Regulation is done whenever we replace the felt under the keys, replace hammers, damper felts, etc.
In simplistic terms, it is adjusting the mechanism to perform optimally.
First, the height of the keys need to be determined.
To adjust the height of the keys, and to level them, you add or remove paper washers under the bkeys, on the balance rail, where the keys pivit.
To adjust the keydip, “how far the key presses down”, you add or remove paper washers at the front of each key, on the front rail.
Setting hammer blow distance, is done at the hammer rest rail in uprights. In grands, this is done by adjusting the capstan screws.
Lost motion is the motion that you feel in the keys, when you start playing. If there is lost motion, you will often feel a space in a key, before the key actually plays.
This is adjusted in the capstans, “upright”, or repetition lever height, “grands”.
When replacing the hammer rest rail felt in uprights, you can, to a certain extent, adjust the hammer blow distance, and elliminate lost motion in the keys.
Letoff “or escapement” is very important.
This is the adjustment that when the hammer is 2 millimeters away from the strings, the mechanism has to disengage from the hammer, so that the hammer travels on its own momentum for the last bit.
If we have no escapement, the hammer will block against the strings.
If we have too much, you won’t be able to play with preciseness, or fast repetitions.
In grands, there are actually a separate part in the mechanism called a repetition lever, which causes the jack to return quickly under the hammer again.
This is why grands, in general, have faster repetition than uprights.
They also have drop screws, to stop the travel of the repetition levers, which have to be set at the same time when the jack reaches the letoff button, and is about to trip the jack.
Back-checks catch the hammers halfway.
This happens when you play a key, but don’t release it immediately.
The hammer hits the string, and falls back, not all the way, but the backcheck catches it, to help you to play the key again.
The dampers have their own set of adjustments, but the most important adjustment, is that they should open, when the hammers’ travel is a third to halfway to the strings.
Adjusting the pedals:
The right pedal, “sustain pedal” has to be adjusted so that there is a bit of lost motion before the pedal rod engages the cross lever.
The other pedals could also be adjusted in this way, but we like to adjust them without any lost motion.
There are many more adjustments that we can talk about, but these are the basics.
If these adjustments are out, your piano will not play optimally, and will feel stiff, without any control, uneven, keys that are not perfectly level, and will frustrate beginners as well as advanced pianists.
Regulation, together with tuning and voicing “changing the tone of the hammers”, are critical for concert pianist, concert venues, recording studeos, etc.
Next time you book a tuning, ask your piano technician to look at the regulation of your piano.
We offer full regulation, as well as a touch-up regulation, depending on what your piano needs.