Background Noise / Webcam Audio Hum

If you have a laptop with a built-in webcam and you record video you (and your viewers) may notice a ton of background noise or annoying hum when you play the video back. Since the webcam often grabs audio from the built-in microphone, what you’re hearing is the vibration from noisy components (fans, hard drives, etc) inside your computer going about the chassis and up through the microphone. It doesn’t help that recording video is an intensive process for most standard issue laptops. When recording, do you notice if the fans are spinning wildly? Here are some tips to correct the audio:

  • Fix it in Post – While this is an easy task for short videos, a video longer than 10 minutes may take hours to render, depending on your hardware specs. It’s like a double edged sword. If you’ve got a beefier laptop, chances are you’ve got better hardware. Better hardware needs better cooling, better cooling means your fans spin faster ANNND we’re back at square one =( Here’s a link to Audacity’s Wiki. Basically you take a sample of the beginning or end of your video where you’re not talking, since you’re silent, but the hum/buzz is still there, it’ll know what frequency to remove. Play around with short clips before you commit to a full render (or fix the audio separately and re-render with the new track)!
  • Cool your laptop – If you notice your laptop fans start to spin when you record, perhaps you need to be cooling it down more. Elevate the laptop so the exhaust fans (usually the bottom) aren’t blocked. They may be in a push-pull configuration, meaning the fans are pushing air out while sucking air in through another opening. Whatever the case may be, make sure you’re not blocking the fan that provides cool air, and make sure it’s easy for the laptop to vent the hot air.
  • Ground your power supply – Some laptops come with the option to use a 2 prong plug or a 3 prong plug when plugging in to a wall outlet. When recording opt to plug in with the 3 prong plug. This helps in several ways:
    • Some power profiles give precedence to different tasks when unplugged, give your laptop the juice boost it may be looking for.
    • It fully grounds your computer. Most humming/buzzing in the world of audio equipment is because of a ground loop.
  • Buy an external microphone – Even a cheaper microphone is better than your webcam/on-board mic. I wish I could provide suggestions, but I’m sure you can find a good one on amazon. Audio-Technica has a condenser microphone for sale that ranks #17 on Amazon for around $25. Check out the video review to hear the difference between the onboard microphone of his camcorder and the ATR 3350. It is a mono mic so you’ll have to dupe the L/R tracks, but in Audacity that’s pretty easy.
  • Buy a video camera (or use your phone’s video camera) – Since you wouldn’t be recording on your laptop, there should be no issues with audio unless you’ve got a really noisy background. Most camera phones these days will let you record video. The microphones are much better too.

Hopefully this quick post has helped you isolate and fix noise issues in webcam recorded videos. While I’ve included free and more expensive solutions, getting an external mic would probably be the most cost effective solution (not to mention the time you’ll save in post).

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