Questions & Answers

Frequently Asked Questions About Piano Tuning

Why do pianos go out of tune?
Humidity changes are the main cause of pianos going out of tune.  The strings are mounted on a wooden soundboard that absorbs moisture and expands during humid weather, and shrinks during dry weather.  This stretches and relaxes the strings, changing their pitches and making the piano sound out of tune.  Also, the action of the hammers hitting the strings throws them out of tune.
How soon after moving should I have it tuned?
Wait three to four weeks after moving for the most stable tuning.
How often should I have my piano tuned?
Pianos in the northeast usually need to be tuned twice a year.  Pianos typically go out of tune when heaters are turned on in the fall and off in the spring, when there are dramatic humidity changes.  All of the pianos strings are attached to a wooden soundboard, and humidity changes make the board shrink or expand.  This shrinking and expanding causes the strings to go out of tune.
Ideally, pianos should be tuned at least once a year.  If a piano has not been tuned in more than a year, it takes longer to tune, and the tuning is not as stable.  Piano manufacturers recommend tuning every six months because that’s how long most pianos can hold a tuning.  There are exceptions to this, notably the Baldwin Acrosonic.  Some Acrosonics can hold a tuning for three years, because the tuning pins are very tight and it is a high-quality instrument.
Is there anything I can do to prepare for a tuning?
The tuning pins need to be accessible, so all objects should be removed from the piano.  Good lighting and a quiet environment are helpful.  In most upright pianos, the tuner will prop up the top and remove the front board for access to the tuning pins; grand pianos will be opened and the music desk removed.
How are pianos tuned?
Each piano string is attached to a pin mounted in the soundboard.  Some notes have two or three strings and each must be tuned.  A tuning lever is used to adjust the pitches up or down.
What can I do to maintain my piano?
Just play the entire keyboard on a regular basis to keep the action parts working.  Lack of playing makes piano actions degrade over time and is the main cause of sticking keys.  The highest and lowest notes don’t get played very much, so try to play a simple exercise on those notes on a regular basis.
Should I air-condition my piano room during the summer?
If possible, yes.  Reducing humidity swings will help keep your piano in tune longer.  It’s best to have your piano placed away from heating vents for the same reason.
How long does it take to properly tune a piano?
It can take 2-3 hours because most pianos have over 220 strings and every string must be tuned individually.  If a piano is very out of tune or needs a pitch raise, a second tuning is sometimes required to achieve tuning stability.

What are False Beats?

Old piano strings degrade over time, becoming brittle.  When you pluck a piano string, it makes sound by vibrating side-to-side.  It also has waves or pulses of vibration that travel from one end of the string to the other end, and back again.  These end-to-end vibrations are very noticeable in old strings, and they are called False Beats.  When two waves of false beats meet while traveling along the string, that phenomena is known as Wave Interference.  It interferes with the sound of a string, and it interferes with piano tuning meters.  There are two types of Wave Interference: Constructive Interference, which increases the sound volume, and Destructive Interference, which causes a decrease in the sound volume or total silence.  We recently tuned a two-string note on a 1910 upright piano, and the false beats in the two strings interacted in a way that caused the perfectly tuned note to go in and out of total silence repeatedly when you played it.  Amazingly, the sound waves were totally cancelling each other out.

What’s a Pitch Raise?
It’s a preliminary rough tuning of the entire keyboard to bring strings to their correct tension levels in a piano that is very out of tune or needs to be brought up to concert pitch.  This ensures that the final tuning will be stable.
What is Inharmonicity, and How Does Stretch Tuning Compensate For It?

An ideal piano string would produce upper harmonics (or overtones) of the main note that are all in tune with that main note.  However, real piano strings are very thick and stiff.  This makes the upper harmonics sharper than theory would predict.  This is called Inharmonicity.

We perceive the sharp upper harmonics as the actual pitch of the note. Therefore, a piano must be tuned to those sharp harmonics.

This would be fine, except that inharmonicity varies across the entire keyboard.

Since the shorter piano strings have a higher and higher inharmonicity as one goes up in pitch, we stretch the tuning sharp as we go up to compensate for this.

If one were to tune a piano without stretching the octaves, the harmonics of the low bass notes would clash noticeably with the harmonics of higher keys. To make the thick low bass strings sound in tune with the very high treble notes, the whole piano tuning must be stretched by making the octaves slightly wider than pure. This means that the notes above the starting pitch (F-3) will all be a slight but precise amount sharp, and the notes lower than the starting pitch will be slightly flatter. This is called a Stretched Tuning.

O.L. Railsback performed detailed experiments on stretch tuning in 1938, and published the Railsback Curve graph.  See the graph at this link: 

Top of the line electronic piano tuning devices, such as the Sanderson AccuTuner, can analyze the inharmonicity of individual piano strings to mathematically calculate an ideal stretch tuning.
The effect is to bring out a beautiful, unified voice from the instrument.  For inharmonicity measurements, the Accu-Tuner is superior to any other tuning instrument.
Why Pianos are Tuned in Equal Temperament
The term Temperament refers to the method used to tune pianos: we ‘temper’, or adjust, the interval between each note in a scale to make them sound evenly spaced.
Modern tuners always utilize the ‘Equal Temperament’ system for tuning pianos.  However, musicians did not always know about Equal Temperament.  In the past, keyboard instruments were tuned in various temperaments depending upon which key they were played in.  Notes that were not in that key would sound out of tune.
Equal Temperament was developed by mathematicians in both China and Europe in the 1500′s.
The development of Equal Temperament enabled composers to vary the key within one piece of music, taking advantage of the fact that the new temperament made it possible to sound good in all of the keys.
Bach’s famous composition, ‘The Well-Tempered Clavier’ takes full advantage of the breakthrough, showing off every single key in one piece of music.
Before the development of Equal Temperament, such a composition would not have been possible, as any given keyboard instrument would have only sounded in tune in a limited number of keys.
A simple arithmetic sequence of intervals would not sound evenly-spaced, and would not permit transposition to different keys.