How to Calibrate Latency in Audacity

Hardware latency causes newly recorded audio tracks to fall out of sync with pre-existing tracks during multi-track recording. This guide explains how to eliminate this delay by setting up Audacity's recording options, measuring your hardware's exact audio lag using a loopback test, and applying that value to Audacity's latency compensation settings for perfectly synchronized audio.

Step 1: Enable Overdubbing

Before measuring latency, Audacity must be configured to play existing tracks while recording new ones.

  1. Open Audacity.
  2. Go to the top menu and select Transport > Transport Options.
  3. Ensure that Overdub (on/off) is checked.

Step 2: Set Up a Click Track

You need an audio reference with sharp, precise peaks to measure the timing difference accurately.

  1. Go to Generate > Rhythm Track (or Click Track in older versions).
  2. Set the number of bars to 2 or 3 and click OK.
  3. Change your project selection format to milliseconds by clicking the menu on the Selection Toolbar at the bottom of the window and selecting Start and Length of Selection, then choosing hh:mm:ss + milliseconds.

Step 3: Perform the Loopback Test

The loopback test records the output audio back into the input hardware to capture the time delay.

  1. If you are using a microphone, take off your headphones, turn up the volume, and place the headphones directly against the microphone so the mic can clearly pick up the click sound. If you are using an audio interface, you can connect an output channel back into an input channel using a patch cable.
  2. Press the Record button (or press R).
  3. Let the click track play completely and record onto a new track.
  4. Press Stop (or the spacebar).

Step 4: Measure the Delay

  1. Zoom in closely on the first click of both tracks using the Zoom Tool or Ctrl + 1 (Cmd + 1 on macOS).
  2. Locate the sharp initial peak of the click on Track 1 (the original generated track).
  3. Locate the corresponding peak on Track 2 (the recorded track), which will appear slightly to the right of the original track.
  4. Click and drag the cursor from the peak of Track 1 to the peak of Track 2.
  5. Check the Length field in the Selection Toolbar at the bottom of the screen. This number represents the latency in milliseconds (for example, 45 ms).

Step 5: Adjust Latency Compensation

  1. Open preferences by navigating to Edit > Preferences (or Audacity > Preferences on macOS).
  2. Select Audio Settings (or Devices in older versions) from the left sidebar.
  3. Locate the Latency section.
  4. Find the Latency compensation field. This field normally contains a default negative number (such as -130 ms).
  5. Add your measured delay to the existing number. Because compensation requires shifting the track further back, subtract the measured milliseconds:
    • Formula: Current Value - Measured Latency = New Latency Compensation Value
    • Example: If the current setting is -130 ms and your measured delay was 45 ms, enter -175 ms.
  6. Click OK to save the changes.

Step 6: Verify the Calibration

  1. Delete the recorded test track by clicking the X in the top-left corner of its track control panel.
  2. Press Record again to re-record the click track using the same loopback setup.
  3. Zoom in on the peaks. The sharp transients of both tracks should now align directly on top of each other. If a slight discrepancy remains, fine-tune the latency compensation number by a few milliseconds until alignment is exact.