Fader functions: midi events – Apple Logic Express 8 User Manual
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Chapter 38
Working in the Environment
Text Fader Range
The Range parameter determines the number of names that can be entered into a text
style fader object. If you set a text style fader’s range to 0, 1 you can only enter two
values.
You should always set the minimum necessary range for a text fader, as this saves
memory. In any case, remember that the first name corresponds to the lowest value in
the range (not necessarily 0), and the last name corresponds to the highest value (not
necessarily 127).
If you force a text fader to a value outside its range (with MIDI input) it will display “---”
for values below its range and “+++” for values above. The one exception is when the
fader’s range is 0/1: In this case, all values above 1 will display the name for value 1.
Fader Functions: MIDI Events
Each fader has an Input and an Output definition.
 The Input definition determines the types of MIDI events that can remote control the
fader (the event types it reacts to).
 The Output 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).
 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 objects,
such as Faders (and Transformers) always provide for 3 bytes, with the second byte
being discarded when these special, 2-byte messages are received.
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 if the
fader is being remotely MIDI-controlled, by the incoming MIDI event.