Surround Panner parameters in Logic Pro for Mac

Surround field

A circular grid, comprising four concentric circles divided into eight 45-degree segments, represents the surround field from above with the listener in the center facing forward.

When you use a surround format with overhead channels, you can select one of two modes, Planar or Spherical. Each mode provides a different visualization of the surround field, which also results in a different signal distribution when you move the puck around.

• Planar: A flat circular plane shows the panning position, referencing only the left, right, front, and back positions. This is the default display for surround formats without height channels.

  Note: Moving the puck to the center increases the diversity to a maximum value of 1. The source signal now plays through all speakers. In surround formats with height channels, the sound is also played through the height speakers, even if the Elevation value is set to 0.

• Spherical: A circle representing a dome shape viewed from above can also indicate the height position of the sound source.

  Note: Moving the puck to the center increases the elevation value to a maximum of 90°. The source signal now plays through all height speakers but none of the ear-level speakers.

Speaker icons

A number of speaker icons surround the circular grid. Each speaker represents an output channel, such as left (L), center (C), right (R), or left surround (Ls). Blue speakers represent ear-level channels, and green speakers represent overhead channels. The number of speaker icons and their position is determined by the surround format selected in the Audio project settings. See Overview of surround formats.

Click a speaker to turn the respective output channel on (solid) or off (outline). This signal is then distributed to the remaining speaker channels, thus changing the surround output format. Turning off a speaker icon on the Surround Balancer only mutes that speaker channel without changing the surround output format.

Center and LFE level offset

You can apply a level offset to the center channel and LFE channel (ranging from +6 dB to –82 dB) or mute them completely. Drag the slider or field to adjust the level (Shift-drag for finer resolution), or double-click a field and enter a value numerically.

• Center Level slider: Adjust the level of the center channel. The controls are inactive if the center speaker icon is turned off.

• LFE Level slider: Adjust the level of the LFE channel. The abbreviation stands for Low Frequency Enhancement or Low Frequency Effects, as the LFE output is most commonly sent to a subwoofer.

  Tip: If you want only low frequency signals to reach the LFE channel, insert a Channel EQ in multi-mono mode into the surround master channel strip. Use this to control the LFE (or subwoofer) output. A lowpass cutoff frequency of 120 Hz is standard for most surround apps. See Configure multi-mono effects.

Pan puck with diversity and angle display

The dot in the surround field, the pan puck, represents the position of the sound source on that channel strip relative to the listening position (in the center of the surround field). Drag the pan puck to position the sound source and, therefore, determine the signal routing. Moving the puck toward a speaker icon increases the level sent to that output channel.

If the input format is mono or stereo, the surround field has a dark ring around the circular grid, showing a green line that can span from a dot to a full 360-degree circle. It corresponds to the position of the pan puck and shows the angle (the position in the 360-degree surround field) and the diversity. The diversity is 0 if the pan puck is placed directly at a speaker icon, which means the sound source is only routed to that speaker channel. When you move the puck toward the center, the outer ring expands, indicating to what other speaker channel the sound source is routed.

You can modify the movement of the blue dot with these functions:

• Press and hold the Command key while moving the puck to lock the diversity value.

• Press and hold the Control and Command keys while moving the puck to lock the angle value.

• Option-click the green puck to reset the angle and diversity values.

Numeric values

In addition to moving the pan puck, you can adjust the numeric values of the following parameters by dragging the field or double-clicking it and entering a numeric value. The position of the puck changes accordingly.

• Angle: Change the circular position of the puck and, therefore, the position of the sound source in the surround field relative to the listening position.

• Diversity: With a value of 0, the pan puck is positioned at the outer ring, routing the sound source only to that speaker channel (or two adjacent speakers). Increasing the value routes the sound source to more adjacent speakers indicated by the outer ring. The maximum value is 1, also called super mono, when a sound source is playing through all speakers.

• Amount: If the format of the channel strip is surround, the Amount parameter is shown instead of the Diversity parameter. Increasing the number from its default 0.00 value (the unaltered surround signal) moves the puck toward a speaker (depending on the angle value), reducing the signal level of the opposite speaker channels.

• Elevation: Adjust the position of the sound source between ear-level speaker channels (0°) and height speaker channels (90°). The parameter is only available if the current surround format has height speakers.

  Note: You have to select the Spherical button to get a visual representation of the height position.

• Spread: This parameter is only available if the format of the channel strip is stereo. It determines how wide the left and right channels are spread apart (similar to stereo width). A value of 0° folds both channels into mono; 90° would be a typical stereo spread between a left and right speaker. A maximum of 180° would put the stereo signal in the left mid and right mid channels with an angle of 0°. A negative value represents a left-right channel swap.

Separation parameters

The Surround Panner shows the Separation On/Off button with three parameters. These controls are not available for surround channel strips or if you’ve selected a surround format with height channels. When the Separation button is turned on, the three parameters become active, and an orange separation frame appears in the surround field.

Drag the corners or edges of this separation frame to change its shape or edit its corresponding numeric values. As you decrease these parameters from their default values of 1.00, the separation frame changes (to a trapezoid or rectangle) in the surround field, providing a visual representation of how changes in these values affect the surround panning. Option-click the value field for each parameter to reset them to their default values.

Separation is similar to cross-feed between a speaker pair. For example, with a maximum separation value of 1 between the left and right output channels, a signal routed to the left output channel only plays through the left speaker, and signals routed to the right output channel only play through the right speaker. Reducing the separation value spreads the signals from the original output channels to the opposite speaker channels. With a separation value of 0, signals routed individually to the left and right output channels are playing equally on both speakers.

• Separation XF: Applies to the Left and Right (front) channels. Reducing the XF value from 1.00 down to 0.00 mixes the right signal into the left channel, and vice versa, until both channels output the same signal.

• Separation XR: Applies to the Left and Right Surround (rear) channels. Reducing the XR value from 1.00 down to 0.00 mixes the right surround signal into the left surround channel, and vice versa, until both channels output the same signal.

• Separation Y: Affects the mix relationship of the front and rear channels (in front of or behind the listening position). It mixes the Left/Left Surround and Right/Right Surround channels. When the Y value is set to 0.00, the front and rear channels output the same signal.

Legacy controls

The following options appear only in projects mixed in surround and saved in Logic Pro versions 8.x to 9.1.6.

• Level Compensation pop-up menu: Select the surround pan law for stereo-to-surround and mono-to-surround channels.

  • Unity gain at speaker: The default setting for mono-to-surround and stereo-to-surround channels. All new projects and projects imported from Logic Pro 9.1.7 or later follow this pan law.

    A mono signal panned hard left of a stereo output with X dB gain will do the same if panned hard left with a mono-to-surround panner. A stereo signal panned hard left and right with X dB gain will do the same if panned hard left and right with a stereo-to-surround panner.

  • Unity gain at mid-point: This was the default setting used for Logic Pro versions 9.1.4 to 9.1.6. Projects imported from these Logic Pro versions will adopt the Legacy pan law. You can choose a different pan law from a dialog or this pop-up menu.

  • Legacy (Pre Logic 9.1.4): This was the default setting used for Logic Pro versions 8.x to 9.1.3. Projects imported from these Logic Pro versions will adopt the Legacy pan law. You can choose a different pan law from a dialog or this pop-up menu.