It's Tuning Time Again!

As the long autumn of 2011 drew to a chilly close, it was time to be thinking about piano care again. Traditionally, tuners suggested waiting until “furnace season” started before tuning pianos—and in 2011, that meant waiting almost until the start of winter.


Is that still a good strategy for timing your piano's tuning? What causes pianos to go out of tune in the first place? And is there any way to avoid that?


The number one cause of changes in tuning is changes in humidity. Control humidity and you control your piano's tuning. Before air conditioning became nearly universal, pianos in Iowa spent most of the year in a fairly humid environment—followed by a season of unrelenting dryness. It's a wonder that any of them survived!


Then again, pianos were constructed of solid wood lumber, and the entire instrument absorbed and evaporated environmental humidity at a fairly slow and steady rate.


Now, however, air conditioning (which works by drying the air) and central heating have created a much more stable—but drier—environment. And the majority of modern pianos include a significant amount of “engineered wood product”, rather than solid wood. Those materials don't absorb moisture the way wood does, so modern pianos have less ability to moderate change when their surroundings get dry.


In general, pianos and humans do their best at about 47% relative humidity. And that's hard to maintain with modern heating and cooling systems. Even if your furnace has a built-in humidifying system, keep a good hygrometer handy so you can really gauge the humidity levels in your house or studio. But you can also tell by paying attention: if you feel a cool breeze when someone walks by, the humidity is too low.


Why does it matter? Wood swells when humidity is high and shrinks when it's low. In a piano, the soundboard flexes when it swells, drawing the strings tighter and causing the piano to go sharp. It flattens out again as it dries out, allowing the strings to loosen and go flat.


That cycle of swelling and drying is hard on tuning pins—which can crush the wood that's meant to hold them tight, leaving them loose and unable to hold a tuning—as well as on bridge pins, which can be moved by tight strings, cracking the bridges and affecting both tuning and tone. Humidity changes can also crack the soundboard, loosen the soundboard ribs, and cause any number of action problems.


What to do? Talk to your piano technician about options for creating a stable environment for your piano. That could involve moving the piano to a better location, adding a humidifier to the room, or installing a Dampp-Chaser system, depending on your situation.


And if humidity shifts have already caused problems in the pin block, bridges, soundboard, or action, develop a treatment plan for stabilizing and repairing them. Your piano will stay in tune longer, and you will both be happier. Talk it over with your technician; you'll be glad you did.