Disklavier

I need some help interpreting the damper pedal "half point 
adjustment".  I'll apologize in advance as I'm guessing that this is 
going to entail a bit of a lengthy explanation.

I have a Disklavier MX1Z upright and like many others on this forum, 
I do some of my own DKV calibration.  This is particularly true for 
the DKV pedal regulation (adjustment/calibration procedure) that I 
became quite familiar with through a recent exercise to correct a 
thumping problem I had with the damper (loud) pedal. I'm happy to 
report that the pedal thumping is gone!

Although I've become comfortable doing most of the pedal adjustments 
(damper/loud and shift/soft), I'm trying to get my mind around 
the "half point position" that's part of the damper (loud) pedal 
adjustment procedure.  Although this procedure is simple, I find it 
subjective, fundamentally because I haven't yet developed a solid 
basis for the required adjustment. 

At the end of the DKV damper pedal calibration (maintenance mode 
#3), the loud pedal half point starts automatically.  The DKV will 
play a C major chord and, following this, DKV hammer #88 (DKV note 
C7, i.e., C note, 7th octave) will play once per second.  So what we 
get is the following repeating (60 bpm) pattern:

    C chord
    note C7 (hammer #88)
    note C7 (hammer #88)
    note C7 (hammer #88)
    note C7 (hammer #88)


The display on the DKV controller indicates, "ADJUST 1.5 sec AND 
PRESS [REC]". 

So far so good.

The objective of this procedure is to set the half point value so 
that the dampers silence the strings just as the 2nd time note #88 
is heard.  What I'm trying to ascertain is the degree of "silence" 
specified in this procedure.  

For my first attempt, I set the half point value such that the 
dampers were just starting to dampen the strings exactly when the 
2nd C7 note sounded.  However, when I later played a PianoSoft solo 
piano file, I found that there was too much sustain, i.e., the 
dampers were not engaging quick enough and the strings 
were "ringing" too much.  I played back a variety of solo piano 
pieces, both with continuous pedal data and ON/OFF pedal data, and 
came to the same conclusion.

For my second attempt, I lowered the half point setting such that 
the dampers were completely silencing the strings just as note C7 
sounded for the 2nd time.  This time, when I played a PianoSoft solo 
piano file, I felt the piano sounded too restrained on playback, 
i.e., the strings were being muffled too quickly and/or too much.

For my third attempt, I set a half point value that was a compromise 
between my first two attempts.  It now appears that I'm in the 
right "Ball Park".  However, if I understood the adjustment 
procedure better, I may be able to find the exact "sweet spot".

As it stands with my current setting (a half point value of 43 if I 
recall), I find that song playback is good for files containing 
continuous pedal, but I hear more sustain going on with songs using 
simple ON/OFF damper pedal data.  I'm guessing that this is the 
expected end-result and/or audible difference between continuous and 
ON/OFF pedal data.

So, with the forgoing as background, here are my questions:

1) Can anyone give me some perspective on how much "silence" is 
being specified by the half point adjustment?

2) Out of curiosity, why is the procedure entitled " half point" 
or "adjust 1.5 sec"? Is this to imply that the dampers should be 
engaging the strings around the midpoint between the 1st and 2nd C7 
note? 

3) If the 1st and 2nd notes are being used as a timing reference to 
make the half point adjustment, why are four notes sounded in total 
instead of just two?  I'm thinking there must be some significance 
to having the 3rd and 4th notes?

4) Any comments about the greater amount of string sustain during 
playback of files containing basic ON/OFF pedal data?

5) Can anyone confirm whether every time the pedal measurement 
program is run, it MUST be followed by the "keyboard measurement 
program" (maintenance mode # 5)?

In anticipation of some writing back to suggest that all DKV 
adjustments be left to a "qualified" DKV technician, I'll mention 
that I usually have my RPT (who is wonderful and also the local DKV 
tech) visit my piano anywhere from 2 to 4 times a year. 


Regards,

Robert