Stop the over ringing and zinging of my piano

Quick Answer: Unfortunately this will take time to resolve... read the long answer for more info

Quirk Answer: Stop playing the piano.

Long Answer: When you stop playing your piano or play staccato does your piano ring for longer than a second? Or are there loud overtones leaking through for a second or longer after you stop playing the piano? You might have a problem.

Having just recently completed a repair on an older instrument to resolve this, I thought it would be interesting to share with you the potential causes and cures for this issue.

The names of the pedals from left to right are, una corda, sostenuto, sustain. Our concern today it the sustain pedal. This customer's recently acquired instrument had a significant amount of after ring or resonance. Additionally the damper pedal when pressed exhibited an unusual amount of sound.

We must diagnose the problem!

First: Does the pedal have enough lost motion (extra space where the pedal is pressed but the dampers do not move)? Too little or no lost motion leads to after ring, over ring, or leaking dampers. The proper amount is up to the player and technician, but I always suggest a minimal amount of lost motion. In this instance yes, there was enough, in fact too much.

Second: When the pedal is allowed to return to rest position (up) is there a loud hard noise? In this instance yes. This indicates some of the padding to prevent this type of noise is failing, or an obstruction of the damper lever preventing full motion. In this instance, compression of the padding allowing too much movement and contact with a hard surface.

Third: Is there enough lost motion between the back of the key and the damper movement or under lever? Press your key down slowly and watch the damper rise. Does it rise immediately? Or is there a delay? You must have a slight delay, how much of a delay can alter the "feel" of the piano. Too little delay and you again will have after ring, over ring, or leaking dampers. In this instance enough delay between the key and damper mechanism.

We have quickly determined (5-10 minutes) that the extra ring is not due to an improperly adjusted pedal or key... what could be the problem?

Trimmed Tri-Chord Felt

If you look at these dampers you will see what we call "tri-chord" felt having been trimmed until it is almost flat.  Depending on how you look at the felt it should have a "W" shape.  Notice the far right damper felt, the legs or fingers of the felt have been completely trimmed flat.  Now look at the profile picture and see how uneven the felt is.

Trimmed Tri-Chord Felt Profile

This in addition to the hardness of the old damper felt was causing a "zing" on releasing the key.  Customer was frustrated and not happy with the sound of this otherwise beautiful instrument.  The solution?



Replace all of the felt on the damper moulding with new felt, and re bush the pedal rods and adding additional material below the back of the pedal and to the pad on the damper lever.  Confused yet?












How to proceed:

Damper underlever & Set screws

1. If you're satisfied with the damper lift from the key, locate the end damper from each section and loosen the set screw 1/4 - 1/2 turn.  Remember you're only going to loosen the ends of each section, you should have no more than 8 dampers.  Keep them in order!

2. With a sharp razor blade cut off the felt being careful not to remove any wood.  It is better to leave a bit of the glue residue than to cut into the wood.  You can use your razor blade like a scraper to remove the rest of the residue. (alternately if the glue is a clear brown or amber color(hide glue): I have in the past used a 80/20 solution of water/jasco wall paper remover to dissolve the glue holding the damper in place)

Felt Removed

Damper with original felt

Glued and ready

Glued and ready to install

Samples set, remaining section removed

3. With a non-runny glue (I like Weldbond PVA it is a multipurpose glue similar to the industry PVC-E glue) the glue should not slide around once you have applied a small amount.  I then take the replacement felt and use it to make the bead of glue a thin layer on both the damper head and replacement felt.  Hide glue will also work for this but I find it not always the best choice as it is more temperamental in colder weather and doesn't set fast in heat. You will want a glue that setup up quickly enough that the felt doesn't absorb the glue to deeply.  Once you have glued your samples and reset them in their proper place I block the damper tray up to the correct position.  The damper tray is the long rail the moves when you press the pedal causing the damper under levers to rise and fall.  If you block this at the proper height you will find no need to determine when the damper should rise from the key. Since you only took out samples and were happy with the damper lift from the key you will reset the samples to the level of the still installed dampers

One thing I like to do when replacing dampers is to lubricate the damper guide rail bushings as seen below.

Lubricating the guide rail bushing

Why?  I find that this step will flush out any dust or debris from the bushing giving a smooth, quiet sound when the pedal is used.  It is not necessary, but while you have easy access, now is a good time to do it.  Do not use household lubricants! I use only Protek Prolube in all lubricant applications in the piano and @ about $70 per quart it's expensive, but a few drops to saturate the bushing is adequate for quite a long time.

After replacing all your dampers you will likely need to align the damper head to be straight. I cinch the damper set screw slightly then with a pair of needle nose pliers, carefully twist the damper wire until the head is parallel with the strings then tighten the screw just a bit more.  When you have replaced all of the damper felts test the pedal.  What you need to look for are dampers that rise too early or too late. Re-adjust as necessary. Your dampers should move at the same time.  One test I like to use is after installation to block the dampers until you just get about a half of a second ring when the string is plucked or played. Every note should have the same duration of ring as your test note. For those that don't ring long enough the damper is rising too late, for those that ring too long, the damper is rising too soon.  If your dampers visually rise properly this "fine" adjust may not be necessary if you use the pedal in only the down or up position.  If however your sustain pedal technique has many "steps" this step will likely be necessary.

Now re-assemble the piano and test again using our three tests from the beginning: Pedal Lost motion, Pedal noise, and Damper lift from the key. Make sure all are in proper alignment. especially ensure you have sufficient space between the back of the key and the damper lift.  I always am a bit more generous with new damper replacement due to the fact that these new felts will compress a bit and reduce the amount of room you have provided between the back of the key and the damper under lever, if you account for this compression you will save yourself a second visit to adjust for ringing dampers.

This process will take an experienced efficient technician between 4 and 6 hours if no other adjustments are necessary.  If the damper wires need to be adjusted for proper alignment this could take significantly more time.  When requesting this type of work ensure that your technician inspects the damper wire alignment and quotes his bid accordingly.  I find however that adjusting damper wire to be unnecessary unless a technician in the past adjusted them improperly, the factory generally does a good job when installing this part.

Note: For a short period Kawai grand pianos had an issue where in the bass section one string would ring while the other was silenced by the damper.  If you have this issue contact your nearest Kawai dealer and ask them to send a technician to adjust the damper rail placement.  The rail may only need to be shifted a very slight amount to resolve the issue and is best done by a qualified technician. This service may likely be covered under warranty if your piano is within the warranty period.  Ask the servicing technician to call the manufacturer's technical support directly for instructions on resolving this simple yet quite annoying issue.  Kawai has since corrected the issue and I have not seen it for a few years.

Technicians, send me a message with your email and I will describe the repair as it was presented to me by Kawai.