How many harmonics do I need?

Five covers most cases, because a real ground loop buzz puts most of its audible energy in the fundamental and the first few multiples. Raise the count if the buzz still has an edge to it after a pass, and remember that each extra harmonic is one more band where legitimate low-frequency content is being removed.

What does the Q control change?

It sets how narrow each notch is. A high Q removes a very thin slice of the spectrum and leaves almost everything else alone, which is ideal for a stable hum, while a low Q widens the notches so they still catch a hum whose frequency drifts with mains load. Widening always costs some nearby tone.

Is 50 Hz or 60 Hz the right choice?

Match the mains supply where the recording was made: 50 Hz across Europe, most of Asia and much of the rest of the world, 60 Hz in North America and a few other regions. Choosing the wrong one leaves the hum completely untouched while thinning two narrow bands for no reason.

Why is there still a buzz after I remove the hum?

Because notches only remove what sits exactly on the harmonic series. Energy between the harmonics, and noise that changes its character as equipment warms up, is not on the grid and therefore passes through. If the residual is not tonal, the spectral noise reduction tool is the better second step.

Does this fix the cause of the hum?

No. It removes the evidence from a recording that already exists. Ground loops, unbalanced cables and humming power supplies will inject the same buzz into every new take, so treat the tool as a rescue for material you cannot re-record and fix the signal chain before the next session.

Hum Remover

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Hum Remover notches the mains fundamental and as many harmonics as you ask for, which is exactly the comb of tones that ground loops and poor cables inject into a recording. Set the mains frequency for your region, choose the harmonic count and run it.

What is Hum Remover?

Choose 50 Hz or 60 Hz to match your mains, decide how many harmonics to remove and how sharp each notch should be, then process the file. A ground loop or a badly shielded cable injects that comb into every take recorded through it, so this is the repair that matches the damage most exactly. Because every notch sits on an exact multiple of the chosen fundamental, the filter chain is invisible everywhere else in the spectrum, which is what makes it safe to apply to finished music as well as speech.

The real controls:

A mains frequency of 50 Hz for Europe or 60 Hz for the United States, shown as two buttons and defaulting to 50.
A harmonic count from 1 to 10, defaulting to 5, covering the fundamental plus four multiples.
A notch sharpness expressed as Q from 10 to 60 in steps of 5, defaulting to 30.
A report line that lists the fundamental, the harmonic count and every notched frequency in hertz.
A WAV download named after the source with a dehummed suffix.

Every harmonic in the chain is a second order notch built from the standard RBJ biquad formulas and applied in series per channel. The measured behaviour is what you would hope for: at a Q of 30 the fundamental is knocked down below a twentieth of its original amplitude, stacked notches drive 60, 120, 180 and 240 Hz to under two percent residue in steady state, and gain elsewhere in the spectrum stays at unity. Sharpness is the interesting control. A high Q keeps the notches narrow so almost no music is removed alongside the hum, but it also means a hum that drifts in frequency as the grid load changes can slide partly out of the notch. Lower Q widens each one and catches the wander at the cost of a little more tone around every removed band, and the panel notes that mains drift is exactly the case where you need the wider setting.

Its honest limits:

Mains hum that is genuinely broadband has energy between the harmonics too, and notches cannot touch what does not sit on a multiple.
The chain is fixed at the frequencies you chose, so it never tracks a hum that changes pitch during the recording.
Very wide notches on a bass-heavy mix can thin the low end audibly, since the lower harmonics live in the same region as the bass.
It cannot identify the hum for you; if the fundamental is not 50 or 60 Hz the chain is aimed at the wrong place.
Filtering removes energy but does not remove the cause, so the hum will come back on the next take recorded the same way.
The tool writes a new file and offers no live audition, so you judge the settings after the pass rather than during it.

Use it on anything recorded through a dirty mains supply or a laptop charger that was humming into the interface: interviews, voiceovers, guitar DI tracks and transfers where the buzz is a clear low pitch. Set the mains button for your region, leave the harmonic count at five, and widen the notch only if the hum still blinks in and out of the result.

How to use Hum Remover

Load the recording and press the mains button that matches your region, 50 Hz or 60 Hz.
Choose how many harmonics to notch; the default of 5 usually covers the audible part of a ground loop buzz.
Adjust the Q control, keeping it high unless the hum pitch wanders.
Click Remove hum, check the reported frequencies, then download the dehummed WAV.

When to use Hum Remover vs related tools

Hum Remover is the precise instrument for a recognised mains buzz, so reach for it when you can hear a steady low pitch and know the frequency. Background Noise Remover is the broader relative, with more harmonics and a wider notch for a comber backdrop, while Noise Reducer works on broadband noise that has no pitch at all. If the low end is full of rumble rather than a fixed tone, Wind Noise Remover clears it in one highpass instead, and DC Offset Remover deals with the related problem of a waveform that sits off centre.

Privacy & Security

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