Removing hum from audio

Hello. I record concerts with a Canon Powershot SX280 and the white noise when there is silence on stage is loud, as so is the vent noise from the stage of the club we go to alot. I did see how to remove audio from a audio clip, but what I am getting is audio being silence where I just highlight it, as the sound continues, that I am trying to eliminate from the audio. Here is a youtube video During the video, after the 43 second mark, you can hear a slight hum. Which is the vent work. Is there a way to completely take that off the audio track, as then I can sub it back on to my complete video with movie maker. I extract the audio from the video clip with T Audio Converter. Thanks for any help. Mike

Is there a way to completely take that off the audio track

My guess is no. The Noise Reduction tools need a second or two of “pure noise” as a sample. Noise by itself with no other sounds. Any of the other sound management tools might delete the vent noise, but will also destroy musical tones that happen to match the vent sounds.

If you do this all the time, scope out a different seat further from the vents. Best is get the venue to give you a copy of the House Mix. If you’re rolling in bucks, you can bring a shotgun microphone much less likely to pick up anything not in front of it.

Audience captures fail a lot more than they succeed. The microphone overloads, the hall echo is terrible and the man next to you starts opening a bag of chips.


Thank you Koz. Basically, I was using a Canon SX230 Camera for a long time in recording concerts as the “white noise” it produces was way less than the Canon SX280 camera I have also. Canon Admitted to me that the 230 has less white noise effect. I used the 280 Saturday for a concert, as the 230 is starting to have alot of clicking noise from the darkness in the club. So I am going to try to find a new camera like a powershot, as it the camera has to be small, where the white noise is much less. Thanks again for the reply, as I thought this might the case. This is a concert I recorded with the SX230 as the noise is nill. Maybe find a nearly new SX230 on Amazon, as the camera is no longer made, maybe. Mike

If you turn-up Audacity’s spectrogram to the maximum-resolution, you can see the constant sounds from the fan/motor.
You can then manually notch-out the worst* offenders using Audacity’s spectral edit tools

[ * Like Koz says, if you notch-out too much it will damage the music ].

BTW making the audio almost mono makes the general-noise less-obtrusive IMO.

Hi Trebor, Thank you for the reply. I will make a copy of the audio clip and try what you write. My XS230 camera has less white noise and picks up the vent system less in the club than the SX280 for some reason. I can live with the hum, as I think a new camera will pick up the hum of the vent system too, not share how loud until I actually invest 300 or more for a new camera. However, I do see a new SX230 on Amazon, as this is my 2nd SX230 I have. I wore out the card inside the camera, as it was my all around camera for taking pictures. So now the 2nd one I have is just for concerts. But then it gets some tapping noise from the camera doing things, as I have the auto focus off. Anyway, thank you so much for what you wrote. This is the sx230 from a different venue a week ago. No hum, no vent system. I do make a DVD and CD from the audio of my shows.

Official concert-footage usually has audio direct from the performer(s) microphones.
No camera-microphone is capable of replicating that, even if you’re in the front-row of the audience.

YouTube will make stabilized versions of uploaded videos for free,
(when I have done that I chose to keep the original video on my YouTube channel, rather than replacing it with the stabilized version).

Thanks again for the reply, Trebor.

I will let you know how it all works out with the suggestion of removing the hum. Its actually not that bad with the camera I used for the concert Saturday. Again, my other concerts I recorded with the SX230 has less pick up of the vent and white noise for some reason, not sure why.

I can not figure how to do the below:
To define a time range change the track to Spectrogram view, hover at a vertical position that you want to be the approximate center frequency to act on then click and drag a selection horizontally. A horizontal line appears beside the I-Beam mouse pointer that defines the center frequency.
Drag vertically (with or without continuing to drag horizontally) to define the bandwidth (range of frequencies) to be acted on. A “box” containing a combined frequency and time range is now drawn in a colored tint as shown below (the exact color of the tint will depend on the version of Audacity and the settings of your monitor):
Again, thanks for the help. I actually watched the whole 1 hour and 45 minute DVD I made, as again, I have recorded many concerts and put on Youtube, as this is a different camera that picks up more white noise and the vent system, but its not that horrible, the noise. A complete concert at the same venue with the older Canon SX230 camera with very little noise, Its weird that the SX280 picks up more of the noise.
like this, but okay, it will have to be like this if I can not figure out the Spectrom work. The audio with the SX280,. Thanks again, Mike

To put a “box” around the part of the spectrogram you want to change,
you have to “enable spectral selection”: tick that box in “spectrogram settings” …

''Enable spectral selection''.gif
You need to increase the spectrogram-resolution, (“window size”), to the maximum to be able to see the constant sounds created by the fan/motor. When you do that your computer will have more work to do and Audacity may become sluggish.

Thanks for the reply and help as it is much appreciated it. I will see what I can figure out. If I can’t, I will have to accept the audio for what it is.


I did figure out how to get the spectralgram and yes, I have it in full screen, but after that I can not follow your video you made for me, as its is so small to see and so fast. I am using my original Audio track, of 29 minutes, as I do see a white area at the bottom of each track, as I am not sure that is the fan noise? Again, you have gone out of our way to help me. Mike

I have figure out how to get the blue line, as I assume this is the fan noise? But I do not know how to delete it. My Audacity program looks a little different from the demo you have kindly sent. My version is 2.1.3

You need to change the numbers of “Gain”, “Range” & “Frequency gain” in the “Colors” part of the spectrogram-settings to this …

The fan-noise consists of at least ten (horizontal) lines which are constant throughout the recording.
The right side of the picture above shows the “after” where I have notched-out five of them, around 480Hz -570Hz.
There are more noise lines : the give-away sign is they’re unbroken …

before-after (Not Audacity Spectrogram).gif

Delete it using “Effect > Spectral edit multi tool”, which is a notch-filter.

Thank you Trebor. I will take a look at this recent reply from you and give it a try again when I have a bit more time to sit with this, probably later today. Again, I appreciate the help. Mike