Disklavier

Does anyone know how to open the midi files contained in the Yamaha 
Disklavier E3 Sample Disc on a PC based sequencer program such as 
Cakewalk, in order to edit specific parameters such as velocity, volume, 
etc.


Windows Explorer shows the files as .mid files but I cannot get any 
sequencer program to open and play the files. They all say it is an 
incompatible format.


I would like to be able to adjust velocity and volume of various 
instruments for the particular acoustics of the room where my Disklavier 
with DKC-850 is located but am unable to do so.


Any help or advice would be most appreciated.


Sheldon Deluty