Why Does My Piano Go Out of Tune?


We are told that Murphy’s Law is enjoys a universal reign–that if anything can go wrong, it will. And true to reputation, legions of evil forces always seem to be at work on your piano, wrenching it out of tune and adjustment, scratching and smudging its cabinet (and you thought the kids did that!), and filling its obvious and hidden places with dirt and dust.

On the other hand, remember that your piano technician benefits from all of this, so perhaps Murphy’s Law has some limits after all. With all of the above in mind, then, the purpose of this pamphlet is two-fold: to provide some basic information about your piano and its ability to stay in tune; and to give tips for keeping your instrument in tune as long as possible.

Your Piano’s Construction

Realize first that a piano is, in many ways, like a living, breathing organism. Its skeleton, or sub-structure, must support over 200 strings tightened to about 200 pounds each, a total of about nearly 20 tons. This is accomplished by the strength of three major components:


(1)  The backbraces, four to six large wood beams, are visible from the back of the piano. They are usually made of solid oak or maple, and mortised into the rest of the hardwood frame. Obviously, the heavier and more tightly constructed these braces and frame are, the better your piano will be able to stay in tune.

The Iron Plate

(2) The metal plate, the part many call “that big, gold harp,” is carefully screwed into the wood frame to give extra support. It is made of solid (usually cast) iron (a rather unbendable” metal), and may weigh from 200 to 600 pounds; thus, it is the heaviest part of your piano. Crack it, and in most cases, kiss your piano goodbye.

(3) The pinblock is tightly fitted and screwed to the back side of the upper edge of the plate.  It is a little over one inch thick , 4″ to 6″ wide, and runs the entire length of the piano. It is usually made of laminated maple (i.e., thin layers glued together, like plywood). Its job is to hold all 200-plus tuning pins, allowing them to be turned while being tuned, but holding them firm the rest of the time. Because it is laminated, it is resistent to cracking; yet because it is made of wood, it is somewhat vulnerable to drying out, which in turn enlarges its holes and releases its grip on the tuning pins. This is much less likely to happen in higher quality pianos because the block is made of better quality wood. 

Factors Affecting Piano Tuning

The three previously mentioned components–backbraces, plate, and pinblock–have the awesome responsibility of remaining firm despite a total pull of nearly 20 tons when all of the strings are tuned to pitch. In a perfect world, this may be a routine task, but remember that Murphy’s Law is in effect; therefore, pianos do not stay in tune, and the reasons they do not are the results of the following factors:

Internal Factors (i.e., the piano itself)

In new pianos, these include weaknesses in materials and/or workmanship (especially in braces, plate, or pinblock). Generally, the lower quality pianos are not as strong structurally and so are likely to go out of tune more quickly. Factors in older pianos include the above plus those problems that can develop with age, the most commmon being loose tuning pins.

External Factors

These are all of the outside forces–“the elements”–that, over time, cause even the best pianos to slip out of tune. Again, think of the piano as a living organism, changing or “breathing” along with seasonal changes in weather and the piano’s environment. During warm and humid weather, the piano absorbs moisture and expands; during dry or cool weather, it dries out and contracts. This cycle is most evident with the changing of the seasons, but it also occurs to a lesser degree with day-to-day changes such as weather, heating and cooling practices, and moving routines (common in schools and churches).

What Can I Do?

After hearing how all of the previous “unseen enemies” stage a never-ending onslaught aginst your piano, the fearful person may be tempted to simply give up. Not so, friend! You can do a number of things to help your piano at least stay in tune longer.

First, keep your piano in an environment that will protect it from harmful elements. The ideal is a perfectly temperature – and humidity – controlled room. But since most homes fall short of this ideal, try to avoid the following:

  1. Basements! As a rule, a piano in a basement for any length of time will develop rusty metal parts, weakened glue joints, peeling veneer, and cracks or ripples in its soundboard.
  2. Baseboards, wood stoves, or any direct heating source. Baseboards should be at least on a different wall from the piano’s; woodstoves are risky even in the same room. Both will cause your piano to dry out unevenly, thus affecting its overall stability.
  3. Irregular heating or cooling. This keeps your piano not sure whether to expand, contract, or do both at the same time. Keep things as even as possible.

Second, avoid needless abuse. Of course, this does not mean not playing the piano to preserve its tuning (like my grandfather, who “saved” his phonograph needle by not playing records). It does mean teaching children to play, not bang or smash. The technique may also help them when they learn to play someday. (If they reach virtuoso status, then they can bang until their fingers fall off.)

Third, and finally, keep your piano serviced regularly. The average piano, in fact, will go out of tune in two years to such an extent that it may take two or more tunings to get it back in tune. Thus, you pay the same but don’t get the pleasure or peace of mind that regular tunings will give you. Keep in mind that in most areas, having your piano tuned once a year will cost you only about 15 cents a day. Compared to keeping your car running, that’s a great deal.