Hi All,  One aspect of this conversation that hasn't been addressed
is the striker pneumatic cloth.  As most rebuilders know, the cloth
Aeolian used was extremely supple.  So, even if the replacement cloth
is only 5% stiffer, the performance of the mechanism will be diminished
at low intensities.

This becomes a problem when we draw conclusions based on the performance
of different pianos.  There's no way to know for certain who is right
or who is wrong because the tests are not scientifically controlled.
However, since we have the manuals that were written by the manufacturer,
it should be a simple matter to determine exactly what should happen
under a variety of circumstances.

And, if we can't achieve the results described in the manual, do we
really need to second guess the manufacturer?  Or might it be more
realistic to question the quality of the materials that were used in
the restoration?

Here's my thought.  We do the best we can with what we have at our
disposal.  As has been correctly noted, we might have to make slight
changes in various settings to accommodate our choice of replacement
materials and rebuilding techniques.  And while our aim should always
be perfection, I believe it's equally important to understand and
accept that we don't have the same materials and we don't use the same
techniques that the manufacturers used almost 100 years ago.

Also, one has to wonder how much latitude the quality control inspectors
had when these machines came off the line.  I'd say there's a pretty
good chance that most of them were not what we would call 'perfect'.
And I wouldn't be at all surprised to learn that they made slight
changes to deal with a variety of 'imperfections' rather than gut the
machine and start over.

A copy of the page that relates to the Accompaniment Zero Setting, Test
No. 7, is located at  http://www.musicrolls.com/duo-art/d-a23-25.jpg 
It also bears noting that at no place during Test 7 is more than one
note being activated at a given moment in time (D/A Test Roll #3).

It's also interesting to note the wording that's used to explain what
should happen as the test is performed.  "On the first run, notes
should play very softly (that's subjective), and on the next run, most
of them should miss or skip."  Why didn't they say, "none of the notes
should play?"  Then the test goes on to the third run, and it says that
the test "is similar" to the first.

In actuality, it's identical, but here's where the wording gets almost
bizarre.  It says, "If, on the second run, all notes should strike full,
the setting is too loud and must be softened".  Isn't that obvious?
They just got done telling us "most of them should miss or skip."

Further, and based solely on the information presented in the Service
Manual, one can objectively surmise that a three-note chord is not
supposed to play at Accompaniment Zero.  Still, given the subjective
nature of the wording in the manual, if the sustain pedal were 'On',
the chord might play 'really' softly.  (Based on the premise that
'really softly' is softer than 'very softly'...  ;-)

And what would happen if the valve clearance were reduced by 0.002"?
In fact, when we get down to the lowest playing levels, virtually
everything that has to do with the playing of the notes has a lot to
do with how they will perform.  As my mentor once told me, "The closer
we get to perfection, the easier it is to spot imperfection."

So, who can say for absolute positive that a three-note chord is 'not'
supposed to play at Accompaniment Zero?  My opinion is, if it's really
that important to hear the chord, raise the Accompaniment Zero level so
that "most of them (should) miss or skip" on the second run.

After all, how many is "most?"  51%?  60%?  80%?  Surely it's not 100%,
or they would have said "_all_ of them should miss or skip".

In closing, I say, "Please the customers.  That's my first rule!  They
pay the bill!"

Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA