Drift Correction in Audio MIDI Setup: What It Does and When to Enable It
Learn what drift correction does in Audio MIDI Setup on macOS, when to enable it, and what to check before changing this setting for your audio devices.
Overview
Drift correction, sometimes called resampling in older descriptions, makes one audio device follow the clock of another device. In Audio MIDI Setup on macOS, the practical use is usually to keep two or more audio interfaces or sound sources aligned over time, so that audio does not fall out of sync.
The most common condition for enabling this feature is when you are using separate digital audio devices together, rather than a single microphone plugged directly into one interface. If you only use one microphone, webcam, or external audio interface on its own, drift correction is generally not needed.
What Drift Correction Means
Digital audio devices have internal clocks that determine how many samples are produced or consumed per second. Even when two devices are both set to 48 kHz, small differences between their clocks can make one device run very slightly faster or slower. Over a long recording or meeting, this difference can grow into a noticeable timing drift.
Drift correction in Audio MIDI Setup is a way to tell macOS to treat one device as the clock reference and adjust another device to follow it. The adjustment is applied to the device that does not serve as the clock master. This is a reversible software setting in macOS; it does not alter the device hardware.
When to Enable Drift Correction
Consider enabling drift correction only when two or more devices are being used as separate audio inputs or outputs at the same time outside a single clock-control arrangement. This can include two USB interfaces used together in an aggregate device, or a digital input and output connection where the devices do not share a hardware clock.
If you use a webcam with a built-in microphone and a separate USB microphone at the same time for recording, that is not usually a drift correction scenario by itself. Drift affects clock alignment between audio devices; selection and permission issues in apps are separate problems.
Steps to Enable Drift Correction in Audio MIDI Setup
To check or adjust this setting, open Audio MIDI Setup, select the device in the sidebar, and look for an option labeled Drift Correction or Resampling. The exact label can depend on the macOS version.
- Open Audio MIDI Setup from the Utilities folder or through Spotlight.
- Select the device you want to adjust in the audio window sidebar.
- Find the Drift Correction checkbox for that device.
- Enable it if this device should follow the clock of another device in the setup.
- Leave it unchecked when the device is the clock master or the only device in use.
- Test the original audio synchronization problem after changing the setting.
How to Know the Change Worked
Retest the condition that originally showed the problem. If the issue was gradual loss of sync during long recordings or sessions, check whether the timing gap remains stable instead of growing. If the audio was distorted or stuttering after enabling drift correction, revert the checkbox and verify the symptom.
Drift correction is a reversible change, so the first remedy is to toggle it for the intended secondary device and retest. If the original problem remains or the audio becomes unstable, stop changing advanced settings in Audio MIDI Setup and test one device at a time.
When to Stay Away From This Setting
A single microphone or webcam microphone should be selected in the app you are using, not fixed with an Audio MIDI Setup drift correction option. If a microphone is not appearing in an app, the cause is likely device detection, privacy permission, or input selection, not clock drift.
The information here applies to Apple’s Audio MIDI Setup utility on macOS. Different interfaces may expose their own clock or sync controls in their proprietary software. Documented behavior can vary by macOS version and device driver, so if the checkbox for a device is unavailable, treat that as a gap in the available options rather than a sign that the feature is broken.
Summary
Drift correction in Audio MIDI Setup makes a connected digital audio device follow another device’s clock to prevent gradual sync loss. It matters only when you are deliberately running multiple audio devices together without a shared hardware clock. For a single mic or webcam input, this setting is usually irrelevant, and input permission or selection issues should be checked first.