Tuning Instability

In speaking to our customers about what causes a piano to go out of tune, the most common subject is the weather. A change in temperature will have little or no effect on the tune of the instrument except that most temperature changes are directly coupled to a change in humidity. Humidity change is the major factor when pianos are tuned two or more times a year.

The next most common factor is string stretch. It takes very little stretch, as we all well know from what a new string does, to make a piano sound horrid. Several years of tunings are needed to get all the stretch out of new strings. The newer pianos seem to go out because of settling of the structure as well as the stretch of the strings, but I have no proof of that.

Time itself, with the changes of weather, string stretch and structure, all cause the tuning to slide downward.

Hard playing and especially hard hammers will knock out the tuning of even the best tuner and the best piano.

One factor that seems to be rather neglected is the degree of sensitivity of the client. Some pianists are on the phone the instant the piano thinks about going out of tune, others can let the instrument go for ten years and not know the difference.

After the piano is settled in and the weather, stretch, age, time and customer demands are compensated for any real problems of the instrument itself can be considered.

One common cause of tuning instability is pinblock-back separation, where the pinblock is being pulled away from the back posts of uprights by the tension of the strings. This is most easily spotted by looking at the top of the assembly or from the bottom of the block. When the sides begin to separate from the back a weak piano plate and back can flex more than planned by the designers; tapping with the knuckles along the side will produce a hollow sound where the glue has failed.

A good number of pianos were produced with aluminium / magnesium plates that over extended periods do not have the rigidity and stamina of cast iron. This is a chronic problem without any real solution for that instrument.

When the smaller pianos were in their developmental stages, many of their unique problems were yet to be solved. One of which was determining the minimum weight and the structural rigidity for long-term integrity. Some of these early instruments tend to be ...

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