Apple Logic Pro 9 - Manual (Page 789)

As you are unlikely to have the technology required to make binaural recordings, your
best chance of simulating binaural signals is by processing the sound signal on playback.
This is known as the head-related transfer function (HRTF), which approximates the change
that a signal undergoes on its way from the source to the eardrum.
Working with MIDI Channel Strips in the Mixer
This section deals with the MIDI channel strips of the Mixer, as well as those of the
GM Mixer (see
GM Mixer Objects ).
The MIDI channel strips work as remote controls for the mixing parameters of your
MIDI-controlled sound modules and synthesizers, such as volume and pan.
Note: The controls send MIDI control change messages. They do not control any audio
signal flow within Logic Pro.
789 Chapter 27 Mixing