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