Apple Logic Express 7 - Manual (Page 186)

186 Chapter 5 The Environment
Fader Functions: MIDI Events
Each fader has an In and an Out definition. The In definition determines the types of
MIDI events that can remote control the fader (the event types it reacts to). The Out
definition determines the types of MIDI events the fader sends out. (A fader can,
therefore, convert one type of MIDI event to another).
Most MIDI events consist of three bytes. The first byte indicates the type and channel of
the MIDI event (a note on channel 3, for example). The second byte indicates the first
data value (the pitch of a note event, for example) and the third byte indicates the
second data value (the velocity of a note event, for example). A few MIDI events only
use two bytes (program change and aftertouch). Some, such as faders (and
transformers) always provide for 3 bytes, with the second byte being discarded for
these special, 2-byte messages.
Fader parameters are provided for setting the message type, MIDI channel and the first
data value. Note that the message type and MIDI channel are actually combined in the
resulting MIDI event. The second data value is determined by the fader setting, or in
the case of remote control, by the incoming MIDI event.
Here are the In and Out definition parameters:
Out (or In): defines the event type (use the pull-down menu shown in the diagram).
Channel (1 to 16): defines the MIDI channel of the event.
-1- (0 to 127): defines the first data byte of the event. In some cases, such as pitch bend,
this is an actual data value. In other cases (MIDI controllers), this indicates the controller
type (volume, pan, and so on, as examples). In other cases, such as aftertouch, this byte
is unused.
Here is the meaning of the -1- parameter and fader position for each of the In and Out
definition choices: