I have no doubt that Bernt Damm found an error in the split point in
his piano as he described in MMD 031116.  But there is still confusion
about where the real split point is supposed to be.  In the three major
systems, none has a balanced bass/treble division.

Using middle "C" as note 40, we find that :

Duo Art splits at 43/44, D#/E,
  Total Bass notes = 39, Total Treble notes = 41
Ampico  splits at 44/45, E/F,
  Total Bass notes = 42, Total Treble notes = 41
Welte   splits at 46/47, F#/G,
  Total Bass notes = 43, Total Treble notes = 37

If, during original construction or rebuilding, a division error is
made, the music will be affected.  The most obvious will occur when a
single note melody line is played louder than accompaniment.  When the
melody note plays on the wrong division side, it will sound too soft.

The Duo-Art system with an external bleed strip will have other issues,
also.  If the bleed division does not match the stack division, the
affected valves will respond either too fast or too slow, depending on
the situation.  Poor repetition of the note will be the most obvious
characteristic.

For those who seek to make their reproducing pianos play more than one
format, part of the modification involves creating a floating stack
division at the crossover point.  In the case of the Welte/Duo Art
combined system, notes 44, 45, and 46 must be switchable between the
bass and treble divisions.  I do not advocate such modifications.

The bass treble stack division issue is confusing at best.  Rebuilders
must be careful not to assume the division they find is correct.
Thorough bench testing is the best insurance that everything is
correct.

Bob Taylor

 [ Does a definition of "correct" exist?  It's reasonable to assume
 [ that Duo-Art systems manufactured in New York were configured to
 [ properly play the Duo-Art rolls edited in New York.  Could we make
 [ the same assumption about Duo-Art pianos and rolls produced in
 [ England?  Is there evidence that the British and American roll
 [ editors were aware of the ambiguous 'E' at the split point and
 [ applied expression coding compatible to both systems?  If so,
 [ then both split points are correct and any Duo-Art piano can
 [ play any Duo-Art roll.  -- Robbie