Pianotech

Check the down bearing in that area. My initial observations suggest that a little-to-no down bearing load allows the soundboard to rise and fall rapidly. This is only my preliminary observation, not a theory or fact.

Downbearing on a healthy belley in the melody octave should be 1-1.5 mm.  Is tuning pin torque even? Check plate screws, lag bolts and pinblock/plate flange

for gaps with a feeler guage.  Absolutely consider capo surface and profile.

Check the down bearing in that area. My initial observations suggest that a little-to-no down bearing load allows the soundboard to rise and fall rapidly. This is only my preliminary observation, not a theory or fact.

Parker,

How do you measure downbearing in linear mode? I've always measured in degrees.

Roger 

Downbearing on a healthy belley in the melody octave should be 1-1.5 mm.  Is tuning pin torque even? Check plate screws, lag bolts and pinblock/plate flange

for gaps with a feeler guage.  Absolutely consider capo surface and profile.

Check the down bearing in that area. My initial observations suggest that a little-to-no down bearing load allows the soundboard to rise and fall rapidly. This is only my preliminary observation, not a theory or fact.

I have a General temp/humidity guage that does datalogging.

My first suspicion would actually be way too much (or significantly uneven) downbearing, though would agree about the V-bar as a factor as well. 

I would take a close look at the crown to see if it is evenly, or unevenly distributed across the board. If, under the bridge it seems to start resembling "oil-canning", excess DB is indicated. This tends to cause the board to convulse weirdly with the slightest of humidity change. If combined with rock hard hammers and a somewhat erratic short sustain issue, then that's strong circumstantial evidence in that direction. 

Peter Grey Piano Doctor 

I have a General temp/humidity guage that does datalogging.

I thought seriously about the V bar issue but the problem is widespread in the agraffe sections too. Tuning pin torque is not an issue. I believe I checked plate bolts at some point but it's worth checking again. I am a bit skeptical about humidity or temperature being the problem because I've tuned a lot of pianos in unstable climates but never had one act like this!  However, humidity changes in tandem with excess downbearing (or too little) is an intriguing idea.

Peter, would rock hard hammers be a symptom because someone had to add excess lacquer to get decent volume?

As to gaps between pin block and flange, my experience has been one of finding gaps in pianos that didn't really have instability problems. I guess it's worth checking. Does anyone have experience with this problem and what it's exact symptoms are? 

Stay tuned, it may be a few weeks before I can get back to that piano.

My first suspicion would actually be way too much (or significantly uneven) downbearing, though would agree about the V-bar as a factor as well. 

I would take a close look at the crown to see if it is evenly, or unevenly distributed across the board. If, under the bridge it seems to start resembling "oil-canning", excess DB is indicated. This tends to cause the board to convulse weirdly with the slightest of humidity change. If combined with rock hard hammers and a somewhat erratic short sustain issue, then that's strong circumstantial evidence in that direction. 

Peter Grey Piano Doctor 

I have a General temp/humidity guage that does datalogging.

I thought seriously about the V bar issue but the problem is widespread in the agraffe sections too. Tuning pin torque is not an issue. I believe I checked plate bolts at some point but it's worth checking again. I am a bit skeptical about humidity or temperature being the problem because I've tuned a lot of pianos in unstable climates but never had one act like this!  However, humidity changes in tandem with excess downbearing (or too little) is an intriguing idea.

Peter, would rock hard hammers be a symptom because someone had to add excess lacquer to get decent volume?

As to gaps between pin block and flange, my experience has been one of finding gaps in pianos that didn't really have instability problems. I guess it's worth checking. Does anyone have experience with this problem and what it's exact symptoms are? 

Stay tuned, it may be a few weeks before I can get back to that piano.

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John Pope
University of Kentucky School of Music
Lexington, KY
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Original Message:
Sent: 02-28-2026 20:45
From: Peter Grey
Subject: Tuning Instability on 80s Steinway D

My first suspicion would actually be way too much (or significantly uneven) downbearing, though would agree about the V-bar as a factor as well. 

I would take a close look at the crown to see if it is evenly, or unevenly distributed across the board. If, under the bridge it seems to start resembling "oil-canning", excess DB is indicated. This tends to cause the board to convulse weirdly with the slightest of humidity change. If combined with rock hard hammers and a somewhat erratic short sustain issue, then that's strong circumstantial evidence in that direction. 

Peter Grey Piano Doctor 

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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com


Original Message:
Sent: 02-28-2026 12:12
From: Parker Leigh
Subject: Tuning Instability on 80s Steinway D

I have a General temp/humidity guage that does datalogging.

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Parker Leigh RPT
Winchester VA
(540) 722-3865