Devices settings in Logic Pro for Mac

Logic Pro for Mac 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, you may want to optimize the settings for your individual hardware setup, particularly if you use several audio interfaces or a multiple input/output device.

The Audio Devices Settings pane contains the following settings:

• Core Audio Enabled checkbox: The Core Audio driver in Logic Pro has to be turned on to record and play back audio in your project. The following happens if the checkbox is unselected:

  • You won’t hear any audio on the audio inputs or during playback.

  • All audio effect and software instrument plug-ins loaded on channel strips are turned off, as indicated by an orange triangle on an active plug-in slot.

  • You can’t open any plug-in windows.

  • Plug-in menus don’t list any audio effect and software instrument plug-ins.

  • Aux channel strips not assigned to a track are hidden from the Mixer.

  • You can still use your project to record and play back MIDI.

• Output Device pop-up menu: Use to choose between any installed Core Audio device, including the internal sound hardware. This also includes aggregate audio devices, consisting of several audio interfaces. See the Audio MIDI Setup Help for information on aggregate devices.

  Tip: To play your project through a HomePod speaker or any AirPlay-supported device, open the Audio Devices window in the Audio MIDI Setup utility, click the button in the lower left corner, and choose a device from the Connect AirPlay Device submenu. The AirPlay device is added in the sidebar and also appears in the Logic Pro Output Device pop-up menu.

• Input Device pop-up menu: Use to choose between any installed Core Audio device, including the internal sound hardware. When you select an output device that also provides inputs, the Input Device pop-up menu changes accordingly. If choosing a different input device, you’ll be advised to use a common Word Clock for both audio devices in order to ensure the best sound quality.

  Note: The selected audio devices are stored with the project. If the selected device is not available on a computer when you open the project, a dialog provides the option to select the previously used audio device, or choose a different one from the Audio settings.

• Allow Access button: Click to open System Settings > Privacy & Security > Microphone. The Logic Pro switch determines whether Logic Pro can receive audio signals from the device selected in the Input Device pop-up menu. You have to restart Logic Pro when changing the status.

  The button is only displayed if the Logic Pro switch is set to off in the System Settings.

• I/O Buffer Size pop-up menu: Determines the size of a special memory location (referred to as an I/O buffer) that the audio stream passes through when transmitted between your computer’s processor and your audio device. The smaller the buffer size, the less latency you encounter when you monitor while recording using a microphone or a software instrument.

  Some points to note:

  • As the value is reduced, a higher strain is placed on your computer’s processor or processors.

  • There may be a point where the selected I/O buffer size is too small for your computer, and begins to affect playback. This usually takes the form of clicks, pops, and crackles in your audio.

  • You should aim for the lowest possible I/O buffer size value that doesn’t introduce clicks, pops, and crackles in your audio.

  Tip: If you often switch the I/O buffer size between a higher value (for mixing) and a lower value (for recording), you can display the I/O buffer size in the custom control bar display by selecting the Sample Rate / Buffer Size checkbox in the “Customize Control Bar and Display” dialog. The display then shows the current I/O buffer size, which you can click to choose a different setting from the pop-up menu. See Customize the control bar.

• Resulting Latency (Roundtrip/Output) display: Displays the resulting roundtrip and output latency for the I/O buffer size.

• Apply Changes button: Reloads the audio driver with any adjustments made to settings in this window.

When Enable Complete Features is selected in Advanced settings, the following are available:

• Recording Delay slider: Delays the recording of audio by a certain fixed value, helping you to compensate for any delays that are caused by the audio driver.

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

• Processing Threads pop-up menu: Choose the maximum number of processing threads used, or have the number of threads set automatically. Automatic is the default setting, and is recommended except when you use other CPU-intensive applications simultaneously with Logic Pro.

• Process Buffer Range pop-up menu: Determines the size of the buffer used to compute mixes and effects. You can choose between Small, Medium, and Large buffer sizes.

• Multithreading pop-up menu: Determines whether multithreading is set for playback tracks only, or for playback and live tracks.

• Summing pop-up menu: Determines whether the Logic Pro audio engine uses double precision (64-bit) or standard precision (32-bit) buffers when summing audio. This setting applies to the Mixer, where the audio signals of all channel strips are summed together to the output channel strip. Higher precision results in greater accuracy during data processing and, therefore, delivers better-sounding results