The piano action is made up of over a thousand moving parts, mostly made of very small pieces of wood. These parts are hinged by tiny pins cushioned by felt and anchored with hundreds of small screws. The piano also contains a few hundred springs of various sizes. The proper alignment, spacing, and resistance of the action parts is refered to as regulation. 

Due to natural shrinking and warping of wood and the compression of felt, the piano's regulation will drift over time. When the piano's regulation is off (meaning the parts are no longer aligned and cushioned correctly), the piano's performance potential will suffer greatly.

Common symptoms of poor regulation are bad or uneven tone due to hammers not striking all strings evenly, decreased dynamic control (the ability to play loudly or softly), unevenness of touch, poor repetition, and an assortment of unpleasant noises. To maintain it's highest level of performance, a piano should be fully regulated every 10 years. When a piano is fully regulated, the key height is reset and all the keys are leveled. Then all the action parts are realigned to the strings and themselves, making sure that all parts are hinged at proper tension and all springs are set at the correct strength. Because a distance of 1/32nd of an inch is very relevant to the piano's performance, properly aligning all the action parts is a very time consuming process.Northeast piano service offers a full regulation service as well as touch up regulations which can greatly improve the piano's performance in a number of hours.