If you plan on recording audio from a microphone or an instrument, you'll need a way to get the audio into Logic Pro. Your Mac probably has a built-in line in or microphone. Although these may work in a pinch, professional recordings need higher-quality input devices. The documentation of most professional hardware will show you how to set it up with Logic Pro.
Choose your input and output device
After your hardware is set up and connected to your computer, you must select the hardware in Logic Pro Preferences. To choose your audio input and output devices:
Choose Logic Pro X→Preferences→Audio.
Click the Devices tab.
On the Input Device and Output Device drop-down menus, make your selections.
You can choose separate input and output devices. You may want to record a guitar by using a mobile guitar interface and monitoring through the computer speakers or headphones. In this case, you select the audio interface as the input and select Built-in Output as the output.
Click the Apply Changes button.
Logic Pro will now begin using your selected input and output device for audio.
Set your I/O buffer size and reduce latency
Latency refers to the delay between your audio input and audio output. This delay is unavoidable in software because your sound source must be converted to digital audio and processed before it can be heard. In many cases, latency is negligible and won’t be noticeable. However, latency can become an issue when a track has lots of plug-ins that require significant processing.
It’s a good idea to record most of your tracks before you begin adding lots of plug-ins. The more plug-ins you add, the more processing power required, and the more latency you can introduce into the system. If you record without a lot of plug-ins, latency probably won’t be an issue.
When you record, latency can be a hindrance if you can’t hear what you’re playing exactly when you’re playing it. Fortunately, you can adjust the latency as follows:
Choose Logic Pro X→Preferences→Audio.
Click the Devices tab.
On the I/O Buffer Size drop-down menu, make your selections.
Note that a smaller buffer size will reduce latency.
A smaller buffer size requires more processing power. If you set the buffer size too low, you can introduce clicks and pops in your audio. Experiment with the buffer size until you find a setting that minimizes latency but doesn’t introduce unwanted audio artifacts.
Click the Apply Changes button.
Logic Pro will begin using your selected I/O buffer size.
Monitor signals through your hardware or software
Some audio interfaces have built-in monitoring capabilities. This means you can listen to the source material you're recording through your hardware instead of through the Logic Pro X software. Monitoring through your hardware is useful if the software introduces too much latency.
By default, Logic Pro monitors audio through the software. To turn software monitoring off, follow these steps:
Choose Logic Pro X→Preferences→Audio.
Click the Devices tab.
Deselect the Software Monitoring check box.
If no hardware is connected, the check box will appear dimmed and will be unavailable.
The Software Monitoring check box is available only if Show Advanced Tools is selected in the Advanced pane of Logic Pro X Preferences.
Click the Apply Changes button.
Audio will no longer be monitored through Logic Pro.