Can I use a High Pass Filter to get rid of an acoustic hum?

The acoustics in my booth have changed and I am noticing some frequencies ‘ringing’ in there.

A high pass filter at 750hz 6dB roll-off seems to fix it pretty well. But I’m afraid that might be too much. It passes the AXC check…but I don’t know if it will pass the real QA check on ACX and get bounced back.

I’m not sure what the problem is, but I am still searching for it.


high-pass is too blunt a tool to combat resonance (ringing):
filter curve is capable of the precision required.

Plot spectrum will show where the problem lies:
This example is a booth ringing at 147Hz …

Thanks for the response. I’m not familiar with using that function. Is there a way to find out more about what it does? I’m looking at about 6 hrs of audio.

“Plot spectrum” shows the relative amounts of each frequency in the audio
https ://

Any resonance (ringing) will show up as a peak on the graph.

(comparing the spectrums of the booth audio before & after the problem appeared will make it easy to spot)

Plot spectrum does not make any corrections, you have to do that manually via filter curve , Graphic EQ, or other equalizer plugin.


What is the best way to put that in my chain? I assume to take the frequency out early, then go about as normal?

This is what I am using…

EQ (adjusted)
Loudness Normalize
Noise Reduction (6,6,6)

…Also…what about a Notch Filter? Can that work as well? If so, how would that figure in to a chain?

Thanks again!

Attenuate the the ringing frequency, rather than take it out completely, (ideally dynamically).

The change produced by a notch filter is a very deep cut, which will make the speech sound abnormal.
notch-filter cuts deep.gif

I was able to figure out the Frequency was at about 190-210 Hz…(a voice sweet spot). It is going to change the sound, but it think it will be ok.

passes specs, just not as full as I would like.

Would you mind giving it a listen to see how I did?

My mic arm was ringing like a tuning fork.

If the unwanted tone is a very narrow frequency band, then “Spectral Delete” might work well. See:
For the narrowest possible filter band, the frequency selection should be just a line (zero height region).

That’s radical surgery: I suspect you’ve amputated more that was necessary to save the patient.
radical surgery.jpg

I put the chainsaw away and tried a scalpel this time. :wink:

Any better?

this was the problem sound

Don’t throw away the mic boom*, that just sounds like standard booth resonance ,
(in your case the main offenders 158Hz & 316Hz )

[*Changing the position of the mic in the booth can make resonance better or worse].

This is so helpful! Thank you!

There are free EQ plugins which can be used to quickly fix the problem e.g. …

I only just discovered the centre frequencies of the sliders in that plugin can be changed …
Voxengo GEQ.gif
If you want a free plugin for dynamic EQ, (i.e. multiband compression)
see …