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DC offset. how can i measure it. what is the cause
Old 12th June 2018
  #1
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Thread Starter
DC offset. how can i measure it. what is the cause

Hi i just opened a session recorded in protools (2018) 96k 24bit and noticed a lot of the wavs are off center. how do i measure to see if this is DC offset.

I have been recently using a location with below average conditions for power could this cause it.

Does Offset do anything other than reduce headroom.

I recently noticed that my sessions were harder to edit since changing my system. i upgraded interface and Protools. i thought i was imagining it but would a DC offset problem create more clicks and pops at edit points etc.
Old 12th June 2018
  #2
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Thomas W. Bethe's Avatar
What instruments are you recording? Certain instruments, like brass, can show "off center" waveforms. Most programs today have a plugin or app for removing DC offset. I thought ProTools had one. See https://www.youtube.com/watch?v=gGul6j8y0pw

FWIW I use Wavelab and the Remove DC offset works GREAT!!!
Old 12th June 2018
  #3
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Thread Starter
Thank you.

Yes iv seen uneven waves with Brass before. its on vocals this time and there is a DC offset plugin in PT.

I don't want to presume i would like to see if there is any off set. Is there a way to test.

I would like to learn a bit more about it rather than just applying a fix
Old 12th June 2018
  #4
Go to a local Harbor Fright store and pick up a cheapo 3 buck DVM. Then measure your audio feeds.
Old 12th June 2018
  #5
Gear Maniac
 

Un-plug all inputs to the AD converter, record something and see if there is any DC off set. Chances are there will be none.

You can easily remove DC off set in the recording with a low cut filter set to single digit.
Old 12th June 2018
  #6
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stinkyfingers's Avatar
 

Quote:
Originally Posted by jp1234 View Post
I thought i was imagining it but would a DC offset problem create more clicks and pops at edit points etc.
Yes.

Quote:
Originally Posted by jp1234 View Post
I don't want to presume i would like to see if there is any off set. Is there a way to test.
You could use a spectrum analyzer. If the frequency range goes low enough and the fft size is large enough, you should see something at 0 hz +/- (Span shows it at 1 hz w/32,768 block size)
Old 12th June 2018
  #7
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Thomas W. Bethe's Avatar
Quote:
Originally Posted by jp1234 View Post
Thank you.

Yes iv seen uneven waves with Brass before. its on vocals this time and there is a DC offset plugin in PT.

I don't want to presume i would like to see if there is any off set. Is there a way to test.

I would like to learn a bit more about it rather than just applying a fix
Did you watch the video?

There is a ton of information on the WWW about DC offset and how to manage it.

Some info here:

Understanding DC offset

https://www.sweetwater.com/insync/wh...-daw-software/

https://manual.audacityteam.org/man/dc_offset.html

and a blog DC Offset, what causes, how to prevent - Avid Pro Audio Community

and right here on GS. That is why it is a good idea to search before posting a question.

what is dc offset?

Hope this helps. The WWW is full of information all you need do is search for it.
Old 12th June 2018
  #8
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Thread Starter
Thanks for all the info ill check out. I didn't watch the video i saw it some of my own recording before.
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