Audio processed by some effect and instrument plug-ins may incur small timing delays, known as latency. A signal may incur input latency, output latency, or both. For example, playing a software instrument in Logic Pro only incurs an output latency because its audio is generated by the application. However, an audio recording that is being monitored in real time has both an input and an output latency because the signal must be input into Logic Pro before it can be processed. Input latency (if any) and output latency are summed, resulting in an overall monitoring latency. Each further process—such as the use of insert effects, for example—may also add an amount of latency, which is added to the overall monitoring latency.
In Logic Pro, you can compensate for internal latencies introduced by plug-ins, ensuring that all track and channel strip output is perfectly synchronized.
You can also turn plug-in latency compensation on or off, for audio and software instrument tracks or for all channels (audio, instrument, aux, output, and ReWire). When this setting is turned on, Logic Pro compensates for latency introduced by plug-ins, ensuring that audio routed through them is synchronized with all other audio. This is achieved by calculating the amount of latency caused by plug-ins, and then delaying audio streams by an appropriate amount—or shifting instrument and audio tracks forward in time.
Do one of the following:
Click the Low Latency Mode button in the control bar.
Select the Low Latency Mode checkbox in General Audio preferences.
Recorded audio is routed around any latency causing plug-ins in the signal path to ensure that the maximum delay that can occur across the entire signal flow (of the current track’s signal path) remains under the Limit slider value in General Audio preferences.
The sound may change when you turn on Low Latency mode. Depending on the plug-ins in use, the change in sound can be anything from subtle to dramatic. If plug-ins being used do not exceed the total latency limit, there is no audible difference.
Choose an option from the Compensation pop-up menu in General Audio preferences.
If latency-inducing plug-ins are inserted into audio or instrument channel strips, Logic Pro automatically shifts these tracks forward in time. The advantage of this method is that other channel strips (that do not contain latency-inducing plug-ins) do not need to be delayed.
If latency-inducing plug-ins are inserted into aux or output channel strips (or ReWire channels, if used), Logic Pro delays all other audio streams by an appropriate amount.