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Dear all,

here's a question to the voicing experts from someone who tried to "improve" his instrument himself.

Short version:

Is it normal that extremely small changes of hammer felts at the strike point can cause extreme temporary clanking of single notes/unisons?

Long version:

I have been playing on a used grand now for a while. It was tuned a few days ago and since the sound changed a bit for the worse I took out the action and looked at the hammer felts. They only have slight indentations i.e string marks, yet there was some "dirt" at the strike point of all of them.

Being aware of the sensitivity of the sound on the shape of the strike point and the whole hammer felt as such, I decided to very slightly try to clean these areas. I started with one note, checked that it did not alter the sound in a bad manner, and then did the whole range using the fine grained side of a paper nail file applying virtual no pressure at all in order to prevent any relevant changes to the overal shape, in particular the strike point.

Yet, putting the action back into the instrument I experienced a horrible clanking sound from quite a number of notes, in bass, tenor and treble. I was shocked and thought I'd done major damage. I checked if the hammer felts matched the strings evenly in each unison and that was indeed (still) the case. Yet, silencing out two strings resulted in non-clanking sounds of the remaining, corroborating my suspicion that the strings weren't hit at the same instant. Not knowing what to do I gave up, closed the instrument and started playing a bit. Then,upon putting the instrument back together the clanking sound disappeared and I thought it might have been some loose screws sitting somewhere on a table.

But: I again did an experiment on a single hammer felt, treating it EXTREMELY softly, again without any obvious or visible removal of felt or even dust of it. Yet, when I plugged the action back in I again had a horrible clanking sound, as if the whole thing falls apart. It disappeared when I pushed the strings back onto the bridge, but was back shortly after. Again, putting the instrument back together and playing a little, the clanking was gone and the whole sound is now actually much more open and transparent.

I'd appreciate any feedback on this. I was aware that this is a sensitive area, yet watching people filing hammers in a much more brute manner and checking things with a single note first, I considered myself sufficiently safe.

Cheers

piano rookie

I suspect that this is a problem with taking out and replacing the action, not with the hammers.

I'm no voicing expert, but ...

Question: Are ALL of your screwdrivers present and accounted for?

I second BDB and OneWatt. I think there is probably something left in the action.

This is a bit worrying:

The piano should sound better, not worse, after tuning! Can you define what you meant by 'worse'? Very slight discoloured marks at the strike points of hammers should not materially affect the tone.

That was also one thought. But that is definitely not the case and the sound came from the strings and seemingly from the bridge area. I also thought it might be the pin that guides the top cover into the casing, opposite of the hinges, but I doubt it very much. The weird thing is that the rattle was not there at all before and after the tuning, even when the action was pulled out and put back in. But I could reproduce its appearance by treating ONE SPECIFIC hammer felt a second time. In that second try, only THIS ONE note was rattling, none of the others. Before, a number of notes showed the cranking sound.



Indeed, it should improve. Subjectively, it didn't. Maybe I was just too used to the tuning it had upon delivery. The pitch was too low in the treble and too high in the bass. And it needed overall downtuning by about 1,5 Hz. Also, the individual notes sound more metallic and "noisy" now, while they are tuned to proper pitch and all unisons are perfect. That was the reason why I did the whole thing in the first place, the conjecture being that strings with less tension might exhibit inharmonic contributions a bit stronger.

Thanks for sharing your experience that quickly! It sounds like the whole phenomenon seems to be a bit of a mystery. Yet, I do not really wish to experiment any further of course, taking into account my nerves. ;-)
I'll have the technician check the voicing next time, maybe that will shed some light on it.

Cheers

piano rookie

"Clanking" (that may or may not come and go) is what I encounter when I forget I've left some tool (or flashlight, pencil, etc...) dangling on the strings or somewhere else nearby, often while tuning. It's terribly jarring and blows my mind with concern... until I realize how silly I was to have lost track of the item upon its retrieval.

Besides making a scary sound, it you left something inside, there's some danger that whatever it is could wander into a spot where it could break a hammer shank, damage a wippen, whatever. I would check carefully for any missing gear if you've still got any "clanking" or strange noises whatsoever.

Yes, there's nothing inherent in hammers or strings or bridges that can produce "clanking", unless that word is being used here in a sense other than we understand it.
A recording might be helpful. I think it would probably be best to pay the technician to come back out and check for you. Or a different technician.
You mention that the piano seems to have been tuned to 441.5. How did you measure that, and the pitch being low in treble and high in bass?
This all sounds really odd!

What is the brand and and model (if available) of this piano?
About how old is it?

I have a theory, but must wait for the above.

Pwg

Sometimes, on grands- if the piano is not reassembled, you can experience all sorts of frightening things in play-- since the action on many is held in its proper alignment by the cheek-blocks... Perhaps, when you were first shoving the action back into place, you were probably not getting it in the right spot (easy to do this if not careful). This could be why it does just fine AFTER "putting the instrument back together": it would be aligning itself properly when you put the cheek blocks back in (pulling the action into its proper position when you tightened them down).


Just a thought.

Could you post a link to a recording for us to listen to the unwanted sounds?

You didn't use a nail file that shed grains of sand and that these are embedded in the felt?

Ian

Didn't catch this earlier. You are asking us what the "problem" is when you didn't have the piano properly reassembled? If the action isn't in alignment, there can be a variety of issues -- contact with sostenuto and dampers, keyframe slapping on the keybed and some mis-alignment or contact of pedal trapwork coming up through the keybed. If the noise goes away when the action is properly installed, then it most likely isn't a problem at all.

I do agree, however, that with the normal understanding of the descriptive terms used, it sounds like a foreign object in the works somewhere.

What does this mean?

I think we are really at the limit now of what we can diagnose or suggest, without further information, video/sound clips etc.

Yes, sorry for not answering earlier. I was quite busy the last few days.

Thank you a lot for all the suggestions! I'll try to respond globally, please forgive me if I cannot address all your helpful comments.

i) I understand "clanking" as in "rattling" and I totally agree that it sounds like an object left behind in the instrument. But it definitely was not.

ii) Indeed, the first time I put everything back together I also thought it may have been due to the cheek blocks. That's why I paid particular attention to this in the second "experiment". And I was really astonished that VERY little treatment of the hammer felt caused a rattling again, also when the action was put in properly and I checked the action for any rattling. Also, when I put the cheek blocks back it the rattling/clanking was NOT gone immediately.
And I checked first what happens when I just pull the action out and put it back in. In that case all was fine. Only then I did some tiny treatment of the hammer felt.

iii) I cannot record the noise since again it was only there for a short while. After a few minutes of playing it was gone. That is even more puzzling than the appearance.

iv) sand in nail file: No, there was no "debris" whatsoever. Rather, the felt was cleaner than before (which could also alter the property of the strike point?)

v) Pushing the strings to the bridge: I thought maybe some strings were not seated properly on the bridge. Thus I made sure they are by setting them to the bridge. After that the noise was nearly gone, but quickly reappeared. I did this on the same note mentioned in vi), see below.

vi) I did some more investigations: For the single note I looked at in the second try I noticed that not all strings where hit simultaneously. I checked the evenness of the strings and needed to lift the right one (F# in the middle C
octave). I only succeeded a couple of hours ago since I had to find a suitable tool which does actually move the string up and does not break it. (Turns out to be a simple small can opener). Now the note is much better than before.

Having said that, my suspicion is that it was that very set of misaligned strings that might have reacted to very small changes of the hammer felt. I am still puzzled since it was not the only note that rattled for a short while and then settled.

As for the brand: Which piano brand would possibly show such a behaviour? This one is a not so common korean instrument, a hand-made (afaik) Royale Classic 176cm from 1995 in good condition and well maintained, with Renner action and mostly German parts. I am very satisfied with the overall sound and feel, given that it is a budget grand piano.

Thanks again for all your input! In case I take the risk of treating the hammer felts again I'll let you know how I go.

Cheers

piano rookie

maybe it's result old string?
try use cloth which need few alcohol. to rubbing a cloth your problem string

Be sure all the flange screws are tight, especially on the affected notes, from my experience. Naturally, mine were loose because I had removed the part for service and didn't know just how tight to make them without stripping the threads. Definitely made a clicking sound though until it was addressed. Click is not the same as clank, I realize.

Rookie,

It sounds to me like you disturbed the "uniform" striking of the strings by the hammer(s). Hitting one or two strings before the third is struck (or similar) can produce sounds similar to what you described. That was my first thought from your original post.

However, what you really need to do is to stop messing with this yourself since you clearly don't really know what you're doing. Please do not take offense at this statement. I'm not trying to be smart. I'm trying to stop you from doing something that could REALLY COMPLICATE CORRECTION by a competent technician. And, that is what you need. It is virtually impossible for us to give proper guidance when we cannot hear or see what is going on. You need to get someone in there who knows what they are doing, and I will warn you that it's probably going to cost you some money. But I urge you to do it.

You can do a lot of permanent damage when messing around with hammers that already have grooves in them. DON'T DO IT ANYMORE!

Thanks,

Pwg

Understood! See also below. Yet, I have a tech that guides me and that I consult before I do anything. Maybe that softens your concern a little. As for the noise, I found a very likely candidate: The lock in the cross-bar, or rather the extension of the top lock through to the cover. I hope I am describing this correctly. I listened and "ticked" on the inner metal and I could reproduce pretty much the same noise. That also explains why it was not there before and why it disappeared. In any case, the hammer felts are fine, but I certainly won't touch them again anyhow.

But you are absolutely right: I was actually shocked and thought that I HAD done major damage, which fortunately was not the case. But it tought me the lesson. I very much appreciate the knowledge that piano technicians build up in order to properly maintain these extremely complex instruments, and I don't claim to be able to do this myself. But I am also not shy to check things out, collect information, ask someone for support, and help myself as much as I can. I always keep up the tuning in between two tech visits myself here and there, and sometimes I also do some minor adjustments. No more more less, I am far from being capable of maintaining an instrument. But treating the hammer felts was a mistake, I went too far. Even though I worked with zero pressure and did not change shapes, grooves or anything. I am happy that I was lucky!!

Thanks again for all your support, and again for the hint to keep away from critical areas of my instrument. As I wrote, I certainly won't touch the hammer felts ever again. Instead, I will inspect things and point them out to my tech. That is the wiser way of doing it, I suppose.

Cheers

piano rookie

Good news - now you should relax and enjoy making music.

Sounds like your piano is fine, but your furniture is rattling

Those pesky locks. We've all been fooled by them at least once. Good you found it!

Pwg