removing dc offset per track when mixing

[eatyourguitar]

since there is no "mixing forum" I think its better answered in the mastering forum. I am recording various noises, synths, drones through fuzz pedals and I can see an obvious DC offset in the waveform that I recorded. I have a feeling that I should remove the dc offset to get a better mix. what would you do? is it true that removing a dc offset has no audible difference when soloing that track? is it better to reamp the signal so I get a nice AC signal through the mic. also I noticed lower tones with less harmonics produce a neg dc offset and most of the stuff I feed it above 400hz + harmonics has a pos dc offset. this makes it difficult to fix as my dc offset is moving during the performance.

[Jonathawkes]

Try adding a HP Filter before you record if possible.

[eatyourguitar]

ok like 20hz HPF. you think that will fix it?

[Jonathawkes]

Originally Posted by eatyourguitar

ok like 20hz HPF. you think that will fix it?

Try it out. If 20 doesn't work try 35 or 45. If you're recording vocals I would go as high as 75 or 80. For bass or kick I would go up to 35 or 40 max.

[Cheebs Goat]

Originally Posted by Jonathawkes

Try it out. If 20 doesn't work try 35 or 45. If you're recording vocals I would go as high as 75 or 80. For bass or kick I would go up to 35 or 40 max.

Since DC offset is a 0 Hz signal, would you ever has to hpf as high as 80 Hz to kill it?

[fenderbender.]

Originally Posted by Cheebs Goat

Since DC offset is a 0 Hz signal, would you ever has to hpf as high as 80 Hz to kill it?

No, but it's a good idea especially if you don't have proper low-end monitoring.


OP: if you hear something that bothers you, try to make it better. Use your ears and don't worry so much about potential technical problems. If it sounds good, it is good!

[eatyourguitar]

here is my eq curve. I'm looking at an overlay of the waveforms before and after, they look identical. also I cant see with my naked eye any change in dc. BUT I can totally hear a difference. it almost sounds as though there is some 12k - 14k getting filtered even though my eq is dead flat up there. its more musical now and easier on the ears. this is a welcome side affect in noise and drone music. its hard enough to listen to as is.

[Jonathawkes]

Originally Posted by eatyourguitar

here is my eq curve. I'm looking at an overlay of the waveforms before and after, they look identical. also I cant see with my naked eye any change in dc. BUT I can totally hear a difference. it almost sounds as though there is some 12k - 14k getting filtered even though my eq is dead flat up there. its more musical now and easier on the ears. this is a welcome side affect in noise and drone music. its hard enough to listen to as is.

Did you render the eq to the wav so that you could see what effect it was having?

[dcollins]

Originally Posted by eatyourguitar;

since there is no "mixing forum" I think its better answered in the mastering forum. I am recording various noises, synths, drones through fuzz pedals and I can see an obvious DC offset in the waveform that I recorded. I have a feeling that I should remove the dc offset to get a better mix. what would you do? is it true that removing a dc offset has no audible difference when soloing that track? is it better to reamp the signal so I get a nice AC signal through the mic. also I noticed lower tones with less harmonics produce a neg dc offset and most of the stuff I feed it above 400hz + harmonics has a pos dc offset. this makes it difficult to fix as my dc offset is moving during the performance.

Chances are there is no problem at all. Many instruments are not symmetrical around zero, but this does not mean you need to filter anything. Unless you are hearing pops when starting/stopping playback or at edit points you do not have DC offset problems.

The best thing to do is to stop looking at the waveforms as it is more distraction than help in most cases.

In the rare case of actual DC offset use the lowest possible cutoff frequency, preferably <20Hz.


DC

[RasCricket]

What DAW are you using? I regularly have to remove DC offset and Id need some serious convincing on why someone would ever want to roll the dice with an EQ instead of using a DC offset removal tool tutttutt

Id never suggest to someone, after having dealt with DC offset a lot, that they should some how try to EQ their way out of that mess when theres tools out there that do it in one click. BUT, maybe theres something you guys know that I totally dont - but I unfortunately have to deal with DC offset all the time due to my craptastic sound card.

I use Audition and it has an absolutely perfect tool for removing DC offset and it takes a whole 3 seconds. In Reaper, there is a JS DC Removal tool. And in Reaper, Ill leave the tool in the chain for that track, then when I finally bounce down a final stem for the main mix, bam, its already fixed.

I had to do a bunch of research on it and yeah, it does sound different when solo'd, but you cant tell. What its doing, is stealing your headroom when theres some offset going on. I just deal with DC offset and correct it every single time I record and my best advice by far rather than "guessing" with an EQ - and youll be guessing because DC offset is different minute to minute. One take of mine will be -3.39 off from center then two minutes later, my next take is -3.32. Or even further apart than that.

Use a tool ~ dont guess with an EQ - if you dont have a tool, send me the file and ill have it fixed for you in less than a minute. From my experience, in 2010, using an EQ would quantified as a "guess". I like the "Find Zero" button in Auditions tool - it will very accurately tell you how off from center the DC offset is. thumbsup

EDIT: Yes, it is an issue - get rid of it. Its currently eating headroom that it shouldnt. From my research, its basically your sound card to blame - get a better sound card. Lol, dont be like me. I still make quality productions with an HD Realtek, but you should save yourself the headache

And after reading again, oh my god - you poor man! You were "Listening" trying to fix DC offset and theres also guys here talking about your monitoring???? Lol, come on boys! This is bad advice. REALLY bad advice. He needs to use a tool. Just send the file to me and itll be done properly - without any needless "listening" or "monitoring" at all.

"this makes it difficult to fix as my dc offset is moving during the performance." ~ I could fix this too. All Id have to do, is make a selection over top of each section with a different DC offset, hit the Find Zero button, apply, select the next region of the wav with a different DC offset, and rinse and repeat. Now........does that sound drastically more accurate and easier than using an EQ to try and fix this issue? Yes, it does, lol. The fact that you have alternating DC offset perplexes me. But yes, its easy to properly fix it and Id be glad to help.

[Jonathawkes]

It's good practice to add a HP filter for many reasons.

[666666]

Originally Posted by fenderbender.

...if you hear something that bothers you, try to make it better. Use your ears and don't worry so much about potential technical problems. If it sounds good, it is good!...

Amen, brother.

Originally Posted by dcollins

...The best thing to do is to stop looking at the waveforms as it is more distraction than help in most cases....

Indeed!

Dear OP: I can assure you that some or most of the best sounding albums ever recorded / mastered were done without anyone even thinking about DC offset.

You should probably just stop playing with digital plug-ins and do you work with old-school analog tools for a while. Turn some knobs based on what you're hearing, stop looking at graphs and such on a computer screen.

Sure, it's good to know the technical side of things, but in the end, all that counts is how the music sounds. You really only need to use your ears.

And IF you HEAR a strange audible issue that is puzzling you, then, and only then, take a look at the technical aspects. Though, most of the time, you'd be able to deal with it using only your ears anyway.

[Sempoo]

I think it is not only about DC offset. More, it's about phase rotation. Orban processors use phase rotators, because human voice is often asssymetric.

Maybe try this tool:

Voxengo PHA979/

[eatyourguitar]

yeah so the 15 min performance is done now and I'm pretty sure it was all in my head. the waveform was similar to a squarewave at 80% PWM. so even though it had higher excusion on one side it had a longer period on the other. when you zoom out and look at the silhouette all you see is massive dc but its not true. its just how it draws it on the screen. not enough pixels. I feel really stupid now. but the 20hz HPF is the bitches tits. I'm making it a rule from now on. I think the <20hz was robbing my headroom or somethin. like I said, its a little more pleasant to listen to know. my paranoia is mostly cause its my very first fuzz pedal that I own. rather uncharted territory. thanks yall.

and if i did actually have a moving dc problem, cutting into peices is unaccepable. you can do it on a modular synth with the audio running through a slew limiter and summed/mixed back in with the dry signal. the slew limiter is gonna filter everything above 1hz if you set it properly. just invert the output of the slew and you have your counter dc offset.

[Bubbagump]

The bigger question, if you indeed do have DC offset problems, why? If you have DC offset on every track, this likely means something is wrong in your hardware.... converter gone wonky or something. So make sure it actually is DC offset (which I am doubting it really is) and fix that before you mess with anything else.

[ak23]

Originally Posted by eatyourguitar

since there is no "mixing forum" I think its better answered in the mastering forum. I am recording various noises, synths, drones through fuzz pedals and I can see an obvious DC offset in the waveform that I recorded. I have a feeling that I should remove the dc offset to get a better mix. what would you do? is it true that removing a dc offset has no audible difference when soloing that track? is it better to reamp the signal so I get a nice AC signal through the mic. also I noticed lower tones with less harmonics produce a neg dc offset and most of the stuff I feed it above 400hz + harmonics has a pos dc offset. this makes it difficult to fix as my dc offset is moving during the performance.

voxengo elephant does have a tunable DC offset filter build it.
try it.
but better to find the source of DC.

[RasCricket]

Originally Posted by ak23

but better to find the source of DC.

Always better to find to source of DC offset - I personally have. Its my craptastic HD Realtek and the fact I dont have a MIDI interface.

But heres my latest song to let you know Im not someone who is totally "Fail" at self-productions - I played or programmed every instrument myself: SoundClick artist: RasCricket - Original Reggae and Dub Productions ~ Small Axe Studios

Now....lol, yes I deal with DC offset every time I record, but its manageable. And yes, its cuz I have a HD Realtek soundcard that, well.....sucks. But until I get a better soundcard which would completely alter my award winning setup ~ yes I record all guitar parts without an interface straight into an HP tower's Line In jack ~ Ill be left with dealing with DC offset which requires a simple tool to fix. I know, it sucks....

Ive got just enough talent to make me stubborn enough to take whatevers in front of me and make it work. Great huh?