Apple Logic Pro 9 - Manual (Page 1173)

• A number of speaker icons surround the circular grid. You can change the channel
surround format directly in the Surround Panner window by clicking the speaker icons.
This activates or deactivates the respective channels. Blue speakers indicate active
channels, and gray speaker icons denote inactive channels.
• The blue dot controls the routing of the signal to the speaker outputs. You can drag
the blue dot in the surround field.
The movement of the surround position (indicated by the blue dot) is made easier with
these functions:
• Hold Command to lock diversity.
• Hold Command-Option to lock the angle.
• Option-click the blue dot to reset angle and diversity.
Level Controls
The Center Level slider and field determine the volume relationship of the (front) center
channel—typically used for dialogue in film and TV productions.
The LFE Level slider and field control the volume of the LFE output. The abbreviation
stands for Low Frequency Enhancement or Low Frequency Effects, as the LFE output is most
commonly sent to a subwoofer channel. The use of a subwoofer speaker is not mandatory.
Tip: If you only want low frequency signals to reach the output, insert a multi mono
surround EQ into the surround master channel. Use this to set the LFE (or subwoofer)
output. A cutoff frequency of 120 Hz is standard for most surround applications.
Separation Controls
The sliders in the lower section of the Surround Panner window determine the amount
of separation between various channels. As you alter these parameters away from values
of 1.00, the separation square changes (to a trapezoid or rectangle) in the surround field,
providing visual feedback on how the channel is being affected.
• Separation XF: Applies to the Left and Right (front) channels. Reducing Separation from
1.00 down to 0.00 mixes the right signal into the left channel, and vice versa, until both
channels output a mono signal.
• Separation XR: Applies to the Left and Right Surround (rear) channels. Works as above,
for the surround speakers.
• Separation Y: Affects the mix relationship of the front and rear channels (in front or
behind the listening position, in other words). It mixes the Left/Left Surround and
Right/Right Surround channels. When Separation Y is set to 0.00, the front and rear
channels output in mono.
1173 Chapter 39 Working with Surround