How to Eliminate 50Hz/60Hz Electrical Hum from Audio (Without Ruining the Voice)

First, Confirm It’s 50Hz/60Hz Hum (Not Rumble or Hiss)

Electrical hum has a signature: a steady low tone and a stack of harmonics. 60 Hz hum from North America usually shows up at 60, 120, 180, 240 Hz, and so on. 50 Hz hum from Europe, much of Asia, Africa, and Australia appears at 50, 100, 150, 200 Hz. If you remove only the fundamental, the buzz often remains because the harmonics are doing the audible damage.

Open your recording in an editor and look at a quiet gap between words. In Audacity, use Analyze > Plot Spectrum. In Adobe Audition, use Window > Frequency Analysis. In DaVinci Resolve, open Fairlight and view the spectrogram. You want thin horizontal lines at 50 or 60 and its multiples. If the energy is a broad low rumble, that is HVAC or handling noise, not electrical hum. If it crackles, it is interference, not steady hum.

A quick test: unplug your laptop charger or move the mic cable away from a power strip. If the hum changes or disappears, you have found the source.

Fix the Source First (It Beats Any Plugin)

No cleanup tool can fully remove loud, clipped hum without side effects. Fixing the recording setup gives a better result with less voice damage.

• Run laptops on battery while recording. Cheap chargers and USB power are common hum sources.
• Use balanced XLR cables and a proper audio interface. Unbalanced 3.5mm cables pick up more electrical noise.
• Route audio cables away from power bricks, extension cords, dimmer switches, and fluorescent lights.
• Use a ground loop isolator or DI box for USB/computer-to-mixer hum. Do not defeat the safety ground on a mains plug.
• For phone recordings, enable airplane mode, avoid charging, and use an external lav or USB mic if possible.
• In Zoom or OBS, disable mic boost and use a headset or interface. Built-in laptop mics often combine voice and electrical noise.

Tradeoff: hardware fixes take time before the session, but they preserve the voice. Software cleanup should be the second line of defense.

Manual Cleanup: High-Pass, Notch, and Harmonics

If you already have the file, clean it in this order: high-pass, notch fundamental, notch harmonics, then AI voice isolation if needed.

1. High-pass filter

For 60 Hz hum, set a high-pass filter at 70-80 Hz with a 12 dB/octave slope. For 50 Hz hum, try 60-70 Hz. This removes the fundamental but not 120/180 or 100/150. It is a gentle first move, not a full fix. Tradeoff: a 100 Hz high-pass on a deep male voice can make it sound thin, so start lower and listen.

2. Notch the fundamental

Use a narrow notch exactly at 50 or 60 Hz. In Audacity, choose Effect > Notch Filter. Start with Q=10, then move to Q=20 or Q=30 if the voice sounds hollow. Reduce by -18 to -30 dB. In Reaper, use ReaEQ with Q=20 and gain around -20 dB. In Adobe Audition, use Effects > Noise Reduction/Restoration > DeHum and set the fundamental to 50 or 60 Hz.

3. Notch the harmonics

Add narrow notches at the first two to four harmonics. For 60 Hz hum: 120, 180, 240, 300 Hz. For 50 Hz hum: 100, 150, 200, 250 Hz. Use the same narrow Q and depth, but reduce depth if the voice starts to sound phasey. In iZotope RX, De-hum can do this automatically with 4-8 harmonics. In DaVinci Resolve Fairlight, use the hum removal or EQ bands.

Tradeoff: stacking many notches can make speech sound underwater, hollow, or lispy. Always A/B bypass. Do not notch above 300-400 Hz unless the spectrogram clearly shows hum harmonics there.

When AI Voice Isolation Is the Better Tool

Manual notching works well for steady electrical hum, but real recordings often have hum plus fan noise, keyboard clicks, room tone, and traffic. AI voice isolation for specific background noises separates speech from steady noise instead of carving out frequencies. That can remove 50/60 Hz hum and its harmonics while keeping consonants and plosives intact. If you would rather not hand-notch every harmonic, a free online option like ClearVoice can handle it as a voice-isolation step. Upload the clip, choose voice isolation or background noise removal, then compare before and after.

For a quick pass, use a free tool like ClearVoiceHQ (clearvoicehq.com), upload the file, and select the voice isolation mode. It is useful for podcasts, voice memos, Zoom calls, phone recordings, and gaming clips. Tradeoff: aggressive AI can dull room reverb, remove breaths, or add metallic artifacts. Use a lower strength setting if available, or process only the noisy sections.

Step-by-Step Workflow for a Real Recording

1. Duplicate the track so the original stays untouched.
2. Find a silent gap and run a spectrum analysis. Note whether the hum is 50 or 60 Hz and which harmonics are visible.
3. Apply a high-pass filter at 60-70 Hz for 50 Hz hum, or 70-80 Hz for 60 Hz hum. Use 12 dB/octave first.
4. Notch the fundamental and first 2-4 harmonics with a narrow Q. Check on headphones.
5. If hum is still audible, run AI voice isolation. ClearVoice or a similar tool can remove the remaining steady noise.
6. Check the result on phone speaker, laptop speaker, and headphones. If the voice sounds thin, reduce notch depth or high-pass slope.
7. Export as 24-bit WAV or high-quality AAC. Avoid stacking multiple lossy encodes.

For Zoom, OBS, or Discord clips, you can enable built-in noise suppression, but it often pumps and removes music. For critical audio, record locally and clean afterward.

Common Mistakes and Tradeoffs

• Using a 50 Hz notch on 60 Hz hum. Check your region and the spectrum, not the label on the file.
• Notching too wide. A Q of 5 removes too much voice; Q of 20-30 is usually safer.
• Removing only the fundamental. The 120/180 or 100/150 harmonics are often more audible.
• Overusing high-pass. A 100 Hz high-pass on a deep voice can make it sound like a phone call.
• Expecting AI to fix clipped, distorted hum. If the hum overloaded the input, re-record or fix the hardware.

Bottom Line

To eliminate 50Hz/60Hz electrical hum from audio, fix the source when you can, then use a high-pass filter, narrow notches at the fundamental and harmonics, and AI voice isolation for complex recordings. ClearVoice is a free online option if you want the hum removed without building a notch chain. Always A/B and check on multiple speakers. The best result is hum-free but still sounds like the person, not like a plugin.