Disklavier

Some clarification here -- "analog MIDI"?  There's no such thing.

The MIDI signal that you apply to a MIDI 5-pin DIN connector is digital.  The
signal has two discrete values and changes at a rate of 31.25 kbaud per second. 
The MIDI channel of a computer sound card or a MIDIMAN interface changes digital
data of one format to digital data of another format.  No analog data are
involved.

"Analog" describes a signal that is continuous in time and can take on a
continuous range of amplitude values.  You will not find MIDI information
carried by an analog signal.

CDs contain digital data only--not analog data, despite the fact that you are
accustomed to hearing music from a CD.  When the digital data of a CD is
processed and applied to D to A converters, amplifier, and speaker, you will
hear sound--music, if that's what the digital data represents, or clicks and
buzz, if MIDI data were represented.

The left and right channels of an audio CD are encoded into a single data stream
and upon playing are separated into Left and Right data streams by a processor
in the CD player.  The separated Left and Right data are then applied to
separate D to A converters to form stereo audio.  It would be perfectly
plausible to apply only the Left data to a D to A converter to produce audio,
and the Right data to a device that would convert that data to a MIDI signal. 
If you listened to such a CD on a CD player, you would expect to hear music on
the left channel, and buzz on the right.
-- 
Robert Welcyng
Anchorage, Alaska