Removing Grounding Noise From A Sample

i wanted to record some scratches to use as samples and i got a grounding buzz all over. since this buzz is relatively constant, i imagine there could be a way to edit the sample by substracting the buzz from the original, like (scratch+buzz)-buzz=scratch
is it possible??

thanks in advance,

you can do this in audacity.

effect>noise removal. :)

I’d just use a parametric EQ, set to the frequencies that need to be removed.

high pass filter or whatever the opposite of band-pass filter is called.

if you use Audacity for this, make sure you put the slider down to minimum effect as it will generally be enough. you will probably find that using this effect can cause a metallic sound in your sample, because it removes ‘too much’. at least this is the effect on my own voice when i use Audacity.

This would be my first port of call.

If it’s an earth hum it should be 50/60 Hz depending on what the supply is where you live. Likely to have at lease some first harmonic at double that as well.

Some programs have a hum/noise removal tool that you have to select a “quiet” section of the recording and they will calculate the frequency content of the noise and then automatically remove it. The other type of noise removal tools I generally don’t find work to well.

As it’s a scratch sound it’s probably mostly mid-range so you may get away with using a high pass filter to remove a lot of the lower end as well.

Ok I just saw this thread! I recommend adobe audition over audacity a million times over for noise removal. Both programs work on the same principle where you basically have to find a spot where it is just the unwanted noise and then highlight it, capture the noise print and then subtract the noise, but adobe does this way better. When you use audacity it really messes with the other good audio and degrades the quality but with adobe I found I could really cut noise out of quiet samples like a soft violin taken from an old fuzzy sounding claymation movie and it cleaned it up beautifully.

I’d much rather have a tip or a trick posted on here about how to ground your equipment so you don’t get ground hum with piezomics + microphones

I really wouldn’t spend money on Audition just to remove ground hum. As others have suggested using an EQ would work well.

Agreed, you can polish a turd all you want but it will still be a turd, not an insult just adjusting an old audio saying for this situation. Every device in your signal chain needs to be working correctly. In the end it will sound much better if the hum is prevented rather than removed later with software.

[quote=“Rouwe, post:9, topic:33669”]
I really wouldn’t spend money on Audition just to remove ground hum. As others have suggested using an EQ would work well.

Yea… but audition comes with a free 30 day trial, which reminds me I am on my last 2 days and have a bunch of old movie samples to get to. However an eq does work but it bay not be as specific and you might end up taking out parts of the sound that you want, for example if you are dealing with a break with some noise over top, if you just try to eq out the high noise you may take the brightness out of the cymbals…

The “reafir” free VST plugin will perform exactly the subtraction you are looking for.

What it does is analyse a hum or whatever you play to it, and builds a spectral analysis of the “noise floor”. Then, when you play samples through it in its “subtract” mode, it will cut out the noise/hum. It’s pretty damn effective, and easily rivals Adobe’s own noise removal.

this thread has been very helpful to me. thank you.