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Mic delay is most noticeable when using a microphone to supplement unfinished parts of the official recording session or replace unsatisfactory sections, or overdubbing onto an existing audio track. If you use Audacity to process your audio editing tasks and find that your microphone input is not synchronized with the background audio track, you can use the program's delay adjustment tool to fix the mic delay issue. Here's what you need to do:
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Fixing Mic Delay in Audacity
Step 1: Connect one end of a 1/8 inch audio cable to the Line In port on your computer's Sound Card and the other end to the Headphone or Audio In port of the Sound Card. Alternatively, you can plug a USB microphone into the USB port on your computer and position the microphone in front of your computer's speakers.
Step 2: Open Audacity and click on Edit > Preferences. Then select the Recording tab in the Preferences menu.
Step 3: Check the option Play other tracks while recording (overdub) and uncheck the box Software playthrough of input. Enter 0 in the Latency Correction field and click OK to close the Preferences menu.
Step 4: Click on Generate > Click Track. Enter 2 in the Number of measures field and choose the Tick option from the Click Sound menu. Click OK to create the click track.
Step 5: Press the Record button to record the sound of the click track onto a new audio track (dub track). The new track will appear below the click track and will stop recording at the end of the click track. So, the top one is the original click track and the bottom one is the repeated recording.
Step 6: Click on the Zoom Tool in Audacity's toolbar and one of the two audio tracks to zoom in on both. Scroll the track window scroll bar to the left to identify the position of the first click on the waveform of the click track. You'll need to compare the space or latency between the first click on the waveform of the top track and the first click on the waveform of the bottom track.
Step 7: Click the Selection Tool. Move the cursor to the start of the click in the bottom track. Drag the cursor from the beginning of the click in the bottom track to the beginning of the first click in the top track.
Step 8: Uncheck Snap To at the bottom of the Audacity window. Click the Length button and click the arrow button in the menu box of the Length field. Choose the hh:mm:ss + milliseconds option from the context menu that appears. The Length field will display the latency in your selection in milliseconds - record this number.
Step 9: Click Edit > Preferences and select the Recording tab in the Preferences menu.
Step 10: Enter the latency value into the Latency Correction field, add a minus sign - to indicate that the value is negative, and click OK to save your latency adjustment.
Follow the instructions in the article exactly and you will fix the mic delay issue in Audacity. However, note that the result is not 100% perfect. There is still a slight difference, but it will be hard for you to notice when listening. Additionally, check out How to separate vocals from a song using Audacity here for more reference.
