Piano String Basics And How They Affect Piano Tuning
Piano tuning may sometimes include maintenance for the piano's mechanism (such as worn hammers and felt pads), but it mainly involves the piano's strings. The strings are the part of the instrument that controls the pitch of each note, so the strings are the parts that need to be adjusted to ensure notes are in tune.
Here are some of the basics of how strings work and what that means for piano tuning.
Piano strings vibrate to form audible pitches
A piano string has to vibrate at a certain speed to create the right pitch. The longer a string is, the lower the note will be (this is why the strings for the lower range of the piano are much longer). However, if a string loosens slightly or stretches slightly, its length effectively becomes a tiny bit longer, making its note sound a tiny bit flatter.
Since loosening and stretching are both completely normal responses to being stretched as tight as piano strings are, going flat is fairly common. So a tuner often has to boost string tension slightly to get the string back into tune.
Piano strings often work in twos or threes
To make things more complicated, a piano doesn't just have one string per note. Many notes will have two or three strings of the same length and tension together so that striking a key causes two or three strings of the same pitch to sound. As you can imagine, if one string is a bit flat and the other doesn't, striking the note will cause it to sound out of tune with itself.
What this means is that a piano tuner not only has to do more work (since there are more strings to tune), but that they have to tune these strings very precisely in order to achieve a good sound.
Piano strings often vibrate in sympathy
Musical notes are mathematically related. If you have two strings and one is twice the length of the other, one of the frequencies of the longer string's vibration will be the exact length of the shorter string. As the sound waves travel through the air, the mathematical relationship can cause the shorter string to vibrate as well in what's called sympathetic vibration.
What this means for piano tuning is that a tuner has to carefully isolate each note while tuning. They may have to use special mutes (muffling tools) to keep all the other strings from ringing in sympathy and making the pitch of the current string harder to listen to.
These are just some of the basics of how piano strings behave and what that means for piano tuners during a tuning job. As you can see, piano tuners need to have not only the right equipment but also the right training and experience to tune a piano correctly and efficiently.
Contact a local piano tuning service to learn more.