DC Offset

Discussion in 'Production' started by freeagent, Feb 22, 2004.

  1. freeagent

    freeagent Almost 30

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    Paraphrased from the Wavelab Help File, a DC offset is when there is too large a DC (direct current) component in an audio recording. If the DC offset is really bad, it can be visible as the signal not being visually centered around the "zero level axis". However, the DC offset can be significant without actually being seen. DC Offset almost never happens in the purely analog domain, but occurs quite offten in the digital world. The cause of this offset is the different DC currents present in different digital processors.

    I have been going through all my wavs and eliminating the dc offset (by selecting the entire wav in Wavelab and then selecting Process|Eliminiate DC Offset, then Oking at the prompt). My offsets were anywhere between -0.075% left and right to 2.6/3.5% left/right. Removing this offset improved my headroom, and in some cases even made my recordings sound crisper and louder.

    (y) (y) (y)
     
  2. M-Code

    M-Code Hubbidy Hibbedy

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    I remove DC offset more often then not (when i remember). I can't think exactly what it is but it affects a loudspeaker's linear movement in a way which isn't good for it. Or something like that :p
     
  3. freeagent

    freeagent Almost 30

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    Yes, it takes the speaker off its center axis or zero point, which can cause clicking and phase issues (bad bad tings).
     
  4. sdm

    sdm This is Dog Fort

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    I'll do this in future! :slayer:
     
  5. Affliction

    Affliction thought size didnt matter

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    DC offset can also be removed with any high pass filter.... if you think about it a DC offset is just like an ultra low pitch sound wave..... something in the region of 0.00000001 Hz (thats a made up statistic but illustrates my point)

    Good mixing practice dictates putting a high pass filter on everything anyway - but i agree it's still best to do it on the raw samples.

    As a side note those "Remove DC Offset" features in programs like Wavelab / Soundforge are also just high pass filters..... If you wanted to be particularly obsessive about sound quality you'd shun those "inferior" basic filters and use something like the Waves Linear Phase EQ.... But you'd have to be a *proper" audio geek to do that :weirdo: :jerkit: :gimp: :oops:
     
  6. freeagent

    freeagent Almost 30

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    Interesting, but I'm not that obsessive :)