Disklavier

This ties into the difference between the Disklavier Pro and the standard
Disklaviers (including the Mark III series). My understanding is that the
regular Disklaviers can be calibrated via a service mode procedure, so
that the drive system configures its table of how hard individual notes
must be struck to achieve certain velocities. This sets up the internal
tables of how hard individual solenoids must strike each note to produce
certain hammer velocities. Also, to some degree, the standard Disklaviers
self-calibrate as they play. For example, the system is instructed to
strike a note at a particular velocity. For each note struck, it measures
the final resulting hammer shank velocity. Based on the measured data, it
knows whether it struck too hard or too softly relative to the requested
velocity, and can adjust the internal table to try and play that note more
accurately next time.

If my understanding is correct, the Disklavier Pro mechanism differs in
that it has a closed-loop feedback system that permits the hammer position
to be monitored _continuously_ while a note is being struck and the
solenoid duty cycle adjusted on the fly to compensate for any variation
from the velocity requested. Thus, the Disklavier Pro plays more
accurately because the closed-loop system enables it to play each note
with the exact velocity requested (or very close to it) instead of firing
the solenoid with a best guess and working to "get it right next time",
the way the standard Disklaviers function. Because of the improved
accuracy of the Pro's drive mechanism, the system supports 10 bits of
velocity data (1023 levels) instead of the 7 (127 levels) supported by the
non-Pro units. The pedal system employs a similar feedback system and on
the Pro is capable of reproducing 128 different positions for each pedal
vs. 16 on the non-Pro units.

If someone from Yamaha could confirm this description is correct or offer
additional information, I would appreciate it. I have spoken with several
dealers and none have been given much technical information about either
system.


On Wed, 16 Jan 2002, vincentdeleur wrote:

> The hammer sensors are working together with the key sensors, together they
> measure the movements of hammer and key to have the best information of
> playing.
>
> Vincent de Leur
> Yamaha Music Netherlands
>
> -----Oorspronkelijk bericht-----
> Van: crayton1999 [mailto:david.grubb@...]
> Verzonden: woensdag 16 januari 2002 18:16
> Aan: disklavier@yahoogroups.com
> Onderwerp: [disklavier] Disklavier Hammer Sensors
>
>
> Hello from Southern California,
>
> I am new to this wonderful technology of computer aided pianos and
> was wondering the purpose of the 'hammer sensors'. Thanks in advance.
>
> Best regards.....
>
>
>
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>
> To Post a message to the group, send it to:   disklavier@...
>
> To Post a private message to Todd Muncy, the group's founder and moderator, send it to:
> disklavier-owner@...
>
> To reach our group's web site go to:
> http://Yahoogroups.com/group/disklavier
>
> Todd's family web site was completely rewritten in June 2001 and contains some fun disklavier content and links to midi sites among other things, The url is:
> http://MuncyFamily.com
>
> THINKING OF LEAVING THE GROUP?
> If you are thinking of unsubcribing because you are getting too much mail, go the the web site and change your email delivery option instead.  That will fix the problem, while maintaining your access to the group.  If you insist on leaving us completely send a blank email to:
> disklavier-unsubscribe@...
>
> Know someone who wants to join?  Have them send a blank email to:
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>