The Technical Craft Of Piano Tuning


Working Toward A Controlled Environment

Although the piano is very strong structurally, the slightest variation in string tension will cause the pitches of the strings to change. Variations in humidity and temperature are common causes for these changes. While this might not hurt the piano's integrity, it ruins the sound quality.

To illustrate this, imagine two identical pianos, but two completely different environments within which the pianos reside. One piano is subjected to a wide range of temperatures, such as in a church with no plumbing in the sanctuary. During the frigid months of winter, since there are no water pipes to freeze and burst, the heat is regularly turned off during the week when the parishioners are away. The result is cold interior temperatures that begin to approach the winter outside. But on Sunday, for the comfort of those attending service, the heat is turned up to a warm, comfortable seventy-two degrees. Similarly, in the hot, muggy months of summer, since the sanctuary is unoccupied during the week, the air conditioning is turned off. But again, on Sunday, the temperature is cooled and dried for those few hours when the congregation gathers.

Although perhaps more drastic in degree than what a home piano endures, the situation illustrates the extent to which erratic fluctuations in relative humidity and temperature will work against the piano's ability to stay in tune.

In contrast, imagine a piano residing inside a newly constructed home made with the best insulation where the climate is meticulously controlled. Because drastic changes in humidity and temperature are avoided, the soundboard, cast iron plate, and strings change very little. Therefore, tension modulations are minimized. The result is an environment that contributes to the piano's ability to stay in tune.

Truly, the ideal environment for a piano is one within which the relative humidity and temperature are kept constant and at a proper level. Every piano's home fits into the spectrum just described. Exactly where your piano lies will affect how often it needs to be tuned.

The Tuner Approaches The Piano Each According To Its Needs

When the tuner begins the work it will be determined how out of tune the piano is. If it has been in a sheltered environment and given regular tunings it will be closer to the goal of being in tune than a piano that, for example, has been stored in a garage for years and then brought into the house for use. With such cases, very often the piano needs what we call a pitch raise or pitch adjustment. The reason why a pitch raise is in order is because all the strings have been stretched and relaxed so many times that most of them are far removed from what their actual tensions are supposed to be. This necessary adjustment is actually an extra step that needs to be done before a proper tuning can be accomplished. If such is the case with your piano, this stage of the tuning is so crude that it is difficult to hope for more than simply getting the tuning "into the ballpark." The strings will resist this change but eventually they will settle into the new tension. Once a few months have passed, the piano can be tuned again starting from a much better place. The result will be a much more refined tuning. As a metaphor, imagine the art of modeling clay; the farther along from the lump stage you are, the more detail and refinement you are able to put into the work.

As mentioned above, controlling the atmosphere around the piano is probably the most important part of maintaining the tuning once it is done. If this can be achieved by controlling the room environment year round, all the better. Often people install climate control systems specifically designed for the piano. A system of humidifiers and de-humidifiers buffer the changes in humidity, which is very helpful. But these systems need to be maintained and the room temperature still needs to be as consistently even as possible. If you can't afford a climate control system, often you can buffer the changes by simply having potted plants in the room that are watered regularly (but never put potted plants or vases with water on the piano itself). This approach isn't as good as modern technology but it's better than nothing. Anything you can do to control the environment around the piano will help. Another element to avoid is direct sunlight, which over time will degrade your piano's finish, as well as affect it's temperature, warming it up during the day and cooling it at night. An exception to the environmental rule is when the piano has brand new strings. The stretching of the new strings will eclipse any temperature or humidity changes until they are broken in.

How The Piano Tuner Conducts The Process Of Tuning

The piano tuner begins by opening up the piano to gain access to the tuning pins. This may involve removing several parts of the piano cabinet, especially with upright piano models. So having a safe place to put those parts is helpful. Also removing objects from the top of the piano in advance of the tuner's arrival, such as photos or books, will help get the job started. Once the piano is opened up the tuner can determine any preliminary work that might be needed, such as cleaning, tightening screws, spacing hammers, or other action adjustments.

If everything is in order, the tuner can then begin the tuning process. If the piano has been out of service for a few years, or exposed to erratic and/or drastic environmental changes, the piano may require the pitch raise procedure mentioned above. The process begins in the center region of the piano, working toward the treble and then toward the bass. At this time the technician adjusts all the strings, pulling up their tension quickly without really fine tuning them. The goal is to get the tension close to where it would be if the piano had been receiving service regularly.

Once the pitch adjustment has been accomplished, or if this step isn't required, then the technician can begin fine tuning the piano. While listening to the sound of the strings, they will be adjusted to achieve the most pleasing sound. Sometimes this is done completely by closely listening to intervals, which is the relationship of two different notes. This is most efficient when the piano is only slightly out of tune. Analogous to polishing glass that is already fairly clean, what the technician does is bring the pitch back into focus. If the piano is a little more out of tune than that, often times an electronic tuning aid (ETA) is used to get the tuning very close fairly quickly. At that point, the tuning can be finished aurally, or "by ear." In this way, ETAs are efficient in helping get the job done faster, but the last word about the tuning is in how it actually sounds to the tuner when examining the interval relationships.

Different intervals have different characteristics. Unisons have no beats, octaves might have a slight beat but it should be imperceptible. Fourths and fifths are allowed a slow, rolling beat, about one beat every two or three seconds, and thirds and sixths have about six to seven beats per second in the middle section of the keyboard, getting faster as they ascend and slower descending toward the bass.

The string tension is adjusted by using a wrench-like tool technicians call a tuning hammer. The technician uses the tuning hammer to turn each pin where one end of the string is attached. The pin itself is driven into a piece of maple called the pinblock, and is held in place by friction. The more radically these pins need to be turned, the sooner the friction holding the pin in place breaks down. This wear isn't something that happens overnight, but usually after many years, although the speed and degree of wear can be forestalled by regularly scheduled tunings and by a climate controlled environment.

Not only is the pinblock vulnerable, but extreme environmental changes also affect the soundboard, which is the very thin sheet of spruce wood that amplifies the sound of the strings. Exposure to pronounced seasonal changes over the years can stress the soundboard causing it to crack. At best this is just unsightly, but at worst the cracks can buzz and distort the sound. Cracks in the soundboard also affect the piano's resale value because people naturally want a piano without flaws.

Certainly, if an experienced technician services a piano worthy of extended care, the technician will make recommendations to the client concerning regular maintenance. If the client takes heed and follows those recommendations, the result is likely to be a piano that will tune like new for decades longer than it would otherwise. Honest communication between the client and technician will help develop a working relationship that results in practical steps taken to achieve what is most important: a controlled environment, a regular schedule of tunings, as well as other important forms of conservation that could make all the difference between a piano becoming a cherished family heirloom or one in need of replacement.

Ask Your Professional Piano Technician What Needs To Be Done

When the piano tuner arrives you can ask for help on assessing your piano's environment. Perhaps your piano needs something as small as a light cover or piano scarf. Maybe it should be moved to a different spot in the room, or perhaps a climate control system is the solution. It might take a couple of tunings to make a definite determination of your piano's needs, but having your piano serviced regularly will definitely help you keep it at its best and enjoying it for many years to come.

Special Note

Many thanks to Robert Callaghan, RPT and resident piano technician at the University of Nevada, Reno, for input and discussion concerning this article. Before taking his current position at UNR, Mr. Callaghan was a valued employee at Sweeney Piano.

Who Tunes The Piano?

If you've ever been to a live symphony performance, you might have noticed that before the conductor walks on stage, the concertmaster -- usually the first violinist -- makes sure that all the instruments are individually tuned and in perfect pitch with each other. There is a protocol to this procedure: the concertmaster asks the first oboist to play what is known as a 'tuning A' (the A just above middle C set to a standard 440 cycles per second). Once the note is played, very quickly, the other woodwinds tune to the oboe, then the brass and strings tune to the woodwinds. But what about the piano? Who tunes the piano?

It is a rare case, indeed, for the pianist to be the one who also tunes the piano to be played. It's not surprising since a typical piano has considerably more strings and moving parts than any other instrument on the concert stage. In fact, there are so many factors involved in the process of tuning a piano, an entire profession surrounds the craft. And although you might find Web sites telling you how easy it is to learn how to tune your own piano, you'll also find as many sites warning against facing the learning curve on a piano that has any monetary or sentimental value whatsoever. Even if the basics are fairly straightforward and the background theory easy enough to understand, it takes years of serious dedication to become a master of the craft.

And so the pianist turns to the professional technician...

What Does It Mean To Be In Or Out Of Tune?

The piano is considered to be in tune when the sounds generated by the vibrating strings blend together creating a homogenous, resonant and pleasing sound. Analogous to the way three violins playing together sound louder than a single instrument, when the three strings of a unison are sounding at the exact same vibrations per second (vps), they combine and reinforce each other. Likewise, when other strings of the same note name are played together (one or two octaves higher or lower), if they are adjusted so that they reinforce and blend in with the initial note, the result is a clear, more sonorous sound that resonates as a single voice, much like the sound of an orchestra playing beautifully in tune.

This blending together of sound is what the piano tuner achieves by adjusting the tension of the strings. Most piano strings are in groups of three, all sounding exactly the same pitch. This is called a unison, from the Latin word "unisonus" meaning having the same sound. When one of the strings of a unison changes slightly in tension so that it vibrates at, say 439 vps instead of 440 vps like the other two of the group, it starts to work against the group. The result is a less resonant sound because the strings are now acting independently of each other instead of reinforcing one another. You can hear them go in and out of phase as one string's vibration is passed by the others. One moment they are together and blending, the next moment they are dissonant and discordant. This alternation between reinforcement and opposition can be heard as what tuners call "beats." A note having beats is an indication that the piano is out of tune.

You might be able to hear this yourself. Play one key at a time on the piano and try to hear how some note might have a pulsing sound to it, while another might not. Now try a key of the same note name but a couple of octaves higher or lower at the same time, and listen for beats. They can be really rapid, sometimes described as a "boing" or "twang," or they could be heard as very slow, sounding more like a swelling or a wave of sound rolling by. The degree to which the tuner can hear beats determines the extent to which the piano is out of tune. When there are many rapid beats in several notes, the piano loses its clarity and lacks a beautiful resonance. This is because the piano has so many strings working against each other. The over all sound quality can become so bad that some people claim it hurts their ears!