Action

The piano action mechanism (also known as the key action mechanism or simply the action) of a piano or other musical keyboard is the mechanical assembly which translates the depression of the keys into rapid motion of a hammer, which creates sound by striking the strings. Action can refer to that of a piano or other musical keyboards, including the electronic or digital stage piano and synthesizer, on which some models have "weighted keys", which simulate the touch and feel of an acoustic piano. The design of the key action mechanism determines the "weighted keys" feeling; that is, the feeling of the heaviness of the touch of the keys.[need quotation to verify]"A professional pianist is likely to care most about the piano´s action, because that is what controls its responsiveness and relative lightness--or heaviness--of touch. Roughly speaking, a piano´s action is light when its keys fall easily under the fingers, and heavy when a noticeable downward thrust is required. The action, in short, is what makes a piano playable or not to an individual musician."