Humidity control is essential to helping to prolong the piano tuning, Address Piano Care can install a Dampp Chaser humidity control system to help remedy humidity fluctuations. Call for a free quote.
HOW THE DRY HEAT OF YOUR FURNACE MAKES YOUR PIANO GO FLAT
Diagram of the side view of
a "vertical" or "upright" piano soundboard
(greatly exaggerated).
The sample on the left shows the bow or "crown" in a soundboard (greatly exaggerated). In the winter, the furnace dries out the soundboard. The sample on the right shows the soundboard dried-out and contracted. It is no longer pushing as hard on the string, so the string grows flatter (again, greatly exaggerated).
WHY THE STRINGS DIRECTLY ABOVE THE BASS SECTION GO THE SHARPEST (OR FLATTEST) WITH HUMIDITY CHANGES
The middle of the soundboard is not glued down like the perimeter. Therefore, it "floats" the most. When moisture permeates the soundboard, it will swell up (on a grand piano). This puts more tension on the strings, causing them to go sharper. The middle strings go the sharpest. Since the bass strings have more tension in the first place, the soundboard cannot force them to go as sharp. Also, the bass bridge is attached nearer to the perimeter of the soundboard, which is not as flexible.
