Apple Logic Pro 8 - Manual (Page 822)

822 Chapter 35 Working With Surround
The separation square is visible if the extended parameter section is open. If the
extended parameter section is closed, it will remain visible if any of the separation
values does not equal 1.00. It also stays visible when the default values are reached by
editing the square graphically. Closing the extended parameter section (with all
separation values at 100%) will make the square disappear.
You can Option-click on the value field or sliders shown in the extended parameters (or
on the separation square lines) to reset them to default values.
Note: In 7.1 ITU surround formats, the Separation of Left Middle and Right Middle is
determined by the average separation value of the Front and Rear channels.
Stereo to Surround Panner
If the source input is set to stereo, the Stereo to Surround Panner appears. It is similar
to the Mono to Surround Panner, but features three pan pucks: a puck for the L(eft)
signal, a puck for the R(ight) signal, and a third puck, that controls both the L and R
pucks as a group. It also offers a Spread field in the upper right corner, which controls
the stereo width of the signal.
Moving the L or R puck in the surround field will move the second puck in a
symmetrical fashion. Dragging the third puck moves both the L and R pucks, while
maintaining a given spread.
A left/right movement changes the angle of both, an up/down movement changes the
diversity. The circular bars around the panner indicate which speakers will carry the
respective signal source; the closer to the center a puck is moved, the wider the
corresponding bar gets (the greater the diversity, in other words).