Audio Preferences in Logic Express

Audio preferences consist of the following tabs:  Devices, General, I/O Assignments, Sample Editor, MP3, and Reset.

Figure. Audio preferences.
To open Audio preferences
Do one of the following:
  • Choose Logic Express > Preferences > Audio (or use the Open Audio Preferences key command).

  • Click the Preferences button in the Arrange toolbar, then choose Audio from the pop-up menu.

Core Audio Device Preferences

Logic Express automatically recognizes any installed Core Audio hardware, and uses the default settings as defined in the Audio MIDI Setup utility (Applications/Utilities/Audio MIDI Setup). However, it can be advantageous to optimize the settings for your individual hardware setup, particularly if you use several audio interfaces or a multiple input/output device.

Figure. Core Audio Device preferences.
  • Enabled checkbox: Select this checkbox to enable the Core Audio driver.
  • System Memory Requirement display: Indicates the amount of free RAM required (outside of memory assigned to Logic Express). The requirement value changes as you alter the parameters described below.
  • Resulting Roundtrip Latency/Resulting Output Latency display: Displays either the resulting roundtrip latency or the resulting output latency for the current I/O buffer size. Click the display to toggle between the two values.
  • Recording Delay slider: Allows you to delay the recording of audio by a certain fixed value, helping you to compensate for any information delays that are caused by the audio driver.

    Note: You should not normally need to touch this parameter.

  • Universal Track Mode checkbox: Universal Track Mode is turned on by default. It allows you to play back stereo and mono regions on a single track. It should be left on.
  • 24 Bit Recording checkbox: When this setting is turned on, Logic Express can record 24-bit files. 20- or 24-bit recordings offer a significant improvement in the available dynamic range, but require high-quality peripheral components such as microphones and pre-amps, not to mention high-quality analog-to-digital/digital-to-analog converters.

    20- and 24-bit files use one-and-a-half times the disk space of comparable 16-bit files.

    Note: Turning on this parameter only makes sense if you are using a 20- or 24-bit interface.

  • Software Monitoring checkbox: This option allows you to turn Software Monitoring (listening to the actual input signal) on or off. In most situations, you should leave it on.

    Note: When Software Monitoring is on, the audio signal is processed via software, and a certain amount of audible delay (commonly referred to as latency) is inevitable.

    If you are listening to the recorded signal through your mixing console, or your audio interface supports hardware monitoring, you should turn this option off.

  • Independent Monitoring Level (for Record Enabled Channel Strips) checkbox: Select this checkbox to allow the use of an independent monitoring level for record-enabled audio channel strips. After record-enabling a track, you can adjust the fader to the level you want. The original level will be restored when you turn off the record-enable button.

    Note: Adjustments to the fader do not affect the recording level; they only affect the monitoring level.

Audio General Preferences

The General pane contains the following preferences:

Figure. General Audio preferences.
  • “Display audio engine overload message” checkbox: If unselected, playback will simply stop in an overload situation instead of displaying an alert message.
  • DIM Level slider: This slider lets you set a discrete level for the Dim function. You can set a dim level from 0 dB to –30 dB. The level chosen here is used when the Dim button is activated, either from the Master Volume slider on the Transport bar or from the Master channel strip.
  • Low Latency Mode checkbox and Limit slider: You need to select the Low Latency Mode checkbox in order to activate Low Latency mode and use the Limit slider. The Limit slider lets you determine a maximum amount of allowable delay that can be caused by plug-ins when Low Latency mode is enabled (by clicking the Low Latency Mode button on the Transport bar). In Low Latency mode, plug-ins are bypassed to ensure that all delays (across the entire signal flow of the current track) remain under the Limit slider value. This is useful when you want to play a software instrument with several latency-inducing plug-ins inserted in the channel. For more information, see Working in Low Latency Mode.
  • Crossfade Time slider: Lets you determine a default time value for all crossfade operations in the Arrange area.
  • Crossfade Curve slider: Lets you determine a global curve type for all crossfade operations in the Arrange area.

Audio I/O Assignment Preferences

The I/O Assignments pane offers three further tabs:  Output, Bounce Extensions, and Input.

Output Pane

The Output pane consists of the following preferences:

Figure. Output tab in I/O Assignment preferences.
  • Mirroring checkbox: Becomes available for all chosen output pairs, with the exception of Output 1–2. Deselect to have the output signal routed to the chosen output pair (Output 3–4, for example). Select the checkbox to have the output signal routed to the chosen output pair (Output 3–4, for example), as well as to the physical outputs (Output 1–2).

Bounce Extensions Pane

The Bounce Extensions pane consists of the following preferences:

Figure. Bounce Extensions tab in I/O Assignment preferences.
  • Stereo Left and Right fields: Allow you to set the bounce extension.

Audio Sample Editor Preferences

The Sample Editor pane contains the following preferences:

Figure. Sample Editor preferences.
  • “Warning before processing function by key command” checkbox: Select this option if you want to be warned before carrying out a destructive edit in the Sample Editor using a key command. This gives you the opportunity to cancel the edit operation, before altering the data.
  • “Clear Undo History when quitting” checkbox: Select this option to automatically delete the Undo History for all edited audio files, when you close Logic Express.
  • “Record selection changes in Undo History” checkbox: Select this option if you want to undo and redo changes to selected areas in the Sample Editor.
  • “Record Normalize operations in Undo History” checkbox: Deselect this setting if you don’t want to create undo files when the Normalize function is used.
  • Number of Undo Steps field: Lets you determine the maximum number of undo steps that are retained.
  • “Store undo files in project folder” checkbox: Activate this preference if you want the edited audio files to be stored in a sub-folder of the current project. This is selected by default if the project is saved with its assets.
  • Global Undo File Path field: All files (used by the Undo History) are saved into a global location—a user-defined folder—if the “Store undo files in project folder” option is not selected. Click the Set button, and navigate to the appropriate folder.
  • External Sample Editor field: You can use an external application for sample editing operations, effectively replacing the Logic Express Sample Editor. Click the Set button, and navigate to the application you want to use.

Audio MP3 Preferences

The MP3 pane contains the following preferences:

Figure. MP3 preferences.
  • Use Variable Bit Rate Encoding (VBR) checkbox: Variable Bit Rate (VBR) encoding compresses simpler passages more heavily than harmonically rich passages, generally resulting in better-quality MP3s. Unfortunately, not all MP3 players can accurately decode VBR-encoded MP3s, which is why this option is off by default. If you know that the audience for your MP3 files can decode VBR-encoded MP3s, you can turn this option on.
  • Use Best Encoding checkbox: Like the Quality parameter, if you deselect this option, you will gain encoding speed at the price of audio quality. This should always be left on, unless conversion time is an issue.
  • Filter Frequencies Below 10 Hz checkbox: When this option is selected, frequencies below 10 Hz (which are usually not reproduced by speakers, and are not audible to human ears at any rate) are removed, leaving slightly more data bandwidth for the frequencies that humans can hear, resulting in an improvement in perceived quality. Only deselect this option if you’re experimenting with subsonic test tones, or exporting MP3s for whales.

Audio Reset Preferences

The Reset pane enables you to send reset messages of a specified type to all active instrument channels. This can be useful if you are encountering hung notes, or are finding that controller settings are incorrect when in Cycle mode (or when returning to the beginning of a section or the project start point).

Figure. Reset preferences.
  • “Control 64 off (Sustain)” checkbox: Sends “Control 64 off (Sustain)” reset messages.
  • “Control 1 (Modulation) to zero” checkbox: Sends “Control 1 (Modulation) to zero” reset messages.
  • “Pitch Bend to center position” checkbox: Sends “Pitch Bend to center position” reset messages.