I recently bought a 2nd-hand upright piano and had it tuned after a couple of weeks. The tuner (who came well recommended) says he got it up to concert pitch.

However I noticed one key in particular - about an octave and a half about middle C - causes a nasty whining buzz. It's reminiscent of a dentist drill almost. The note itself seems in tune and opening the lid doesn't make it stop (I thought it could be a buzz).

What could cause this? It's maybe only noticeable to the player but it's a key that gets a lot of use. Could it be a tiny issue in the tuning between the strings on that key - it seems too high-frequency to me personally? Or does it suggest something is loose?

The tuner man did say that it's really only when he does a 2nd tuning on a piano he can see which strings have particular issues (which pegs slip, etc) and I'm loath to get him out just for this one issue.

  • What a great opportunity to play in a different key!!!
    – Tim
    Feb 26, 2015 at 12:04
  • Ha, sadly it's one that is used in many keys and I'm only a beginner so transposing on the fly might be a bit of a struggle :)
    – Mr. Boy
    Feb 26, 2015 at 12:39

5 Answers 5


There's a possibility of something touching the string; either some foreign body dropped in there & wedged against it, or even part of the mechanism touching the string.

I'd recommend visual inspection first.
Grab a torch, get the front off & go have a look.

Very gently wiping down the length of the string with a lint-free cloth may help - be extremely careful as you go past the dampers not to knock anything.

  • By torch I assume you mean what I call a flashlight and not a flaming stick ;)
    – Max
    May 3, 2020 at 11:46
  • Yeah. We don't do 'flashlights' here. Same word covers both.
    – Tetsujin
    May 3, 2020 at 11:47

This type of noise can be hard to track down, because it might not be coming from the piano at all. It could be almost anything in the room resonating at the pitch of the note. If your piano tuner changed the pitch, that's enough reason why the problem only started after the tuning.

it's very hard to hear the direction the sound is really coming from, and if you are playing the piano, your brain will assume it is coming from the instrument. Get one person to keep playing the note while somebody else walks around the room and checks out every hard object that might be rattling, before you assume it's coming from the piano. When you get close to the source (i.e. your head is only a foot away from it) it should be apparent where the sounds is really coming from.

Any glass, ceramic, metal, or similar object in the room (including things like glass panels in the door) is a possible cause. The weirdest one that I've encountered was a light bulb!

  • Interesting point. It does sound like the kind of noise you get when a cup is sitting slightly crooked on a glass table and the TV/washing machine causes it to rattle at a very high pitch. Worth some investigation.
    – Mr. Boy
    Feb 27, 2015 at 8:14

Something rattling or resonating. Or just a bad string. It happens.

Did you watch the piano tuner at work? Remember how he used felt or rubber wedges to damp two of the three strings of each note so he could concentrate on tuning each one seperately? You could do the same to pin the noise down to one string.


You need to let the piano settle into its new environment before a second tuning. If the first tuning got it into concert pitch, it was already in tune from its last owner (my spinet took two tunings, 6 months apart to get it up to pitch after being neglected for 8 years)

If nothing is touching the strings as others have suggested, a miniscule difference in tunings of the strings could cause a discordant sound as you suspect. You may need to put up with it until the instrument settles and you can have your second tuning.


If you don't notice a foreign object upon visual inspection, the pin that holds the string in place may have come loose, often this causes a muffled or tinny sound. Your piano tuner should be able to repair it by hammering the pin more firmly in place.

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