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[This post is based on an essay titled “Why Does A Piano Go Out Of Tune”, written by William Braid White, Mus. D., in the early twentieth century and later included as an appendix in the fifth edition of his book Piano Tuning and the Allied Arts
For starters, it is necessary to understand that a piano has about 230 strings stretched at an average tension of one-hundred fifty to two hundred pounds each. The total stress on the wood frame and cast iron plate is between eighteen and twenty tons. This stress varies over time. The steel wire used in piano strings is highly elastic, tightening and loosening based on temperature shifts, although somewhat less so as the piano ages. The wood in the frame, pin block, and sound board swell and loosen as the humidity rises and falls through the year. Granted, these variations are less extreme in today’s highly insulated, tightly sealed houses with central heat and air (especially temperature), but they do still happen. And when the frame and board swell from humidity then dry out, or the piano strings tighten up from heat then loosen as they cool, the strings end up looser than they were when the process started, and the pitch drops. This process is ongoing, and continuous.
“Every change of a degree in temperature, or of one-tenth of an inch in a barometer, has its effect. The soundboard of the piano, then, is always slowly rising and falling through short distances, and constantly, therefore, suffering variations in its ability to hold the strings up to proper pitch. “(Piano Tuning & the Allied Arts, p.223)
So how often should I get my piano tuned? Dr. White recommended four tunings per year for the average layman, but if the piano is in a modern home in a moderate climate with good insulation and central heat and air, I believe that two to three tunings should suffice, mostly because the average human ear has difficulty discerning intonation more precisely than that. Just keep in mind that the longer a piano goes without tuning, the further out it will be.
Although Dr. White’s essay is approximately a hundred years old, the science behind it is still sound. So is his closing statement:
If you enjoyed this post, make sure you subscribe to my RSS feed!“To pay a lot of money for a fine piano and then allow it to go to ruin for lack of expert care is not merely aesthetically wrong- it is bad business.” (op.cit.,p.225)
