Posts tagged semi-tone
Pianos are stubborn! There are no two ways about it. If you pull their strings, they’ll pull back. In fact, it’s a little like a tug of war when tuning. The farther the piano has dropped in pitch (remember that there are thousands of pounds pulling whether you play the instrument or not), the more the piano is going to complain when you pull it back up to pitch. For example, there are 100 cents in a semi-tone. A cent is an increment of pitch. So if you pull strings 25 cents, quite often the piano will pull back 8 cents. Raise the pitch 15 degrees (or cents) and it will pull back 5 cents. Why is that? Most of that pull-back is from the soundboard responding to added pressure.
The following are some tuning fun free facts i’ve noticed in recent years:
1. Solid reputable pianos will fall about 3-5 cents per year. It makes sense then that a piano that hasn’t been tuned for three years will be out of pitch 9-15 cents.
2. Pianos will not stay perfectly in tune if they are out more than about 15 cents. Back to the tug-o-war… you tighten the strings and it will pull back. It is impossible to stabilize perfectly a piano on first tuning that is out more than 15 degrees.
3. It’s a good idea then to compensate for this loss of pitch. Let’s say that A440 is “0” and that the piano is 15 cents down in pitch (-15). I usually adjust my strobe to tune +5 and expect that the piano will then drop by that amount. Crossing fingers, the piano will end up at 0 after completion.
4. Pianos farther than 40 cents down and have strings that look old and rusty, expect possible string breakage.
5. When pianos are farther than 15 cents down, it doesn’t mean that the piano cannot be tuned, it simply means that it would be a good idea to do a ‘pitch raise’ first and then do a fine tuning. A pitch raise is a very fast tuning to bring the piano into the ballpark. Once the piano has settled somewhat to the new tension, it is then possible to tune it at which point, the piano should be stable.
6. Piano wire gauge is matched to the pitch of a note. Even though the wires may look all the same thickness, they’re not. And so when pitch has slidden, the piano also won’t sound optimal. Only when the instrument is matched for the pitch will the tone also follow. Pianos that are flat in pitch usually sound dull and lifeless.
Next time you have your tuner over, ask him/her (providing they have a strobe) how many cents your piano is ‘out’.
PS…you’ll look like you’re in the know