The Concert Grand Reproducing Piano
By Bob Taylor
On going discussions regarding the use of reproducing pianos in large concert settings have been most interesting. Various contributors have shared an amazing number of experiences of this type to reveal that it is perhaps not so rare an event as one might presume. I have been involved in at least four of these events, and find the experiences rewarding. But my prime reason for writing today is to discuss the concert grand reproducing piano.
Several recent articles advance theories that special roll coding is required to make the concert grand play correctly. I choose to take partial exception to those theories. It must be remembered that if a piano plays a concerto with orchestra, that the piano must play extremely loud to be heard in certain passages. If that same piano and roll were to be transferred to the ordinary living room, the results would not be very musical. To begin with, the orchestra just won't fit into the living room. So in the case of these special concert demo rolls, yes they are coded differently. They are coded extra loud. The reason for the different coding is not the piano or its size but rather the intended LOCATION of the performance.
To fill the concert hall with fortissimo music is beyond the capabilities of the home reproducing piano regardless of its size. My experience shows that sustained stack pressures must remain above 85 inches vacuum even when rapid, large chords are played. Actually, 100 inches of vacuum is desired. To develop this kind of power, special pumps were fitted into the reproducing pianos. In the Duo-Art, the system was straight forward. Aeolian simply added a second pump. One pump was used exclusively to drive the stack and the second pump was used for the roll drive and control functions. Few of the these Steinway DR's exist today, but those who know Chicago's Kay Harmes from the early years of this hobby are familiar with his original two pump Steinway model DR.
My personal experience is stronger with the Ampico concert grand. I have restored two of these instruments. The Ampico achieves its greater pump power by turning the pump at double speed. A second drive pulley is attached in tandem to the pump. Two standard Ampico motors simultaneously drive the pump. The drive motors have large three inch pulleys. Since there is adequate space for components, the factory actually put four motors in the piano. Two are AC motors and two are DC motors. The demo piano needed only to have the belts hooked to the correct motors to accommodate various stage currents.
The pump is equipped with a devise to override the normal spill valve. Special logic devices sense when the Ampico step intensities call for sustained fortissimo. When that occurs, the pump stops spilling at the normal 35 inches and rapidly changes to about 85 inches of vacuum. This change is controlled only by the step intensities and the crescendo devices have no control in triggering this higher pump output.
Almost all Ampico rolls from about 1920 through the end of "A" coding are able to correctly control this special concert pump. Some "B" coded rolls do not work too well.
Other interesting extra features of the Ampico Concert grand are the ability to instantly stop or start the roll by controlling the vacuum to the roll drive. A special valve could be controlled remotely or the from the drawer "repeat" switch to stop and start the roll drive. An additional vacuum regulator smoothed out the extreme pump changes in the supply to the roll drive and other drawer components. The remaining differences all are reliability type devises to insure a trouble free performance. The first concert instrument that I restored had all components intact. It is pictured on page 290 of the Bowers "Encyclopedia".
One last comment about the special Duo-Art rolls intended for concert use. In his writings, Doug Henderson stated words to the effect that they would not play on an ordinary Duo-Art--just rewind due to the different tracker scale. That may be true, but some of the rolls are coded with a "rewind" hole at each position where the roll must be stopped. The rewind hole, on the Concert Grand, is "teed" to both the "rewind" and "repeat" valves. Thus when it is time to stop the roll, the transmission is thrown into neutral, and the pump continues to run. When the conductor is ready for the roll to resume, he pushes a button that blocks the "rewind" tube and the transmission is immediately shifted back to "play" since the rewind hole is open, where the roll stopped. This is a very simple scheme and it works quite well. I have a small valve setup that enables this system on any piano in less than five minutes.
BobTaylor
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(Message sent Thu 3 Apr 1997, 04:09:49 GMT, from time zone GMT-0600.) |
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