Damper Lift

Either you're good at adjusting dampers, or you're not.  The difficulty lies in the adjusting mechanism, which is, simply, a wire.  You bend it a little this way, a little that way, a little more over here, give it a twist, and the damper sits right.  Or it doesn't.  It's a puzzle in three dimensions, and you need to have good ear-eye-hand coordination along with the ability to imagine, in your mind's eye and ear, what will happen when you bend the wire.  I am good at adjusting dampers, I even enjoy it, and as a result I've been called in on occasion to help other technicians who are having difficulty.

Picture a grand piano.  The wooden damper head has felt (usually two pieces) glued to it, and the head sits on top of the string, felt side down, damping any vibration.  There needs to be a way to lift the damper head off the string, so a stiff wire is attached to the side of the head, and it drops down through a guide hole and inserts into a wooden piece called the damper lever.  When you press the key, or the damper pedal, it is this lever which is lifted, thus lifting the damper head.

The wire is held in place in the lever with a little screw that clamps down on it.  The distance from the damper head to the damper lever can be adjusted by sliding the lever up or down on the wire, and then tightening the screw.  This is called regulating the damper height, and it is the most common adjustment made, an easy adjustment that most technicians master.

Because there are two ways to lift the damper, using either the key or the pedal, the damper height has to be adjusted so the damper lifts correctly either way.  Sometimes getting this right involves making adjustments to the key or the pedal mechanism, but usually one adjusts the damper height so that each key lifts its damper at the same place in the keystroke, and all the dampers lift simultaneously with the pedal.  If a damper lifts too soon, it is said to be fast, or early - the damper may not quite fully sit on the string and damp the vibration.  If a damper is slow, or late, it may not lift enough to allow the string to vibrate.

When the back of the key picks up the damper lever, your finger can feel the weight of the damper.  If the dampers lift unevenly, you can feel this in the keys.  You can also hear it when you press down and let up on the damper pedal - on the way down, some notes will ring out before others, and on the way up some notes will damp sooner than others.  This was the complaint of one of my clients recently - he had noticed that the bass dampers were lifting before the treble dampers.  He has exquisite pedal technique, and this unevenness was driving him crazy.

The most common problem, aside from unevenness, is having the dampers in the middle lift sooner than the dampers at either end.  This usually indicates warping of the board that lifts all the dampers when you depress the pedal.  This board, called the damper lift tray, is lifted somewhere near the middle by a dowel pushed up by the pedal.  The ends of the tray, thus unsupported, can sag under the weight of all the dampers.  Over time, the sag can become permanent, and the damper heights (or the tray itself) will need to be adjusted.

It's also not unusual to have the bass or tenor dampers lift early because of how their felts settle and compress over time.  The dampers sit lower and lower, causing them to be lifted earlier and earlier.  The problem with my client's Steinway grand was a little different, though.  The treble dampers lifted pretty evenly, and the bass dampers did also, but the whole bass section lifted earlier than the treble section.

I have come across this problem before in older Steinways.  You set the damper height so that the dampers are lifted correctly by the keys, and then when you use the pedal the whole bass damper section lifts early.  It turns out that the thickness of the damper-lifting shelf at the back of the key is slightly greater in the bass section.  I don't know if this was deliberate on Steinway's part, a notion about damper lift they might have had for a while, or just a manufacturing irregularity.

One solution is to shim the tray - slip a strip of card under the tray felt in the treble section.  I took a gamble and decided to even out the damper lift in the usual way, by adjusting the damper height so that the pedal would lift the dampers simultaneously.  In particular, I dropped the height of the treble dampers so they would lift earlier (because the owner was also complaining about insufficient pedal throw).  This would mean, though, that the dampers in the treble would lift slightly sooner in the keystroke than would the dampers in the bass.  The gamble was that the difference would be unnoticeable to the player, and it worked.  Another happy customer!

A note about the diagram:  this is the arrangement in most makes of grands, but not Steinway.  The lift tray is different in a Steinway.  First, the levers are attached to the tray rather than to their own rail, which makes for some interesting geometry issues.  Second, Steinways do not have the little brass adjuster on the tray, underneath each lever, that you can see in the diagram.  That adjuster is wonderful - you can be really sloppy regulating the damper lift, and then just use the adjusters to even out your sloppiness.  The Steinway arrangement forces you to be much more careful, and irregularities in the tray (which should be minimal) can be worked out later by shimming.