For a steady electrical-sounding hum, inspect a quiet interval's spectrum before applying broad noise reduction. A narrow correction can be appropriate when the unwanted sound is concentrated around stable frequencies. Do not select a frequency solely from the country or call every low sound mains hum.
Gather a real quiet reference
Use a pause recorded with the same microphone and equipment state as the speech. Listen and view the spectrum. A stable frequency line and its possible harmonics are different from wide-band traffic, fan airflow or room reverberation. Speech itself contains changing low-frequency energy, so an active word is a poor sole noise sample.
Audacity's spectral-selection guidance describes selecting frequency regions and applying targeted spectral edits, including notch treatment. It supports a narrow-band workflow, not automatic identification of the electrical cause or perfect removal of every harmonic.
Investigate the recording path first
If a new recording is possible, compare the setup with unnecessary equipment disconnected or another suitable power arrangement, following the equipment's own instructions. Avoid unsafe electrical modifications. A clearer recording may be preferable to heavy repair of a finished take.
For an existing take, keep the raw audio and create a short test that includes both a pause and a low-pitched phrase. Work on the measured unwanted frequency region. Change one correction at a time and compare at similar listening level.
A hypothetical narration repair
Suppose a narration contains a steady narrow tone audible in pauses. The spectrum suggests a consistent line with weaker related lines above it. The editor tests a restrained notch on the strongest unwanted line and listens to a phrase with a low voice.
If the hum becomes less intrusive but the voice loses body, reduce the treatment or reconsider the usable source. Removing every visible peak is not the goal; some peaks belong to the speaker. This is a hypothetical process, not a measured electrical diagnosis or a tested frequency prescription.
Review the whole recording state
Equipment noise can change after a cable move or device switch. A correction that works in the opening may fail later. Mark intervals with different background behavior and review them separately instead of forcing the entire take through one setting.
Accept when the identified hum is less distracting and required voice detail remains intact. Reject a thinner voice, audible ringing or a broad cut used without frequency evidence. Check the processed take under the final music and again alone. Save the quiet reference, measured frequency region and approved settings privately with the project. This is an external audio-restoration workflow; an Imagild narration request does not establish a mains-hum detector or guarantee recovery from damaged recording conditions.
Sources
Prepared by Imagild Editorial with AI assistance and reviewed against the linked sources on October 13, 2026. Examples are hypothetical; external procedures do not establish Imagild features or guarantee results.