Why do pianos need tuning?

“If I move my piano to another room, does it need to be re-tuned?"

"My grandmother had a fine old upright that she never got tuned. Why does my piano need regular tuning?"

"Back home we always kept a jar of water in the bottom of the piano. Does this help keep the piano in tune?"

"How often does my piano need tuning?”

Piano technicians hear these questions every day. Tuning is the most frequent and important type of piano maintenance, but it’s often the least understood. Here we’ll look at why pianos go out of tune and how you can help yours stay in better tune between visits from your technician.

First, new pianos are a special case; their pitch drops quickly for the first few years as the new strings stretch and wood parts settle. It’s very important that a new piano be maintained at proper pitch (A-440) during this period, so the string tension and piano structure can reach stable equilibrium. Most manufacturers recommend three to four tunings the first year, and at least two annually after that.

Aside from this initial settling, seasonal change is the primary reason pianos go out of tune. To understand why, you must realize that the piano’s main acoustical structure, the soundboard, is made of wood (typically 3/8-inch thick Sitka spruce). And while the wooden soundboards produce a wonderful sound, they also react constantly to weather. As humidity goes up, a soundboard swells, increasing its crowned shape and stretching the piano’s strings to a higher pitch. During dry times, the soundboard flattens out, lowering tension on the strings and causing the pitch to drop.

Unfortunately, the strings don’t change pitch equally. Those near the soundboard’s edge move the least, and those near the center move the most. So, unless it’s in a hermetically sealed chamber, every piano is constantly going out of tune!

The good news is there are some simple things you can do to keep your piano sounding sweet and harmonious between regular service appointments. Although it’s impossible to prevent every minor variation in indoor climate, you can often improve conditions for your piano.

• Start by locating the piano away from direct sunlight, drafts, and heat sources. Excess heating causes extreme dryness, so try to keep the temperature moderate (below 70 degrees) during the winter heating season.

• Get a portable room humidifier, or install a central humidification system to combat winter dryness in climates with very cold, dry winters. A portable dehumidifier or a dehumidifier added to your air-conditioning system can remove excess moisture during hot, muggy summers.

• If controlling your home’s environment is impractical, or if you want the best protection possible, have a humidity control system installed inside your piano. These are very effective in controlling the climate within the instrument itself. Besides improving tuning stability, they help minimize the constant swelling and shrinking of your piano’s wooden parts. The critical part of such a system is the humidistat, a device that monitors the relative humidity within the piano and adds or removes moisture as needed. Jars of water, light bulbs, or other “home remedies” have no such control and can actually do more harm than good.

Used with permission of the Piano Technicians Guild