How to remove low-frequency background hum without affecting voice in Audacity?

[john65]

Hi all,

I’m working with some voice recordings where there’s a noticeable low-frequency hum in the background, but most online tutorials for noise removal also end up dulling the voice quality if I apply them aggressively. I’m hoping to isolate and reduce just the hum without losing clarity in the spoken parts.

Here’s my setup:
Audacity 3.2.5 on Windows 10
Source recordings captured on a USB mic

Things I’ve tried so far:
• Using Noise Reduction with a noise profile taken from a silent section reduces the hum a bit, but also affects voice clarity.
• Applying High Pass Filter at various cutoffs too low doesn’t fix it, too high thins the voice.
• Using Notch Filter for known hum frequency helpful but not enough on its own.

For context, I manage audio for projects like [link deleted] where spoken instructions and narration need to sound clear even after cleanup, so getting a solid balance is important.

Is there a workflow or combination of effects in Audacity that’s proven effective for reducing low-frequency hum while preserving vocal fidelity? Are there specific filter settings or processing order that others here have found that works well?

Thanks for any tips!

[Trebor]

If *it’s mains hum, there’s a Audacity specific plug-in …

https://plugins.audacityteam.org/nyquist-plugins/effect-plugins/filters-and-eq#hum-remover

[* other sources of constant noise are possible ].

[sonicy]

It’s a bit unfortunate that you didn’t include a sample clip. Otherwise, it would’ve been a great chance for me to test a speech separation model I recently trained that can extract clean dialogue from noisy recordings. If you’re open to sharing a short sample, I’d be happy to give it a try.