Reducing Monitoring Latency

For more information, see the following topics:

Low Latency Monitoring and Bounce To Disk

There will inevitably be some audio delay, or latency, in the monitoring signal (even if only a few samples) due to the process of converting an analog signal to a digital signal (input) and back again (output). There may be additional latency due to mixer configurations and processing.

Avid HDX and Pro Tools|HD systems have additional latency when using host-based plug-ins (RTAS and AAX) because these plug-ins also use your computer’s host processor.

Host-based Pro Tools systems use the host processor in your computer for all audio processing, playback, and recording, so there is always a small amount of latency in the system. For example, there may be some audible delay between the incoming signal and outgoing signal when monitoring recording through Pro Tools.

With Pro Tools, latency occurs as follows:

All Pro Tools systems can have RTAS MIDI-to-audio latency (such as when playing an RTAS virtual instrument live and monitoring the instrument’s output).

Pro Tools systems have input-to-output monitoring latency on any record-armed tracks or Auxiliary Inputs with live inputs.

Avid HDX and Pro Tools|HD systems have monitoring latency on tracks that have one or more host-based plug-ins.

The latency amount is related to the H/W Buffer Size setting—the larger the buffer size the greater the latency. You can reduce the amount of monitoring latency by reducing the H/W Buffer Size setting. However, even at the smallest buffer size, there is still some latency.

In addition, reducing the buffer size limits the number of simultaneous audio tracks you can record without encountering performance errors.

While there may be times when you want a larger buffer size, such as when you have higher track counts with more plug-ins, you will generally want the smallest possible buffer size when latency is present during recording and monitoring.

If you are monitoring the recording source with an external mixer before it is routed to Pro Tools, you will not hear any latency.

To set the Hardware Buffer Size:

1 Choose Setup > Playback Engine.

2 Choose the number of samples from the H/W Buffer Size pop-up menu.

3 Click OK.

For more information on the H/W Buffer Size setting, see Hardware Buffer Size.

Computers with slower CPUs may not be able to use a H/W Buffer Size setting lower than 512 samples buffer size without encountering performance errors.