hum during live recording

[rasallover]

Hi there

did a live recording with Audaicity the other day and noticed a hum during the recording, is there any way of editing it out with a noise compressor or something similar

here is the sample file:

http://killaloerecords.com/fliss-live1.mp3

thanks so much
Ras Allover

[kozikowski]

We'll see after it comes down. If it's hum, it's a piece of cake. If it's buzz, you have a damaged recording.

It's never hum.

Koz

[kozikowski]

OK. It's open-shield microphone buzz. By my count there's 10 to 15 significant individual buzzy tones in there (60, 120, 180, etc. etc) and you have to get rid of all of them -- without using the Noise Reduction tool. Noise Reduction is the obvious choice, but there's no place in the performance where everybody shuts up and there's buzz completely by itself -- a requirement for the tool.

You need to fix the microphone if you haven't already. This is going to be a painful fix (with existing tools).

Koz

[rasallover]

well the recording is already done so I suppose I would have to go in and edit all the parts inbetween the music

[kozikowski]

The interstitials, yes. You could cheat and not tell anybody. At the end of each song, fade out just slightly early, leave some forced blank time or make up something that would logically be there and then fade in the next song a little late. Maybe a little non-noisy audience from a different show. Something like that.

You can also do this the "correct" way by applying Effect > Notch Filter for each of the frequencies. I was up to four filters ( 60, 120, etc) when I figured it was eventually going to succeed and gave up. I used a "Q" value of 10 to make sure of the least amount of damage. It sounded better and better as I applied more and more filters.

Up to you.

Koz

[rasallover]

sounds good, thank you so much. out of interest, do the filters go up in values of '60' ?

[steve]

out of interest, do the filters go up in values of '60' ?

In the US, mains electricity has a frequency of 60 Hz, which is the cause of "mains hum". However, the "hum" also has harmonics of that frequency. The harmonics are at exact multiples of the "fundamental" frequency, hence 60, 120, 180, 240....
In the UK and much of Europe the "fundamental" frequency of mains electricity is 50 Hz, so the harmonics go 100, 150, 200, 250 ....

[Trebor]

Steve's de-hum plugin does that ...

Steve's de-hum plugin settings.png (31.16 KiB) Viewed 1702 times

''you're fine'' intro before-after Steve's dehum plugin.mp3

(976.33 KiB) Downloaded 263 times

[steve]

Steve's de-hum plugin does that ...

Wow. that's quite impressive - I'd forgotten all about that