Author Topic: DC Offset Cancellation  (Read 41861 times)

David Guy

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DC Offset Cancellation
« on: January 24, 2009, 10:37:10 pm »
What is DC Offset Cancellation? I have the option to use it on my Realtek soundcard - should I?

Paul Sanders (AlpineSoft)

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Re: DC Offset Cancellation
« Reply #1 on: January 25, 2009, 09:35:00 pm »
Hi,

DC (= Direct Current) offset refers to a situation where the entire signal is shifted up or down slightly from the centre line, and DC offset cancellation puts this right by centring the signal around 0.

Here is a signal (much magnified) with a DC offset:



And here's how it looks when DC offset cancellation has been applied (note that it is shifted up slightly):



DC offset rarely causes a problem in practise.  It is usually very minor and cannot be heard as your playback system will filter out any DC component anyway.  That said, it does no harm to enable DC offset correction if your sound card offers it and in severe cases that might prevent a minor 'pop' at the start of the track.  I would use it, personally.

VinylStudio's Rumble filter will also correct any DC offset, but you won't see the effect in the waveform display as filtering is applied only when you save tracks or burn CDs.  To see the filtered waveform within VinylStudio, select 'Save a Copy' from the right-click menu in the File History list in the waveform display.
« Last Edit: January 25, 2009, 11:35:23 pm by Paul Sanders (AlpineSoft) »

David Guy

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Re: DC Offset Cancellation
« Reply #2 on: January 25, 2009, 11:25:12 pm »
Thanks Paul - ON it is!!

Cheers