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nutsbolts.jpg (6326 bytes)     Tech Talk

with Kendall Ross Bean

Tech Talk is the section of this web site devoted to discussions of  items of concern to piano technicians and those interested in piano technology.  We will continue to feature  new topics.   Ideas for new discussion are welcomed. Tell us what you would like to talk about. Send suggestions to contact us.

Contents of Tech Talk Forum:

      Piano Noise Troubleshooting

      "Gray Market" Pianos

      Seasoning Pianos for Different Climates.

For table of contents and internal navigation links for this article click HERE.

This installment of tech talk is about

Piano Noise Troubleshooting

Nothing drives pianists crazy faster than an elusive, annoying rattle, squeak, or buzz. A piano technician may have done a superb job rebuilding, regulating and/or voicing an instrument, but if that pedal still squeaks every time it's depressed, or if that string still buzzes, that's what the customer will remember- every time they sit down at the piano. One of the skilled piano technician's greatest assets is the ability to track down, and fix, piano noises, in a minimum of time.

A piano is a very large entity, and the task of locating those obstinate noises inside that wilderness of wood and wire, and among those thousands of parts, can often be daunting, if not simply overwhelming. It's wise to have some tricks in one's bag, called isolation techniques, to speedily locate the cause of the problem. Aside from that, there is no substitute for experience: knowing what noises are usually caused by what parts.

One of the first steps, of course, is to try and localize the source of the noise. Does it seem to be coming from down by the pedals, or from  inside the action, or from a cabinet part, the soundboard, a string? This is where it is often helpful to have an assistant.  It can be difficult to go where the noise is and play the offending note at the same time, or to reach the keyboard while you're searching for things in the tail of a grand. If the noise is only heard when a single note, or a few particular notes are played, have the assistant play that note or notes repeatedly, at the volume level that produces the noise, while you listen to various places around the piano. As you get closer to the source of the noise (hopefully) it will get louder. At the point where the noise is the loudest you may actually be able to see something: perhaps a piece of candy or a paper clip on the soundboard, or maybe a pedal lever or rod rubbing against something. Try to discover under what conditions the noise occurs: Does it happen  when the pedal is depressed? Not depressed?  When certain notes are played together, or one after the other? When the piano's lid is up? Down? When you hold the damper up on the note that is causing the noise, or only when the damper comes down? What kind of a noise is it? Metallic? Woody? High pitched? Low pitched? What kind of materials might be causing the noise? Are they rubbing, hitting, rattling? Do your Sherlock Holmes homework, first, and you may not have to spend as much time hunting.


One common noise is the buzz. This can be anything from a low frequency rattle to a high pitched zing or hiss. Since there are so many different things that can cause buzzes, they can be some of the most elusive problems to find. Here are some of the more frequent causes.


One type of buzz occurs  when damper felt (usually in the low bass) has become old and hardened with age, or when glue has been spilled on the string contact surface of a damper felt, perhaps during installation at the factory. If hard or contaminated damper felt is the problem, careful listening will reveal that the buzz does not occur initially when the key is depressed, (when the hammer strikes the string) but afterwards, as the key is released (as the damper returns to the string). To verify this, play the note again, but hold the key down and gradually release it. If the buzz appears only as the damper comes back into contact with the string, you know what you have. The fix is usually to locate and remove the spot of glue or other contamination, or simply replace the old, hard felts, if a number of dampers are affected. Sometimes a short term solution is to fluff the damper felt up with the sandpaper file.
Incidentally, stray glue drips account for a large number of noises found in pianos. More on this later.

Damper wires

Damper wires in a grand pass up through the strings and sometimes the clearance between the string and damper wire is not sufficient. To test for this condition, check visually to see if the damper wire seems too close to the string; if so, hold the damper wire away from the string as you play the note, and see if the buzz goes away. Under the capo bar, a misaligned string can generally be slid over and away from the damper wire, but in the agraffe section,  there is no way to move the string right or left, so the guide rail holes may need to be plugged and redrilled. A quick fix often may be achieved by bending the damper wire slightly (underneath the guide rail), so that it bears against the far side of the guide hole, away from the string. If this doesn't work,  you can try shimming the wire away from the string by either inserting a small piece of felt in the side of the guide hole closest to the string, or by reaming either the wood or the felt on the side away from the string, or ultimately, plugging, redrilling and rebushing a misdrilled hole. In severe cases of misalignment, where numerous damper wires are too close to the string, the entire damper guide rail may need to be repositioned.

Foreign objects on Soundboard

Many buzzes are caused by small, hard foreign objects falling on the soundboard: a tack, a paper clip, a loose screw, or any number of other things.  This happens mostly on grands,  since the grand soundboard is horizontal and provides a convenient net or magnet for anything that happens to fall in there. On verticals, where the soundboard is oriented differently, this doesn't occur as often, but objects can still get lodged on the sides of bridges, or on other "shelves." Sometimes a grand's bridges have gaps underneath, where small brass continuous hinge screws can fall and lodge unnoticed. At other times there may be a foreign object on the soundboard underneath the plate. In these cases, where the object is more or less invisible and/or inaccessible, your best bet is to try and fish around under the bridge or the plate with a soundboard steel, or other, similar tool. The trick is to dislodge whatever might be there and roll or scoot out across the soundboard where you can see and remove it. The offending object doesn't have to be large. Sometimes very loud buzzes and rattles are caused by extremely small objects. An object on the soundboard will usually buzz with a few or several different notes, whereas a string buzz (below) is usually confined to one note, or one string. In addition, with an object on the soundboard you can often thump  the soundboard with your fist and induce the buzz without playing any notes. Many pianos have soundboard buttons and screws for holding the bridges to the soundboard, not only under the bass bridge, but often also for the treble bridge as well. (Most high quality pianos use dowels to attach the bridges to the ribs, as screws and buttons can tend to come loose and rattle over time.) Try checking the soundboard buttons to see if they are loose or rattling, or whether the screws need tightening.

String buzzes

If you have isolated the buzz to a specific note, and the noise seems to be coming from the soundboard/bridge/plate area, but you've checked and there doesn't seem to be anything on the soundboard, next, see if you can isolate the buzz to an individual string. One at a time, using your finger or a rubber wedge, mute off each string in turn for that note to see if the noise stops. (On the lowest bass notes where there is only one string per note, skip this step.) If you have now isolated the buzz to one particular string, there are a couple of options you have.

Loose windings

First, if it is a wound string (bass string) the usual reason for a buzz is that the copper or iron wrapping around the string is loose. Let down the tension on that string, unhook the loop from the hitch pin, and twist it, giving it a full turn in the direction that will tighten the winding (turn the string in the direction that the end of the winding is pointing). Keeping it twisted, replace the loop on the hitch pin and pull the string back up to pitch. If, after doing this, the string still buzzes, you may have to replace it, although you can try giving it another twist. (But never more than 2, or the string will sound funny. The lowest bass strings usually can't be twisted more than one full turn.) If the string already has been twisted (if it tends to want to untwist when you take the loop off the hitch pin) another technician has probably already tried to fix the strings this way. But sometimes the factory gives new bass strings a twist when the piano is strung, so you can still try adding another twist. Try to see how many turns the string wants to untwist when you take it off the hitch pin: half a turn, a full turn, one and a half turns? Like I said, you can twist a string up to two turns if it isn't one of the lowest bass strings.

Capo bar problems

If the string is in the treble under the capo d'astro bar the first thing to do to pin down the source of the string buzz is to try sliding the string over to a different place under the capo bar. This will likely detune the string, but if the buzz vanishes, there is a probably a groove in, or a problem with, the capo bar. You can actually slide several buzzy strings over slightly in this way to find a better place for them on a worn or grooved capo bar. Ultimately, though, if the capo bar has numerous  or severe grooves or imperfections, requiring the repositioning of many strings,  the capo bar should be reshaped or repaired. Piano wire is extremely hard, compared to the cast iron of the capo bar, and will actually cut fairly deep grooves in it with repeated playing and tunings over time. When a piano is restrung by a competent rebuilder,  the capo bar is usually filed or reshaped to remove the grooves and restore it to it's proper profile, just as hammers are reshaped when they get too grooved.

Agraffe buzzes

Agraffes are generally not as frequent a source of buzzes as capo bars are.  On most grands, you may note a number of zings and hisses in the capo bar sections but as soon as you cross over to the agraffe sections everything usually quiets down. Brass is a softer metal than the cast iron of the capo bar, and seems to be more forgiving of grooves and other imperfections. You can however, get buzzes in the agraffe section, as well.  It's generally not the agraffe that's at fault, but how the string passes through it. Agraffe buzzes are usually caused by lack of bearing against the top of the agraffe hole.  To test for this condition, put a screwdriver tip under a buzzing string on the tuning pin side of the agraffe, and, while lifting the string up against the top of the agraffe hole, play the note.  If the buzz then disappears, it may be necessary to put some additional felt under the string between the tuning pin and the agraffe to give it some more upward bearing.  Sometimes technicians get over-exuberant in stretching or lifting new strings, and inadvertently put a kink in the wire inside the agraffe.  This effectively creates the same situation as the above: the string is simply just not getting enough bearing against the agraffe, because of the kink.  To test for this condition, if the string is the conventional type shared by two tuning pins, you can let out some wire from one tuning pin and take some up on the other so that the kink is moved out of the agraffe into the non-speaking segment of the string between the tuning pin and the agraffe.  If there is only one kink in the string, this will usually fix the problem and you can just leave the string there.  Unfortunately, what often happens is the string will have two kinks in it and while you move one out of the speaking segment, you move the other IN.  You might, now that you can see it, try and smooth the kink out, but ultimately you may have to replace the string.   It never hurts to try.   Having to go through this a few times should cure most any technician of the bad habit of over-lifting or over-stretching strings.

Bridge pins and notches

Other causes of a buzzy string are loose bridge pins, and poorly made or damaged bridge notches.   First, if sliding the string to a different place under the capo bar doesn't eliminate the buzz, and if the bridge notch appears to be in good shape, try tapping the string down to the bridge at the pin,or driving the bridgepin down into the bridge a little further, using a brass or maple rod and a small hammer.  You can also try rotating the bridgepin 180 degrees,  in case it's grooved or nicked where the string passes around it.  Also check to see that the bridge notch runs right down the center of the bridge pin holes.  If the notch is forward of the pins/holes, that's easy to fix: just unhook  the strings for that note from their hitch pins, move them aside, remove the bridge pins and get your chisel out. (When removing the bridgepins, make sure your pliers don't grip anywhere the string contacts the pins if you're planning on reusing them, otherwise, install new pins.  If the notch is behind the bridge pins, you will have to fill the existing pin holes, and drill new ones further back, on the notch line.

Most of the above are what are called termination problems, where the string isn't quite sure where it begins or ends, and thus has a hard time vibrating correctly. Many times this results in false beats, but just as often it's a buzz. Sometimes with severe termination problems there simply is no quick fix short of rebuilding the piano, especially if the bridges, soundboard or capo bar are in poor condition.

Hammer problems

Sometimes buzzes are caused by a hard spot where something has spilled on the hammer felt, or where the hammer felt has been excessively chemically hardened, or else has become packed from years of playing. If the piano has an una corda pedal you can try shifting the hammer over slightly so that the ungrooved portion strikes the string, or, on pianos where the keyframe doesn't shift, loosen the hammer flange screw and space the hammer over a bit. If doing this makes the buzz disappear, then the hammer is the problem. Try fluffing up (scratching) the hammer groove corresponding to the problem string with a voicing needle and see if that eliminates the buzz. Also, when hammers have been hardened,  a hard edge is often formed. If this is not softened or rounded off with a sandpaper file, it will buzz when the hammers are shifted under the strings by the soft (or una corda) pedal.

In new pianos, or recently restrung ones where the capo bar has been reshaped, the duplex (non-damped segments of the string) will often hiss and zing, and even buzz. To check to see if this is the case, try damping the duplex strings with you fingers while you play the note, and see if it makes a significant difference. If the duplex is the problem, you may have to mute off some duplex strings, or detune them if feasible.

Here's a buzz troubleshooting checklist:

  • Loose keylock rail nuts, or screws

  • Loose hammer rail nuts (sometimes they will produce a knocking or clicking sound rather than a buzz)

  • Loose sostenuto rail or knife, or attachments, or felt bushings on knife have fallen out.

  • Gap between keyframe pin and strike point adjuster in cheek block (grands) -(also may produce clicks or knocks.)

  • Damper wires too close to strings (grands)

  • Loose lead weights in damper underlevers. Loose damper wire screws.

  • Backchecks or backcheck wires hitting sostenuto rail or dampers

  • Hingepins and/or hinge wires loose in cabinet hinges  -

  • Crack in the soundboard where the two edges are vibrating against each other

  • Loose soundboard buttons or screws underneath board.

  • Soundboard separation at rib or rim

  • Worn, loose, or grooved bridgepins (this is why turning, or driving a bridgepin in further, will often eliminate a buzz)

Piano Hardware

Hinges, casters, locks and cabinet hardware are often a prime source of buzzes and rattles. Screws come loose, or else the pin, or the long wire, or rod that holds the two halves of the hinge together becomes loose, and buzzes at certain frequencies. Sometimes on long continuous hinges with multiple segments, the screws holding down a segment or segments are loose. This happens frequently after a piano has been refinished and hardware is reinstalled without fixing stripped screw holes. A buzzy lid hinge can often be detected by opening or closing the lid or lid foldover, to see if the sound changes or disappears. Lid prop sticks on grands sometimes have buzzy hinges or half sticks, or their felt pads or rubber buttons are hardened with age or missing. Short metal lid props on uprights often become loose or lose their rubber bumpers.

Music desk supports, slides, hinges and screws should all be checked as well. Hard rubber buttons on the lid prop will often rattle against the plate and/or the lid when the lid is down. One source of a particularly elusive buzz  on a grand was found, finally, after several hours of searching, to be a caster which had lost all its grease, leaving the ball bearings free to rattle around.

On hinges, if the problem is not simply a loose screw, the pin or wire can be removed and made to fit more tightly by putting some kinks or small bends in it ( for long continuous hinges) or (for regular hinges) the pin can be made tighter by peening, a process of putting several dimples in the pin with a hammer and a center punch. Sometimes, though, even these techniques will not silence a noisy hinge, and then the only recourse you have is to replace it, and hope the new one doesn't buzz as well.

Squeaks, and clicks, etc.


Pedals, by virtue of their fairly complex linkages, and also by virtue of the fact that they are used almost constantly, are a common source of groans, creaks, knocks, squeaks and other undesirable accompaniment. If operating the pedal is causing the noise, you can usually isolate the problem to a certain area of the pedal linkage by moving one particular part, while holding the other parts immobile. For example, on a grand, start with the upper trapwork levers, at the top of the pedal rod. Move the lever with one hand while holding the rod stationary with the other. Did the squeak go away? If so, you've eliminated the upper trapwork as a source. Squeak still there? Then you've ruled out the rods and pedals. If neither rods nor levers squeak by themselves but make noise when they're back together, it's probably the connecting or contact point between the two. The rule is simple: Try to move smaller groups of parts, or one part at a time, to see which part, or group of parts, squeaks when moved.

One frequently missed cause of  squeaks and groans in the pedal is those long L-shaped brass or steel pins that the levers pivot on. Turning these pins an eighth to a quarter turn one way or another will often cause the noise to diminish or even go away entirely. If that happens, you know you've found the cause. To fix the noise for good, pull the pin out, clean it off and polish it if necessary, then put some Protek™ or VJ lube™ on it and push it back in place. In a pinch, lip balm (Chapstick™, etc. ) is supposed to work, too. If the felt bushings are in poor condition, or if the pedal pin is badly scored or worn, they will have to be replaced.

Another area oft overlooked on both grands and uprights is the pivots on which the damper tray or damper lift rod swing. Here, access is the main problem. On a vertical you usually have to pull the action at the least, and on some grands, if you can't get back in there with a small artists brush and some lubricant, you may have to pull the damper underlever assembly (no fun.) (Fortunately this is seldom necessary.)

The wood, plastic or brass damper tray lift dowel that passes through the keybed on grands is another common source of squeaks. The felt in the keybed through which this dowel passes often gets dirty, caked with old grease or graphite, or worn through; also, because the dowel pushes on the tray at various angles, it is possible that the edge of the dowel may contact the tray and squeak, even though there is a felt or rubber spacer (punching) there. Turning this dowel a quarter to a half turn one way or the other will often stop or lessen the squeak, and is a good way to tell if it's the problem. The metal pins on the ends of this dowel, if present, may also be in need of a drop of lubricant.


While we're on the subject of pedals, the question always arises, what do you lubricate with? Over the years I have had the opportunity to try many different formulations, with varying degrees of success. One product I always keep on hand is Protek™ CLP, available from piano supply houses. It is a good all round cleaner /lubricant that can be used on just about any material in a piano: wood, metal, felt, and even leather in many cases. The other indispensable lubricant for pedals is a mixture of Vaseline and talc. It is available commercially from piano supply houses,  with the addition of lanolin, under the name VJ Lube™ (in honor of Los Angeles technician Vic Jackson, who, I understand,   developed it). I make my own, without the lanolin, (which I can never seem to find), but it seems to work excellently all the same. Both of these products work well on those L-shaped pedal pivot pins, pedal rod ends, felt guide bushings,  metal to wood, spring to wood and spring to buckskin contact points, etc, and are, after having tried many other things with varying success,  the lubricants I seem to end up using the most often. One caveat: Vaseline tends to rot certain kinds of rubber that are sometimes found in pedal linkages, so use care with the VJ lube around rubber.

Ultimately, when attempting to eliminate noises, there is no substitute for clean surfaces in good condition, so if you have worn, dirty or deteriorating buckskin or felt, rusty or scored pins, loose pedal blocks, stripped screws, felt caked with layers of dirty grease graphite etc., it's best to repair, clean or replace as needed, or no amount of lubricant is going to fix the problem for long. Always clean or replace the leather strips which contact trap springs before lubricating. Make sure all contact surfaces are smooth or polished and in good physical condition, before assuming that they will continue to work noiselessly for longer than a couple of days after your service call.


Keys rubbing against their neighbors will squeak or click, and are usually easy to spot: frequently one or the other key will fail to return to it's up position. Align, sand or shave as needed. Wood splinters and other small objects that fall in between the keys are another source of rubbing sounds, knocks, and squeaks, and can usually be dislodged with a soundboard steel passed between the keys, without having to remove the action. A stray spot of glue on a balance rail punching is often found to be the cause of a very elusive squeak or click. And believe it or not, sometimes balance rail pins will squeak at the balance hole, for no apparent reason. Apply Protek.

Don't forget the obvious: A keyslip too close to the keys, keys that have been recovered with fronts that are too long and which hit the keyframe, keytops or ivories that have come loose or unglued in spots but are still hanging on, fallboards and keylock rails that have no felt, keys leveled too high which hit the back of the fallboard on return, misadjusted keylock rails that allow the keys to hit the fallboard on return, and new keytops that have not been sufficiently trimmed will all make tapping or clicking sounds. Key leads, also, can, and do, come loose.

Key bushings

Key bushings themselves are often a source of  squeaks. Sometimes too much glue will soak into the bushing on installation, other times it's just low quality felt. To find the squeaking keybushing, first hold the sticker or whippen up out of the way, and move the key up and down. If the squeak is still there,  you've eliminated the whippen and everything above it as a source of the noise. Now, continuing to play the key, push first one side, and then the other side of the key bushing against the pin. Do this with the front rail bushing and then with the center rail bushing. You will generally find that the squeak gets louder when you push one side of the keybushing felt against either the front or balance rail pin, and that the noise diminishes when you push on the other side. Remove the key from the action and check for wood splinters, debris, or glue drips in the keybushing or mortise. If there is glue or debris,  remove it. If you don't see anything, give the keybushing a drop or two of Protek or equivalent, or simply fluff up the felt a little with a voicing needle. If the noise returns after a couple of weeks, you may have to replace the keybushing , or at the worst, rebush the keys.

Buckskin, Knuckles

Buckskin often gets overlooked as a possible source of problems, but knuckle buckskin often can, and does, cause a host of unpleasant noises, from squeaks to actual clicks and knocks. To begin with, there are all different qualities of buckskin;  additionally, leather often hardens with age. Many Asian pianos and replacement parts have "squeaky knuckle syndrome" or "noisy knuckle syndrome" due to certain qualities of, or installation procedures used on, the knuckle buckskin. I was once told (by a knowledgeable technician) that a frequent problem was the buckskin being stretched too tightly around the knuckle core felt when the knuckles were originally made. We found that many action clicks and thunks could be significantly reduced or eliminated by  softening the knuckle leather, either by brushing it up with a suede brush, or, in worst case scenarios, going at it gingerly with a voicing needle. Some piano companies, as a warranty measure, will just send you a new set of knuckles and have you replace the old ones. For squeaky knuckles, if brushing, cleaning and talcing them doesn't work, there's always Protek, which always seems to work. By the way, this may seem like an ad for Protek, but it's not. It just happens to work for a lot of different things.

Action clicks and noises

Many sources of action noises, clicks, squeaks, knocks, and the like, are common to both vertical and grand pianos. But some are particular to one or the other. For example, a frequent cause of clicks in a vertical pianos, but not in grands, is bent bridle wires hitting adjacent backcheck wires. Also, in vertical pianos, damper wires and damper heads often have extremely tight clearances,  and if only slightly misaligned, may actually contact each other, creating a click. Look also for things like dislodged jack springs, loose spring rails, screws or nuts, jack flanges that have come unglued from the whippen, loose hammer heads, and loose whippen and hammer flange screws. It is often amazing to note how many noises can be eliminated in a piano simply by tightening all the action screws.


Often, bent or misaligned repetition springs will click against a spoon, or else squeak where they enter the jack or contact the rep lever. A drop of Protek will usually take care of the squeak, and judicious bending of the spring will usually get it away from the spoon. On grands with whippen auxiliary springs, the springs will sometimes become dislodged, unnoticed, from their string loops. Because they're behind the action down by the whippen flanges, they're often overlooked, but they will produce a definite click if not secured in the cord. Also, damper lever springs will sometimes squeak against the damper levers. They are difficult to access, but you can usually get a drop or two of Protek in there on a small artist's brush.

Noises outside the piano

Don't overlook the possibility that the particular noise you are trying to locate may not originate in the piano. Lamps and lamp fixtures, light bulb filaments, heater shrouds and sheet metal, metronomes, clocks, windowframes, glass, venetian blinds, and a host of other things near the piano may resonate sympathetically with the vibrations produced by the instrument. A good directional sense of hearing is indispensible when trying to find these sources of "piano noise".

There are, of course, many more causes of piano noise, too numerous to mention in this article. Hopefully, though, this has given you a few tips and tricks to add to your list, and perhaps some quicker ways to get to the heart of the problem.


Table of Contents:

1.    Introduction
2.     Dampers
3.     Damper wires
4.     Foreign objects on soundboard
5.     String Buzzes
6.     Loose windings
7.     Capo bar problems
8.     Agraffe Buzzes
9.     Bridge pins & notches
10.   Hammer problems
11.   Piano hardware
12.   Pedals
13.   Lubricants
14.   Keys
15.   Key bushings
16.   Buckskin, knuckles
17.   Action clicks & noises
18.   Springs

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