10 years ago by
A Pianist
Well, this is the 5th time I've written a response to this. Trying to keep it simple isn't easy, but here goes again.
Yes, Alan, I think you are right and what is being referred to is what happens right at the point of escapement.
If there is any resistance here, it will be felt.
As the key is pushed further down, it will suddenly give way and continue down to the bottom of the key bed. During that time, the hammer has been sent on its way, and you have no more control over what is happening.
The escape of the jack from the knuckle should be as frictionless as possible. There should not be a feeling of resistance, but rather, a feeling of smoothness as the jack returns under the knuckle, ready to play the note again.
Three things are felt when we push down the key.
1st is the touch of the key top and as the key is pressed, the breaking of inertia to get the key moving. This will be followed almost immediately by the weight of the dampers lifting.
If the piano is regulated correctly and working correctly, the movement of the action will seem effortless, because all things are balanced and leveraged perfectly.
Half way through the key stroke, the jack, which is being pushed up against the knuckle (that is on the hammer shaft), the knuckle being round, the jack moves out away from this "ledge," as it propels the hammer to the string.
As the hammer is moving to strike the string, the jack moves back under the knuckle--before it has time to return to where it was, and the note is ready to be played again as soon as the knuckle touches the tip of the jack.
This is the beauty of a grand piano action. The key does not have to be pressed all the way down for escapement to take place and the jack to be repositioned beneath the knuckle. --which gives the ability to play rapidly and also with power.
If there is too much resistance, perhaps the knuckle has flattened or is too large/heavy. You can feel a "catch" in trying to move the key down. This is because the jack has hung up on the ledge.
If you feel resistance here, that is wrong and will take control away. What you should feel, if anything, is a giving way of any resistance--into the lost motion of the key--and the jack has already kicked out and returned beneath the knuckle.
It will be very smooth. You know exactly where the place is--not because of resistance being there, but because of resistance going away.
The less resistance, the less friction, the less effort to overcome inertia and the easier it is to play the piano as well as have control. The piano will not feel heavy, even though it takes 50 g. to push down the key.
Because all things are balanced properly, inertia is overcome. It is not so much the effort (resistance) to press the key down (down weight & up weight), that makes a piano feel "catchy," or heavy, but there being too much inertia to make the piano play as you want. This is called the "touchweight."
If the inertia is high, you will feel it as heaviness, sluggishness, resistance, and it will make you quite tired. Some types of playing, rapid, reptition, will be or soon become impossible. It just takes too much effort to overcome the force necessary to move the mass of the action.
The third "resistance" will be when the key is pressed passed the ledge and bottoms on the key bed. How much of this 'aftertouch' there is is often a matter of choice. But It is especially useful in forte passages and at speed.
Using the weight of the arm and shoulder, the key goes all the way to the keybed. The bottom of the keybed being solid, reflects the force back into the hand and gives a spring to the movement. This sets you up to be able to do again, the same thing.
So the short answer is the escapement is when the jack stops pushing up on the knuckle, which is attached to the hammer shank, and the cycle is completed by the jack returning beneath the knuckle, before it has a chance to slip past the repositioning, jack.
If there is resistance at the ledge, it's because the jack is hung up. It won't be able to get to its return position beneath the knuckle, and the next time you play it (if you haven't gone all the way to the keybed), there will be only a "thump."
I know. All this is clear as mud.
The grand action is really a marvel.
When it's set right, the movement and perceived weight of having to push down the keys, does not get in the way of what you (we) are trying to do.
Playing is effortless and controlled. And very little resistance is felt.
However, most pianos, if not all, unless specifically requested are set up to met the demands of general populace and not the concert artist.
It takes a highly skilled technician to do a "concert" regulation, but if you expect to play well, the piano must be right & of course we have to have our bodies and minds in shape as Alan talks about.
From my understanding, Horowitz had his piano fully regulated before each concert. And that's what it takes: an instrument that will give back, what is given to it.
Bob t