The Steinway Accelerated Action

Steinway’s accelerated action was introduced in 1934 amid some fanfare. It was reported in the Nov.-Dec. Presto –Times publication of 1934 that Polish born concert pianist Josef Hofmann (1876-1957) once came to Steinway Hall in 1932 to ask if they could make their actions “more sensitive” and even “more responsive”.  Well that request was supposed to have given the impetus to the creation of what we know as the Accelerated Action. That little story may have been put together after the fact though, because the half-round key bearing, which is an integral part of the Accelerated Action was patented in 1931. The idea apparently had been worked on well before Hofmann’s request was received.

Be that as it may, the Accelerated Action was created by Frederick Vietor to improve the response of the piano action. Times were not good for the sale of pianos during the early thirties. Times were not good for the sale of much of anything during that time. Something that could create a renewed interest in the piano would be welcomed, however small it might be. Perhaps this was the impetus for the invention.

Here are the claims:

      1)      The new Accelerated Action is quicker by an average of .02 of a second at a fortissimo blow. This was measured from the time the finger begins to depress the key to the time the key and hammer returns at rest. The total time that they used from the beginning to the end of playing the key was approximately .15 of a second. The tests were done using high-speed photography and they determined that the return of the key was .02 of a second quicker.

      2)      Because the key and hammer return is that much quicker, the hammer drops completely away from the strings after contact by the same .02 of a second faster.

      3)      Less force is required to play pianissimo because the inertia is less in the key, due to the placements of the key leads closer to the key’s fulcrum. Placing the leads closer to the fulcrum requires more lead, but decreases inertia in the key by 15% on average.

      4)      Measurements of internal friction with the Accelerated system averages 11% less friction and friction is more uniform, which makes fortissimo playing slightly speedier (less friction) and more precise (more uniform friction).

Testimonials of the new Accelerated Action from some artists:

      1)      Vladimir Horowitz: “The new Steinway accelerated action is a marked improvement on the action of a Steinway piano. It makes a perfect action still more perfect.”

      2)      Josef Hofmann: “The seemingly impossible has been achieved. The Steinway piano has been improved upon. The new Steinway accelerated action has done it. The invention not only facilitates and enhances tone production but also permits greater precision and speed. I, therefore, take pleasure in recommending this new creation to all who are interested in the art of piano playing.”

      3)      Sergei Rachmaninoff: “This is to tell you that I consider the new Steinway accelerated action a great improvement, and that I have found your pianos more perfect during the past two seasons than ever before.”

      4)      Mischa Levitzki: “I consider your new Steinway accelerated action the greatest improvement achieved by the piano industry in many, many years. I venture to predict that it will have a far-reaching beneficial effect upon the whole of piano playing, both professional and amateur. For, with greater smoothness and responsiveness of your new action, the player will not only be able to carry out difficult passages with greater ease, but will also be able to produce a more beautiful tone, thereby getting even more inspiration from the matchless Steinway tone than ever before. I rejoice with you in your new achievement.”

What is the Accelerated Action that Vietor invented? It consists of two parts. One, the aforementioned half round key bearing found under each key’s fulcrum, slightly less than one-half inch in width and about one-quarter of an inch high (made by cutting a half-inch dowel in half length-wise, and then cutting the lengths into pieces which fit under each separate key), and the curved portion covered with fairly thin white wool cloth for noise reduction. These take the place of the traditional round flat felt punchings normally found under piano keys.

The other part of the Accelerated Action design is the placement of the key leads. The accelerated system called for a specific way of leading the keys. The first key lead was to be placed as close to the key’s fulcrum as possible and then as more leads were needed, they would be added as close to the previously placed key lead as possible, and so on until the desired touch weight was achieved, rather than the traditional method of adding the first lead as far away from the fulcrum as possible, and then adding leads (as needed) as close to the previously placed lead as possible, and so on until the desired touch weight was reached.  Either way, they would have to weigh off each key of the action to the same touch weight specifications. The Accelerated Action lead placement gave slightly less inertia for the player to overcome at the key because, as was mentioned, the weight was positioned closest to the fulcrum. This lead placement was scientifically deemed to have enough of an effect on lessening the inertia at the key to be included in the design. The hammer accounts for most of the inertia in the action, but decreasing the inertia at the key did have an overall advantage of a slightly lighter feel when playing fortissimo. 

As Steinway has recently abandoned that method of leading and has returned to the “traditional” leading method, they have tacitly admitted that the Accelerated Action didn't really need the special leading pattern, or at least the additional work of putting more lead in, did not a difference make. They continue to use the half-round key bearings however.