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I have an issue on my grand piano with many keys where an extra sound is heard. The extra sound is difficult do describe but can be heard in the YouTube video. The note is not clear; there is an extra muffled noise going on.



It's heard when playing the notes medium to loud. The piano is from 1929.
I have tried voicing the hammers with a voicing tool. I've also tried gently sanding the hammers with P60 grit sandpaper.

Please share any ideas or questions with me.

Thank you.

The dull thud is normal, the little high pitched tick tick tick, that may be the hammershank is loose. So during the cold months with the heater on as the wood loses moisture, if you don't have humidity control this can happen after a while. It has to be re-glued. Make sure you get all of them at once, because it's likely other hammer shanks have this to a degree as well.

The unisons on that note are way out of tune.

I definitely hear a woody sound. Can it be that the key is rubbing the neighbor key while pressed? Or the hammer itself is rubbing against the neighboring hammer. Since you voiced the hammer, you do know how to get the piano action out? Could you take a video of the action out and pressing that key? I think you will hear where the problem is more easily this way.

Thank you for the reply.

Is the hammer shank interface that needs to be glued shown in the below image where the hammer meets the long shank?

https://rennerusa.com/resources/grand-piano-action-guide/

Thank you for the reply.

I did a google search for "piano unison" and I'm not clear on its definition. It seems a unison is how two notes in different octaves are tuned to each other. How would you hear an out of tune unison if I'm only playing one note? Or is one string of this 3-stringed note just out of tune? If so, the piano got new strings and has only been tuned twice since then. It was tuned on January 20th so it has probably gotten out of tune since then.

Thanks again.

Unisons are the strings on the one note. Get it tuned.

Thanks, yeah, I'm planning to get it tuned soon.
Do you think it would be normal or expected for the tuning to get this bad in a 2 months 10 days (after having new strings)? Or is it possible that the pin block's quality is bad?

A little background: the new strings were installed around Jan 2020. The piano was delivered and tuned Feb 2020 right before Covid. There were so many issues with this piano at first and due to the risk of Covid we just ignored it for close to a year. We used a Yamaha M305 upright in the meantime.

New strings are not stable for a while. The number of tunings is more important than the time between tunings.

Thanks for the reply.

The other poster is correct that the problem is a high-pitched tick tick tick noise. I can't hear it when playing the key softly.

Here is a video I just made of the same key being pressed. I don't see or hear any issues with the action. (Also the hammer shank appears properly glued.)

I'd estimate that 30 keys make this sound.

Teflon bushings

Thanks for the reply.

Do you think the piano needs:
1) to have its teflon bushings lubricated,
2) have its teflon bushings replaced, or
3) have teflon bushings installed?

Where are bushings shown in this image?
https://rennerusa.com/resources/grand-piano-action-guide/

You can see one in the video. Look at the first shank by the action bracket, where it hinges. The white around the pin is the Teflon bearing. If they are loose, you can see them wiggle in the hole in the wood.

Another possibility is a loose drop screw. But a poor hammer glue joint sometimes will not show except for a click.

Are you in Berkeley? I know a Seaborg anagram when I see it!

You say you voiced some notes. You really shouldn't stick needles in your hammers until everything else is fixed, including a good tuning.

I'm no expert, but that's one thing I'm sure of.

Haha! A Seaborg anagram. Never heard that.
I went to U.C. Berkeley and graduated in '03. (I performed a Noon Concert there in 2001.)

Thanks for your message. I found the teflon bearing. It's 3mm in diameter and is inserted from the side (not the top). I don't think I can see whether the one is loose on keys that are causing problems because it's hard to see into the side of an action.

Just curious, if I hold a wooden block above the hammer and press the key, I don't hear anything unusual. Does that help with this investigation?

I'm hesitant to reglue the hammer glue joint because it won't budge and the glue bead looks in tact.

The previous technician did voicing before or after tuning it last time (Jan 20th). He came back two weeks later to do more voicing because his initial voicing was insufficient. It was still way too bright after his second pass so I bought my own voicing tool and voicing block and it's significantly better now.

Apparently Glenn Seaborg learned about the anagram from his son, who talked at the 100th birthday celebration. My father had Glenn Seaborg as a lab assistant in one of his chemistry classes back in the '30s. I was there in the '70s. I used to go to the noon concerts, but not so often now.

If there is a click, it could be a Teflon bushing. You would have to take the shank out of the action to see the looseness. Early bushings were more problematic, but since yours are not original, you cannot tell just from looking. The later bushings have ridges on them that conform to moisture-related deformation of the wood. Your tech may or may not know about that.

Really cool to learn about Seaborg! I just read part of his wikipedia page.

So now I've learned that removing the shank is very easy. I did it and took a video. Please watch and let me know what you think. It appears the teflon bushing is not loose. I did notice the shank was biased toward one side. I moved it to the middle so there is an air gap between it and the teflon bushing on each side. Hope that makes sense.

Any other thoughts? Thank you so much for your help so far.

Another thing that can click is the joint in the arm on the jack, if that comes unglued. Or the sostenuto tab hitting the sostenuto bar, or a loose key stop or damper stop rail. Good techs have to think of a lot of possibilities, and even then, sometimes something else pops up.

Ok, good to know.

I thought of an idea now that I know how to disassemble the hammer shank assembly.
Maybe I should swap a known bad hammer shank assembly with a neighboring known good hammer shank assembly to see if the problem follows the hammer shank. That will tell me hopefully whether the problem is in the hammer shank assembly or elsewhere.

I'll try that and then report back.