Why, and how, do pianos go out of tune?

This article is a 3-5 minute read

The piano question I think I get asked the most, especially by new customers, is, "how often should I get my piano tuned?" This question leads me to think of another one, which is, why do pianos need tuned, anyway? What causes them to go out of tune in the first place?

The short answer, which may surprise some people, is humidity changes. In most people's homes, the humidity will shift drastically with the change in seasons. When fall turns to winter, your heater will kick on and pump out air that is more dry; when springtime comes around, the air conditioning will deliver cool air that is generally more humid. This is not even to mention the wild humidity changes that are going out outside; here in the KY-OH-WV tri-state area, the saying goes that if you don't like the weather, just wait a little bit and it will change. The Ohio and Big Sandy rivers add yet another layer of humidity complexity on top of this.

These big humidity changes are why most piano manufacturers recommend having your piano tuned every six months. This is very nice, and I love when people tell me to come back semi-annually. Some organizations, like the Paramount Arts Center, have me tune their piano right before a performance. I’ve tuned the same piano three or four times in the span of a month before in these situations.

However, I understand that this can be out of reach for some. We all lead busy lives, and sometimes multiple piano tunings in one year just isn’t in the budget. This is why I recommend to most people to have their piano tuned at least once a year. Most of my customers find that this is a good time interval, and it’s actually when the majority of people will first start to notice their piano actually sounding out of tune. Plus, the yearly checkup is a good way to make sure that your piano is playing correctly, and for me to make sure that any issues that might be cropping up get nipped in the bud before they go from being issues to problems.

So there you go. Pianos go out of tune because of humidity changes. But what exactly is it about changes in the humidity that make pianos go out of tune in the first place? Let’s get technical.

To understand how this happens, it’s important to know a few things about how pianos are built first. A piano’s sound comes from vibrations in its strings. Each string (there are around 220-250 in each piano) is attached to the piano in a way that it puts downward pressure on a wooden piece called the bridge. This wooden piece connects the string to the large, flat piece of wood along the back/bottom of the piano, called the soundboard. This piece acts as a “bridge” for the sound to travel from the string to the soundboard, hence the name. The soundboard, being a much larger piece of wood, then vibrates and amplifies the sound so it can be heard from far away.

Notice that all of these pieces, the bridge and the soundboard, are made of wood. This is important mainly because wood is porous. It’s not solid like steel is, but is full of little holes, nooks and crannies, and other imperfections. If you’ve ever dealt with firewood, you know that wood can hold a lot of water, even if it looks dry, and it needs to be dried out before it will burn.

This porousness is the main cause of pianos going out of tune. Humidity changes cause the amount of water vapor in the air to change. This water vapor, over time, will “soak” into the wood. If the humidity goes up, the wood will expand, since there’s more water.

When the humidity goes down, the opposite happens.

This is important because when the wooden bridge and soundboard expand due to higher humidity, they will actually push upward on the string, increasing the amount of tension in the string, which in turn makes the string sound higher in pitch. The opposite is true as well; when the humidity goes down, the amount of water in the air, bridge, and soundboard will decrease, which will cause the wood to shrink, the amount of pressure to decrease, and in turn, the amount of tension in the string will decrease.

Let this process happen over and over in the course of a year, and congratulations: you now have a piano that is out of tune!

Thus, it is a really good idea for everyone to have their piano tuned at least once a year. These humidity changes cannot be completely stopped, considering the vast majority of us are not capable of creating an environment that has totally stable humidity year-round.

Installing a Dampp-Chaser Piano Life Saver system can certainly help, and can increase the amount of time you go between tunings. You will still need to have your piano tuned regularly, but the Dampp-Chaser can help to preserve your piano’s health and tuning by stabilizing the humidity around the piano.

Looking to have your piano tuned?

I would be glad to help you! Feel free to contact me or schedule online.