You’ve been told to have your piano tuned twice and maybe once a year, but have you ever wondered WHY it goes out of tune? The answer is not that simple, but hopefully I can help you understand your piano a little better.
The first thing to know is that the standard pitch of musical performances everywhere is 440hz. This means that the strings of the A above middle C vibrate 440 cycles per second. This standardization ensures that the whole orchestra is tuned the same.
HUMIDITY: So let’s get to when it’s out of tune. Some of the strings on a piano measure only a couple inches, and some a couple feet long. The strings cross a wooden bridge, and the bridge sits on the soundboard. The soundboard is a large panel of wood, that is made up of long narrow planks of wood. I’ll say, for instance, that the strings of F3 are 1120mm when the piano is in a room with 40% relative humidity. In the winter, when your heat is on, the humidity is reduced. When the air dries, the wood of the piano releases moisture and shrinks. When this happens, the soundboard gets smaller, and the vibrating section of F3 gets shorter, reducing the distance to 1119.87mm. This means the strings aren’t as tight, and the pitch reduces. Since not all of the strings are the same length, this happens unevenly, and there you are with your piano out of tune. Even if you aren’t using your piano, it will still go out of tune.
PLAYING: So, we’ve discussed humidity changes. The next reason your piano may be out of tune is if it is played heavily. Institutions have the highest quality pianos because they need to withstain around 12 hours of practice per day. That’s over 3,000 hours per year! A piano played this frequently and heavily will go out of tune to itself as the strings have not been settled evenly. Eventually, even pianos played this much settle in and go out of tune mostly due to changes in humidity. Most homes don’t have this problem.
TUNING TECHNIQUE: My last point is about improper technique. The technique a piano tuner uses is hugely important to the stability of the tuning. When the string is tightened, and the tuning pin is turned, the pin needs to be set in a certain way, or else it will drift back out of tune. I can’t share how to do this, but I can say that it comes with lots and lots of experience. I tuned pianos while at school and for a firm, and in the beginning, lots of my tunings didn’t last for that long. Within 3 years I had finally tuned around 1,000 pianos, but they were all different and I didn’t really learn from my own work. When I finally started working for a dealer, I got to tune the same pianos every few months and analyzed the work I did. I understood where my technique needed improvement, and worked towards a more stable tuning. Now, I tune around 1,000 instruments each year, and sometimes I get to tune 5 or more of the same model in a row. Since this brand and model (Yamaha U1) is so consistant when it is taken out of the box, I collect and analyze data that allows me to tune it quickly, accurately, and for stability.
So, in the end, if your home is a constant temperature and humidity, you may only tune your piano once a year. If the environment is unstable, and changes drastically with each season, you should have your piano tuned twice a year or more! No matter what, make sure you use a technician with good credentials and ask him or her to explain to you why your piano is out of tune, and have them recommend a tuning schedule that fits with your needs and budget.