Here’s a good simple explanation. Although it relates to Logic, the concept is the same in all DAWs.
Adjust the I/O buffer size
The I/O buffers temporarily store some of the incoming and outgoing audio data to protect against audible dropouts, clicks, or pops. You can change the I/O buffer size at any time to minimize latency.
In Logic Pro, smaller I/O buffer sizes reduce input monitoring latency. However, smaller buffer sizes require more processing power, which can cause system overload alerts. Larger I/O buffer sizes require less processing power, but increase latency.
When recording, set the I/O buffer to the lowest setting. If you encounter system overload alerts, increase the I/O buffer size to the next setting. Projects with many tracks or a lot of software instruments require higher I/O buffer sizes, depending on the amount or RAM and the speed of the processor in your Mac.
To change the I/O buffer size:
- Choose Logic Pro X > Preferences > Audio.
- Click Devices.
- Choose the buffer size from the I/O Buffer Size pop-up menu. If you're using a USB interface, set the I/O buffer size to no less than 128 samples. For Thunderbolt interfaces, you can set the I/O buffer size to the lowest setting.
Logic Pro shows the resulting latency under the I/O Buffer Size menu. Roundtrip latency is the total amount of input monitoring latency you'll experience from audio input to audio output.
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Turn Low Latency Mode on to manage plug-in latency
Certain plug-ins can contribute to input monitoring latency, particularly dynamics plug-ins with look-ahead functions. If you're using these kinds of plug-ins in a project, you can minimize the latency they produce while recording using Low Latency Mode.
Low Latency Mode bypasses plug-ins as needed, so the amount of latency doesn't exceed the Limit setting in the Plug-in Latency section of the General Audio preferences of Logic Pro. Low latency mode is especially useful when you want to record a software instrument in a project that includes latency-inducing plug-ins.
To turn Low Latency Mode on, choose Record > Low Latency Mode.