The piano's action and why it needs maintenance (regulation)
A well-maintained, regulated piano is dynamic. It is able to go from delicate, soft passages to powerful crescendos seamlessly. Each key should feel and respond the same as its neighboring keys. While regular tuning keeps your piano sounding great, routine action regulation is important to maintain your piano’s consistent feel and dynamic range.
When a piano leaves the factory, each of its action parts (there are approximately 8,000 of them) is adjusted to a tolerance of a few thousandths of an inch. Because the wood and felt parts of the action change dimension due to humidity and wear, the action must be serviced occasionally to maintain its responsive qualities.
All upright and grand pianos need periodic action regulation to perform their best. The frequency of regulation depends on the amount of use, the instrument's quality, age and condition. Pianos that have never been regulated may require a day or more of labor to get them regulated. New pianos require regulation after their first couple of years due to settling and compacting of parts.
I offer different options on maintaining the action’s regulation depending on the customer and the piano. I bill out on half-day and full-day rates where I do as much in the time allowed to get the piano performing as well as possible. Once a piano has been fully regulated it can be kept “in regulation” with a two or three hour session once every two or three years.
Benefits of regulating your piano's action:
The piano is capable of being played faster, louder and softer
Your piano will retain "like new" touch
Prevents wear on action parts.
The Concert Pitch Piano Services site has excellent single note diagrams of the workings of a
grand action and upright action showing the complex and amazing piano action.