pianos can be voiced by manipulating the strings or by manipulating the hammers. Voicing the strings involves making sure the strings are in the proper position to make the most efficient use of the energy from the hammer. Voicing the hammers involves shaping, softening, or hardening the hammers so that they produce a more desirable tone. It is more common to voice the hammers, so we’ll look at that aspect of the process.
One reason that voicing hammers is more common is that hammers become noticeably compacted over time, and eventually produce a very harsh, dissonant sound. The strings pound grooves into the hammers the more the piano is played, and the harder the grooves become, the brighter the piano begins to sound. The top of the hammer also becomes flattened, which will negatively affect the tone and make it harder to voice.
Piano technicians can compensate for this by voicing the hammers down, or making them sound more mellow. This is done by poking the hammer in specific places with a needle to soften it up, by filing the hammer, or by soaking the hammer in a liquid that is basically the equivalent of a fabric softener.
Sometimes, however, hammers have to be voiced up, to make them brighter. This is common with certain manufacturers, such as Steinway, who typically make mellower sounding pianos. In this case the technician will try to harden the hammer, most often by soaking it with a hammer-hardening solution (usually either plastic dissolved in acetone or lacquer mixed with lacquer thinner).
Even And Uneven Tone
Older or more used pianos frequently have certain hammers that are either brighter or mellower than others. A technician can make the tone of your piano sound more even by selecting the hammers that stand out and making them brighter or mellower as needed. This is a quick and cheap way to improve the tone of your piano. Voicing an entire piano takes much longer and costs more, but it is worth it if you want to make the whole instrument brighter or mellower.
Limitations Of Voicing
Manipulating the hammers and strings to change the tone of an instrument can’t compensate for design. For instance, smaller instruments produce more dissonant harmonics, so no matter what you do to the strings and hammers on a smaller piano, especially 5′ or shorter, it may always sound a little unpleasant.
Preferences In Tone
What a piano player wants to get out of voicing is highly subjective. It is entirely up to your personal taste, what music you like, and even the room that the piano is in, as a piano that is too bright in one room may have the perfect tonal quality for another.
Elton John definitely likes his piano on the brighter side:
While Bill Charlap seems to prefer a mellower piano:
It is worth noting that some manufacturers make brighter pianos than others. The two most obvious examples are Steinway and Yamaha. Yamaha tends to make a piano on the brighter side, and these pianos are not usually voiced up, as it would create a tone that is too harsh.
Steinway, on the other hand, tends to make a mellower sounding piano, which may need to be voiced up, especially in the treble section.
Voicing a piano is all about tone and, as such, is highly subjective to the taste of the piano player. This is most often done by shaping the hammer or making it harder or softer, but manipulating the strings so that they are in the right place can be helpful as well.
Brightness as opposed to mellowness is the easiest way to start thinking about piano tone and deciding when you want to get your piano voiced. It’s important, however, to remember that no amount of voicing can overcome the design of the instrument.