The expressiveness in piano music comes from your ability to reach both the softest pianissimo and loudest double forte. A well-regulated piano allows you to have that touch consistently across the keyboard.

A piano can lose regulation, and in this post we’re going to talk about how that happens and what grand piano regulation does to fix it.


The most common reason that a piano goes out of regulation is that the felt parts become compressed. After years of play, some of the felts become more compressed than others. Keys with worn felts are no longer able to reach that volume range. Because not all of the keys are worn the same, you lose consistency across the keyboard.

Now, a piano is regulated when it is built. But that doesn’t mean the piano will be well-regulated forever. High-end instruments may take a longer time to lose regulation than inexpensive pianos, but all pianos lose regulation eventually.


Regulation begins with removal of the piano’s action. Once the action is removed, we will take important measurements such as string height. Once the action is in the shop, we’ll begin regulation. There are several tasks involved in regulating a grand piano. Here are a few of them:

Capstan adjustment to raise and lower hammer height

Hammer height is the distance between the hammer and the underside of the strings. There is an optimal hammer height that allows for just the right amount of power when hammer meets string. Too little or too much distance in the swing is not desirable.

Leveling keys with leveling paper

Your piano’s keys should be perfectly level from one side of the keyboard to the other. Leveling papers are inserted to raise the keys by extremely small amounts to bring the keys level. We’re talking about a difference of perhaps .001″.

Letoff button adjustment

The letoff button releases the mechanism in a split second before the hammer hits the string. This is done so that the hammer is striking the key under it’s own momentum, not being jabbed into the string. We adjust the letoff button to make sure that that the hammers release as close to the string as possible. This allows you to play with a very light touch.

Adjustment of the repetition spring

Every key has a spring that helps the action “reload.” This happens just after a note is played but before the key even has a chance to rest. The repetition spring’s setting is crucial. Too much tension can cause a double striking hammer. Too little tension can result in a sluggish or even non-playing note.

These are just a few of the tasks that are required to regulate your grand piano. This is a meticulous job that requires repeated measurements and adjustments for a perfect outcome. The length of time this project takes depends largely on the condition of the action. If the action has not been properly maintained for a long time, it will take us longer to correct it.


A loss of regulation isn’t the only reason that a keyboard loses consistency. Many parts on your piano’s action wear over time. To get the best regulation, a piano’s action should be in good working order. For that reason, we recommend that you get any action repairs completed before regulation.