Need help with low level hum (audio attached)

[sdsumike619]

I've attached a WAV file that has a low level hum from an open mic. Is there a simple way to eliminate or even lessen it? I'm using Sony Vegas 8. Thanks in advance!

[edDV]

Need hardware info

What Mic? What Mic cable? Connected how? To what input?

[sdsumike619]

Its' a Rode mic, with XLR cable, connected to a Blue Tube, then to mixer, then into a channel on the camera. The audio has already been recorded. I'm just trying to figure out how to lessen this rumbling sound. I think I can do it with EQ, but I need to determine what frequency and bandwidth it occurs at. Is there a way to determine that?

[edDV]

Its' a Rode mic, with XLR cable, connected to a Blue Tube, then to mixer, then into a channel on the camera. The audio has already been recorded. I'm just trying to figure out how to lessen this rumbling sound. I think I can do it with EQ, but I need to determine what frequency and bandwidth it occurs at. Is there a way to determine that?

I could help track down the original problem but...

Hum usually occurs at 60Hz power frequency so to eliminate you would low EQ filter out 60Hz. Set pass threshhold above 60Hz.

This usually doesn't hurt an isolated voice track but can mess up music.

[luigi2000]

Sounds like air conditioner noise. To start, typically roll off spoken dialog below 250 Hz and above 10,000 Hz at 12 dB/octave. Adjust to taste.

[poisondeathray]

You don't have to limit yourself to Vegas' toolset or blindly guess what frequencies the noise occurs at . Audacity (free) has an ok noise removal plugin. You capture a section footprint that is primarily the background noise you want to remove, then apply the filter to the entire piece . Your specific sample has a section with primarily noise only (speaker isn't speaking at that point) , so I would sample from that section . The more aggressive you use NR, the more artifacts and distortions occur, but even a mild NR setting can improve your recording without distorting the speech too much .

EDIT: attached audacity export. This is by no means a great job, but just to demonstrate you can reduce the background noise a bit. You can notice that the speech is slightly distorted, so perhaps lowering the settings would have been better. If you use better software like audition , soundforge or similar software you have more control and can get better results

[sdsumike619]

Used Track EQ, picked the (1), set Frequency to 243, Gain to -Inf. and rolloff is on 12. It eliminates the rumble and takes a little bass out of the voice. I did have some recorded music on the same track so I just moved that audio to a separate track so it wouldn't be affected. Attached another section after the above settings were applied. Much better than what it was for a quick fix.

[sdsumike619]

Poison, when I listen to yours, it sounds like the low rumble is cut out between words, but still there when he's speaking, like an on/off type of thing. I think the one I did with Vegas is ok. I had the audio playing and used the slider to move up the range until I heard it disappear for the most part.

[luigi2000]

That sounds just fine.

[hech54]

Need hardware info

What Mic? What Mic cable? Connected how? To what input?

I'd still love to know how any of this info you requested is supposed to help
filter out the hum?

[edDV]

Need hardware info

What Mic? What Mic cable? Connected how? To what input?

I'd still love to know how any of this info you requested is supposed to help
filter out the hum?

Because his original post could be interpreted as a recurring production issue. He didn't say "The audio has already been recorded" until later. He was complaining about hum. It should be fixed at the source.