DC offset

what to use

I’m getting a slight but visible DC offset on one channel of my recordings. Is there a post-processor around that will remove it?
I know some proggies allow adjustment as you record, but I want to remove it from some pre-recorded stuff.

Try WAVOSAUR DC removal. However, if it’s very slight and you can’t hear any weirdness, I wouldn’t worry about it. Many sound sources are going to be asymmetrical by nature.


EDIT: The price is right… as in FREEEEE…

Don’t know if this is any good, but it came up in a search…

Or just run a high pass on the file to remove the DC offset.

I got a DC Offset utility on a floppy disk around somewhere…
It installed on win '95 and '98SE…
way back when…
Will it install on VISTA ????
I have no idea…
It’s a DX Plug-in…
It worked like a charm on those Operating Systems…


Adobe Audition (Cool Edit Pro) includes this function in its “Normalize” feature.

Also, Analog-X has a freebie utility for this located - here.

Quote: (Bubbagump @ Jul. 23 2009, 2:36 PM)

Or just run a high pass on the file to remove the DC offset.

As Bubba very correctly pointed out, just use your EQ you already have. That's what these plugins and built-in editor utilities are doing anyway. They just just "examine" the signal and approximate the level of the DC offset and apply a high pass filter to wack the offending DC.

In my haste to help, I didn't think it through. Bubba did...

Here is a good explanation of "DC offset";


DC offset is an offsetting of a signal from zero. The term originated in electronics, where it refers to a direct current voltage, but the concept has been extended to any representation of a waveform. DC offset is the mean amplitude of the waveform; if the mean amplitude is zero, there is no DC offset.

DC offset is usually undesirable. For example, in audio processing, a sound that has DC offset will not be at its loudest possible volume when normalized (because the offset consumes headroom), and this problem can possibly extend to the mix as a whole, since a sound with DC offset and a sound without DC offset will have DC offset when mixed. It may also cause other artifacts depending on what is being done with the signal.

DC offset can be reduced in real-time by a one-pole one-zero high-pass filter. When one already has the entire waveform, subtracting the mean amplitude from each sample will remove the offset. Often, very low frequencies are called "slowly changing DC". While not technically accurate, a high-pass filter can remove such a "changing offset" better because its cutoff does not extend to as low a bandwidth as the above method.

Thanks for the "wake up" Chip. :agree:


EDIT: In the case of severe DC offset, it might be better to use a specific tool designed for the task... but for slight offset, hi-pass it and carry on seems to be the best way.

OK - cool and thanks. I’ll try these out.
It showed up when I silenced a section that was already low level, and I could visibly see a small stairstep from the recorded material to the silenced section.
Kinda like a hair on the camera lens.

Really… to eliminate DC in all cases and for simply a better mix, I nearly always throw an EQ on the 2 buss high passed at 35-40hz. That sub 40hz area limits your headroom often times due to low end rumble or DC offset… plus you can’t hear it… so cut it out. Even better if you can use a linear phase EQ (ReaFIR, CurveEQ, PSPNeon, etc) for the job as you can be very surgical and create a very sharp filter with no resonance… though a minimum phase will do just fine.

However, based on your last post, are you sure you didn’t just slice at a non-zero crossing?

Lastly, another vote for Wavosaur. It is all I use for wave editing anymore.


re Bubba
Or just run a high pass on the file to remove the DC offset.

That's the ticket. A BIG thank you Bubba. :agree:

I know what I am talking about from time to time. :)