Steinway's Accelerated Action
The touch of a Steinway is the most responsive and sensitive of any piano made. This is not opinion. It is a fact that results from the way the instrument is designed and manufactured. In fact, Laboratory tests have proven that the keys on a Steinway piano can repeat 13% more quickly than the keys of any other piano. The same features that allow for the faster repeat also provides a much more sensitive, responsive keyboard, an aspect that can be appreciated even by beginning pianists.
The Accelerated Action® is found on all American-made Steinway grand and vertical pianos. Lets take a quick look at how it works.
The Accelerated Action comprises two design elements:
1) Balance Rail Bearing
The balance rail bearing, as you can see in the Steinway grand action photo, is a rounded felt-covered piece of maple. The balance rail bearing is the fulcrum on which the key pivots. Only the Steinway incorporates a rounded surface; other brands have flat rail bearings. Why is this important?
Scenario 1: Imagine an eight-foot by ten-inch wood plank balanced on a flat piano bench. It's no problem to place the plank so that it balances. The plank can be slightly moved one way or the other without either end touching the ground.
If you place your hand on one end and press very lightly, the plank might bend a little but the other end will not move. As you gradually press harder and harder, the other end of the plank will eventually move, but only after you have applied considerable pressure.
Scenario 2: Now imagine the same situation but with a round surface on top of the flat bench. In this case the plank moves easily (friction free), and it is somewhat difficult to balance it; once balanced, pressure on either end will cause the opposite end to move.
This principle underlies in every Steinway action. The benefit is that the Steinway keys move friction free on the rounded balance rails. The key meets no resistance as you depress it or as it returns. This makes for the most responsive action possible.
2) The Method of Weighting The Keys
The second distinguishing factor in touch is the weighting of the keys: Larger weights are placed closer to the balance rail bearing, causing the keys to return faster than they would with other weighting methods.
If the secret to a responsive action is a round balance rail bearing, why doesn't every piano manufacturer incorporate this feature? In one word: Time.
Because the Steinway action has a much more sensitive fulcrum than actions of other pianos, all other action-related refulation is also more sensitive.
The weigh-off process (lead weights are put in the keys to meet downward and upward pressure requirements) becomes very sensitive indeed, to the point where every key found on Steinway pianos is individually weighed off - a remarkably time consuming process.
Steinway, of course, is happy to put in the extra work; especially the result is the most responsive piano action in the world. As the founding credo states "Build the best piano possible, sell it at the lowest price consistent with quality."