Background noise removal is one of the most common steps in preparing a podcast for release. Most recordings tend to have a hum or air-y background noise that is persistent throughout a track, so this step is almost always necessary.
Audio editing programs are very aware of this issue, and they all have tools to tackle the background noise. But sometimes these background noise removal tools don’t remove all the issues that you’re hearing.
In those situations, it’s time to run another noise removal plugin. My personal favorite has been Waves’ NS1 Noise Suppressor tool. Not only does this tool offer a simple slider for removing background noise, but the biggest benefit is that it successfully tackles headphone leakage.
Headphone leakage is when a person’s microphone picks up the voices they’re hearing in their headphones (Side tip: ALWAYS wear headphones while recording). The best way to prevent this problem from occurring is by asking your panelists to keep their headphone volume on the lower side of the spectrum, but in my experience, people have a hard time remembering this rule.
Headphone leakage can be a big problem when you’re editing a podcast that was recorded via Zoom, Skype etc, when your panelists are recording themselves on their own computers, because the leakage will not stay in sync with the original track where those leaked vocals are found. (Note: If you’re recording the Zoom or Skype recording rather than local recordings, these apps will attempt to do their own headphone leakage removal, but that comes at the cost of the panelist with the problematic headphones having their own voice cut out in the event of cross talk).
When headphone leakage can be heard on someone’s track, it’s time to load up NS1 Noise Suppressor. In my experience, this plugin does an excellent job of wiping out most headphone leakage that occurs. This benefit was a big surprise because that type of noise is not a consistent sound. Unlike standard background noise like a ceiling fan or a nearby hum that carries a steady sound, a person’s voice is constantly changing, and yet, the Waves plugin tackles it with ease.
Of course, there are limitations to the plugin’s effectiveness. If a panelist is not wearing headphones (a cardinal sin), their microphone will be picking up other panelists very prominently. A panelist’s headphone volume could also just be extremely loud. In those situations, NS1 will not be able to determine which voices need to be removed.
One word of warning: Like most noise removal tools and techniques, applying too much removal can cause the vocals you actually want to keep to lose their clarity. I try to avoid turning the NS1 Noise Suppressor tool any higher than 30-40%, or else I’ll start noticing big drops in sound quality.
Finally, don’t be afraid to run this plugin on your file(s) more than once. I’ve found that it’s not always perfect after running it once, but running it a second time can take care of remaining issues. Again, you’ll need to be mindful of how much noise removal you’re applying.
Waves has several great plugins for podcasters and other people doing audio work. Last year I wrote about their DeBreath plugin, which helps you reduce the loudness of breaths in an audio track.