How to reduce latency in MainStage
Use advanced settings in MainStage to minimise the amount of latency (delay) you experience when playing software instruments.
When playing a software instrument in MainStage, you may experience a slight delay between when you play a note and when you hear the sound from your speakers or headphones. This delay is called latency and is caused by buffering within your Mac.
Here’s how to quickly optimise your latency settings in MainStage:
In MainStage, load the patch or concert in which you’re experiencing the most latency.
Choose MainStage > Preferences, choose Audio, then click Advanced Settings.
Click the I/O Buffer Size pop-up menu, then choose the lowest number available.
Play some notes. If you hear unwanted audio artefacts, such as dropouts, pops or glitches, choose the next highest setting until you can no longer hear any audio artefacts.
If the lowest I/O Buffer Size setting you can use without audio artefacts has too much latency for you to perform comfortably, choose the next lowest I/O buffer size, then turn on the I/O Safety Buffer.
Once you have determined the best buffer settings, try lowering the Driver Latency slider to further reduce the overall latency of your system.
Advanced audio settings in MainStage
This section provides more details on the advanced preference settings in MainStage that affect latency.
I/O Buffer Size
For audio channel strips, the I/O Buffer Size sets both the input and an output buffer size. For software instrument channel strips, the I/O buffer size only sets the output buffer size – there’s no audio input for these channel strips. The buffer size ranges from 16 to 1024 samples.
When you change the I/O Buffer Size setting, you can see how it affects the total amount of input and output latency, which is shown as Roundtrip in milliseconds under the Latency heading. The output latency is also shown in brackets. With software instruments, the output latency is the important number.
Lower I/O Buffer Sizes result in less latency, but may induce audio artefacts, especially if you use a lot of plug-ins and channel strips simultaneously. If you want less latency but are experiencing audio artefacts, you can reduce the number of plug-ins and channel strips you’re using simultaneously.
I/O Safety Buffer
When you turn on the I/O Safety Buffer, MainStage will add an additional output buffer to protect against overloads due to unexpected CPU spikes. Its size is equal to the I/O Buffer Size setting, but it only affects the output buffer.
For example, if you find there’s too much latency with an I/O Buffer Size of 256 samples, but you’re hearing unwanted audio artefacts with an I/O Buffer Size of 128 samples, set the I/O Buffer Size to 128 and turn on the I/O Safety Buffer. This will yield more latency than 128 samples without the Safety Buffer, but less than 256 samples without it.
Driver Latency slider
The Driver Latency slider affects the latency of the Core Audio driver, which then passes the signal to your audio output, such as the headphone output on your Mac or an external audio interface. By default the slider is set to the maximum possible value, equal to the current I/O Buffer Size. When you move the slider to the left to reduce driver latency, the latency of the overall roundtrip latency is also reduced.
As with the I/O buffer size, lower Driver Latency settings can lead to unwanted audio artefacts. The minimum setting possible for a particular system is primarily determined by the audio driver. The Driver Latency setting has no effect on the number of plug-ins or channel strips you can run.