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Piano Tone Regulation - How beautiful piano tone is created
How Beautiful Piano Tone is Created
Many pianists don’t realize that beautiful piano tone does not simply appear after a piano has been fabricated. Whether it is a piano restoration or a new piano, when the strings are put on the new soundboard, and the new or rebuilt action has been installed in the piano, the piano’s tone is initially surprisingly nasty.
Beautiful tone has to be patiently coaxed out of a piano. This applies to any piano, whether it is a fine piano restoration or a new Steinway.
Why is this so?
Hammer striking string is a violent impact. In order for that impact to produce beautiful sound rather than chaotic noise, all of the piano’s systems and interactions must be precisely mated. It takes some doing to accomplish this.
Tone regulation is the process which allows me to find the optimal ways to mate the piano’s systems. Tone regulation transforms the initial tonal nastiness of a newly strung piano into beautiful sound. It is an art that a few select rebuilders really excel at. It is one of my specialties.
Tone Regulation: A Multi-Step Process
Tone regulation is a multi-step process. It includes:
- piano hammer voicing
- piano string voicing
- piano action regulation
Piano Hammer Voicing:
As the hammer accelerates to and strikes the string, it momentarily whacks a “lump” into the string, ie, the hammer momentarily deforms the resting string. Piano tone is defined by the shape of this initial string deformation. If you change the shape of this initial deformation, you change the piano’s tone.
Hammer voicing defines the shape of that initial “lump” by controlling the hammer’s internal resiliency.
Techniques used in hammer voicing include: steaming the hammer’s felt, applying hardening solutions to the whole hammer or targeted parts of it, inserting needles into parts of the hammer to create voids, adding or removing hammer weight, etc.
Piano String Voicing:
The piano string is voiced as well as the hammers.
Piano string is stiff taught wire. This wire encounters a series of obstacles placed between the tuning pin in the front of the piano and the final loop at the back of the instrument. As the wire passes through these obstacles it must bend around them in particular ways. If the bends are formed correctly and consistently, the string will vibrate with a waveform that is coherent, producing beautiful sustained tone. If the bends are not formed precisely the string will take on chaotic waveforms producing nasty tonal effects.
The string bends must be consistent throughout the piano. Further since there are three strings sounding for any one note, all the string bends for any one note must be carefully matched so that all three strings vibrate in the same coherent manner. As well, all three strings must be perfectly aligned with each other so that the hammer can strike all three strings at the same instant.
String voicing is performed on piano rebuilds and brand new instruments. It is also periodically performed during tone regulation service, concert prep, or when a piano has tone problems.
Piano Action Regulation:
The piano action refers to the keys and the complex series of levers which connect the keys to the hammers.
It might seem counterintuitive that the action’s keys and levers effect the tone of the piano, but the action has a major effect on piano tone.
How? Hammer acceleration.
As I mentioned above, the shape of the hammer/string deformation defines the way the string vibrates and therefore defines the quality of the tone. The speed at which the action accelerates the hammer to the strings has a major effect on how the hammer deforms the string.
The geometry built into the key and action levers effects the acceleration of the hammer. Independent of the pianist’s control, the overall leverage of the action accelerates the hammers at speeds consistent with that leverage. Different accelerations create different tone qualities.
Further the hammer does not strike the string in a perfect up/down motion. Rather it strikes the string in an up/down motion with some amount of side-to-side motion. The hammer’s side-to-side motion can create complex and inconsistent waveforms. Complex chaotic waveforms sound noisy and harsh.
Finally, all the hammers must strike the strings in a consistent manner. In order for this to happen, all of the thousands of parts in a piano action must be precisely calibrated so they behave consistently. A full 37 steps of calibrations must be performed in order for each lever in the system to behave in a consistent fashion.
Tone regulation is an art.
The finest piano rebuilders, those who love sound, know that piano restoration is about creating beautiful piano sound. They are sound artists; they sculpt sound. They know how important the tone regulation process is in creating beautiful sound. Any rebuilder’s piano restorations can be judged by the sound he has been able to sculpt into his pianos. The finest rebuilders know that achieving that sound is a matter of design and technique, rather than a matter of chance. They are totally committed to achieving beautiful tone.
Whether it is a fine restoration of a Steinway, Mason & Hamlin, Bosendorfer, Yamaha, Chickering, Knabe, Baldwin, Schimmel… any piano, tone regulation defines the tonal result. All these tone regulation procedures must be performed before any piano restoration can produce beautiful tone.