Hum on soundtrack

I am using Win8.1 on a Toshiba laptop. I have recorded on to Audacity, but on playback there is a disturbing hum. Can this be eliminated?

If this is “traditional” 50/60Hz power line hum, try a notch filter at the appropriate frequency where you live (i.e. 60Hz in North America, 50Hz in Europe). Or, if it’s a voice recording and you don’t need deep bass, you can use a high-pass filter at 150Hz or so to eliminate low-frequency hum.

To prevent power line hum in the future, try running your laptop from its internal battery. This can sometimes eliminate a ground loop, and it will eliminate the computer’s external power supply as a source of hum.

For other kinds of background noise, try [u]Noise Reduction[/u]. If you have a low-level constant background noise, noise reduction can work well. But if the noise is bad, too much of the good program material may be removed/damaged and “the cure can be worse than the disease”. It’s just something you have to experiment with to see if you can make an improvement.

It is best to prevent noise in the first place. We may be able to give you some suggestions if you tell us about your hardware setup… What you are recording from (built-in microphone, an external audio interface, USB turntable, etc.) and how you are connected, etc.

You want us to do it in Post, post production, but we’re going to want to do it in Pre, as you’re making the recording. There are filters that can remove hum from a recording, but they all cause damage. Any tones or sounds in the show that sound anything like hum will be removed as well.

So what are you recording and how are you recording it?

http://www.kozco.com/tech/audacity/Documents/PostingQuestions3.pdf

Koz