sound file not "centred" at zero

[sidavis21]

Hi,
I have been given a sound file which sounds OK to listen to, if a bit quiet. However when I open it up in Audacity and try to amplify the sound I notice that the sound wave is not in the center of the spectrum and amplifying the sound increases the offset. The image below will hopefully give you a better idea of the problem.

screen shot of sound file

soundwave.gif (3.04 KiB) Viewed 488 times

I have tried to rectify this but can't. What's going on? How did this happen and can it be fixed???

Thanks in advance,

Simon

[kozikowski]

Someone produced a sound track with substantial DC or battery voltage mixed in with the performance. This is sometimes caused by a broken sound card or audio digitizer. You can get rid of it with the DC portion of the Normalize tool.

Yes, this problem will cause normal edits and filters to produce damaged results. It may also be why the original file was low level. If you can trace the file back to the origination, you might warn them of this.

Koz

[sidavis21]

Thanks so much this has been bugging me for ages as I keep coming across files with this!!! Really appreciate the advice and yes, the normalise tool does the trick!