mbuster
New member
When is the best time to remove it? Should it be done on a track by track basis or can I wait until the final stereo mixdown?
TexRoadkill
Audio Bum
It robs you of headroom so the earlier the better. Don't do it unless you need it.
Teacher
New member
DC offset only occurs after i do my DIY mastering...so its always my last step
S
shackrock
New member
what IS this, for real? ha. i mean, i after i hit stop with ntrack after a recording (delta44) - all the tracks end with a huge line going straight up/down before the wav ends. It makes no noise, but it is definately in the picture. haha. anyway, is this what you're talking about?
sonicpaint
New member
DC Offset.
DC offset is when the wave for is off center.
sonicpaint
DC offset is when the wave for is off center.
sonicpaint
R
Rusty K
New member
So visual offset of the wave form is an indicator of the actual audio offset?
Rusty K
Rusty K
sonicpaint
New member
In most cases.
In most cases yes the visual of the waveform will be off center but in some cases the offset is not big enough to see in the wave form. It' best to use an analyzer to see the actual specification of the waveform to be sure.
hope this helps,
sonicpaint
In most cases yes the visual of the waveform will be off center but in some cases the offset is not big enough to see in the wave form. It' best to use an analyzer to see the actual specification of the waveform to be sure.
hope this helps,
sonicpaint
B
bleyrad
New member
analyzer
analyzers aren't always correct though.
all they can measure is the average centre point of the waveform, and guess that the DC offset probably lies there or somewhere around there.
the ACUTAL DC offset is caused only by a voltage offset while you're recording. but the average middle can be somewhere else entirely than where the DC offset is, depending on the shape of the waveform recorded.
that is why you should only correct DC offset if you know for certain there's a problem with it.
analyzers aren't always correct though.
all they can measure is the average centre point of the waveform, and guess that the DC offset probably lies there or somewhere around there.
the ACUTAL DC offset is caused only by a voltage offset while you're recording. but the average middle can be somewhere else entirely than where the DC offset is, depending on the shape of the waveform recorded.
that is why you should only correct DC offset if you know for certain there's a problem with it.
R
Rusty K
New member
I'm getting more confused as this thread goes on. I can obviously see an offset in many of my tracks. Do I have a problem that needs correction or don't I?
I have for a long time wondered why some of my tracks seems hotter on one side or the other. I just chalked it up to my amp channels not being the same or even wondering if one ear was damaged a bit. It always seems to be "left". Does that correspond to an above zero line DC offset cause that's what I usually see in tracks.
In other words does my soundcard offset the same way in each track recorded.......or do I even have a clue as to this subject matter?
Rusty K
I have for a long time wondered why some of my tracks seems hotter on one side or the other. I just chalked it up to my amp channels not being the same or even wondering if one ear was damaged a bit. It always seems to be "left". Does that correspond to an above zero line DC offset cause that's what I usually see in tracks.
In other words does my soundcard offset the same way in each track recorded.......or do I even have a clue as to this subject matter?
Rusty K
B
bleyrad
New member
Rusty,
DC offset has nothing to do with panning.
It only occurs within an INDIVIDUAL, MONO waveform.
If one side is louder than the other, you just have a stereo panning/gain issue that you need to deal with.
DC offset is when a single waveform is biased either above or below the zero-crossing line.
I made a simple (really shitty) illustration to show you.
DC offset has nothing to do with panning.
It only occurs within an INDIVIDUAL, MONO waveform.
If one side is louder than the other, you just have a stereo panning/gain issue that you need to deal with.
DC offset is when a single waveform is biased either above or below the zero-crossing line.
I made a simple (really shitty) illustration to show you.
Attachments
R
Rusty K
New member
ok.....If the amplitude of the wave is offset so that one side of a mono file is larger either above or below the center line then it should be compensated for....right? Is this not audible? If it's visually obvious is that the criteria for recentering the wave form?
I want to know what to "listen" for. If there is no audio difference then why?......just for "headroom" or is my software help file correct when it states that some waveform transforms require a centered wave? So far all my plugs/processing seems to work but I'm now wondering how well, especially things like noise reduction.
Thanks bleyrad,
Rusty K
I want to know what to "listen" for. If there is no audio difference then why?......just for "headroom" or is my software help file correct when it states that some waveform transforms require a centered wave? So far all my plugs/processing seems to work but I'm now wondering how well, especially things like noise reduction.
Thanks bleyrad,
Rusty K
sonicpaint
New member
I don't think anyone said that it did.
As far as DC offset effecting panning, I don't think anyone said that. I know I didn't. They're completely different things. Just thought I would correct that.
Now to an analyzer being off when calculating the DC Offset I'm going to have to disagree with you there bleyrad. I have had no problems correcting wave forms in this area and it has always been correct when I've done it. I know this because I've tried to seperate and diffferent programs and ended up with the same result.
Rusty K, if you are having wave forms that have a large and visible DC Offset, then I would correct it and yes you are having problems somewhere in your recording chain. I'd suggest finding the problem and correcting it. Like bleyrad said, the DC offset is caused by the voltage offset. So there must be a voltage offset somewhere in the chain. Do a process of elimination to figure it out.
sonicpaint
As far as DC offset effecting panning, I don't think anyone said that. I know I didn't. They're completely different things. Just thought I would correct that.
Now to an analyzer being off when calculating the DC Offset I'm going to have to disagree with you there bleyrad. I have had no problems correcting wave forms in this area and it has always been correct when I've done it. I know this because I've tried to seperate and diffferent programs and ended up with the same result.
Rusty K, if you are having wave forms that have a large and visible DC Offset, then I would correct it and yes you are having problems somewhere in your recording chain. I'd suggest finding the problem and correcting it. Like bleyrad said, the DC offset is caused by the voltage offset. So there must be a voltage offset somewhere in the chain. Do a process of elimination to figure it out.
sonicpaint
sonicpaint
New member
What are you using?
What programs are you using?
sonicpaint
What programs are you using?
sonicpaint
B
bleyrad
New member
Rusty,
The problem with DC Offsets is that it's very difficult to actually know when you have one.
You could look for a visual cue but if there is a problem, it's not likely to be so glaringly obvious. More like just a couple percent positive or negative.
You CAN however, tell if you get a DC offset while recording with your gear (the only place one's going to be introduced is by your hardware). Just turn on your preamp, plug its output into your soundcard, and record the sound of silence. Don't plug a mic or anything else into your preamp. Just get the sound of your hardware.
At that point, you have two options. One, you can either use your software's analyzation tools and get it to tell you if there's an offset, because if you haven't recorded an actual source, whatever it tells you will be completely trustworthy. If you don't have that kind of tool, just zoom in nice and close on the waveform and see for yourself if it's biased above or below the centre line. There will likely be a small bit of a waveform there (self-noise from your preamp) but it should be nicely centred around the zero crossing.
DC Offset doesn't really cause audible degredation of your recordings, it just makes it so it won't be as loud. Think about it: if you apply gain to my shitty illustrated waveform there, the top example (DC offsetted) is going to hit the clip point (edge of the box) a lot sooner than the bottom example (no DC offset).
I'm not sure about it affecting plugins - either it means they won't have as much headroom for volume, or they have geniune problems reading and manipulating a DC-offset waveform because it causes math problems or something.
The problem with DC Offsets is that it's very difficult to actually know when you have one.
You could look for a visual cue but if there is a problem, it's not likely to be so glaringly obvious. More like just a couple percent positive or negative.
You CAN however, tell if you get a DC offset while recording with your gear (the only place one's going to be introduced is by your hardware). Just turn on your preamp, plug its output into your soundcard, and record the sound of silence. Don't plug a mic or anything else into your preamp. Just get the sound of your hardware.
At that point, you have two options. One, you can either use your software's analyzation tools and get it to tell you if there's an offset, because if you haven't recorded an actual source, whatever it tells you will be completely trustworthy. If you don't have that kind of tool, just zoom in nice and close on the waveform and see for yourself if it's biased above or below the centre line. There will likely be a small bit of a waveform there (self-noise from your preamp) but it should be nicely centred around the zero crossing.
DC Offset doesn't really cause audible degredation of your recordings, it just makes it so it won't be as loud. Think about it: if you apply gain to my shitty illustrated waveform there, the top example (DC offsetted) is going to hit the clip point (edge of the box) a lot sooner than the bottom example (no DC offset).
I'm not sure about it affecting plugins - either it means they won't have as much headroom for volume, or they have geniune problems reading and manipulating a DC-offset waveform because it causes math problems or something.
B
bleyrad
New member
Re: I don't think anyone said that it did.
Sorry, but that's no valid proof. The only reason they're exactly the same is because they all use the same very, very simple algorithm to calculate DC offset - they take the average middle of the waveform. That's all they CAN do.
The only way you can truly know if your hardware is giving you an offset bias is with the silent-recording method I described above.
It's very likely you're applying correction needlessly, especially if you have decent equipment. Most semi-pro gear won't cause any sort of significant DC offset.
sonicpaint said:
Sorry, but that's no valid proof. The only reason they're exactly the same is because they all use the same very, very simple algorithm to calculate DC offset - they take the average middle of the waveform. That's all they CAN do.
The only way you can truly know if your hardware is giving you an offset bias is with the silent-recording method I described above.
It's very likely you're applying correction needlessly, especially if you have decent equipment. Most semi-pro gear won't cause any sort of significant DC offset.
sonicpaint
New member
I've used DC offset correction in Mastering.
When I have mastered other peoples recording I fixed some real bad offsets. I have never had any problems with it myself. I used to use Cooledit Pro and now I'm using Pro Tools32 with the Digi 002 rack. I never got anything like that with any of these programs or any other hardware I've used in the past either.
I can understand why you feel the way you do about software not being able to make you certain of a perfect correction on an offset. Though I still disagree with you. Keep in mind that I'm not saying that your wrong I'm just saying that I don't agree and this is why.
If DC offset is when the voltage is off-center, then the wave form represented after recording shows the off-centered voltage. So if this is the case and the software corrects the offset, then how can it be wrong? It's not wrong because it's correcting the offset that was recorded.
Now whether you agree with what I just said or not I have a hard time understand why software company's ( sonic solution....etc) would create that feature if in reality the software wasn't correcting the DC offset at all.
Like I said before I disagree with you. I hope you understand that I'm just explaining myself here and not trying to be difficult. I just disagree with you and it's ok for two people to disagree.
sonicpaint
When I have mastered other peoples recording I fixed some real bad offsets. I have never had any problems with it myself. I used to use Cooledit Pro and now I'm using Pro Tools32 with the Digi 002 rack. I never got anything like that with any of these programs or any other hardware I've used in the past either.
I can understand why you feel the way you do about software not being able to make you certain of a perfect correction on an offset. Though I still disagree with you. Keep in mind that I'm not saying that your wrong I'm just saying that I don't agree and this is why.
If DC offset is when the voltage is off-center, then the wave form represented after recording shows the off-centered voltage. So if this is the case and the software corrects the offset, then how can it be wrong? It's not wrong because it's correcting the offset that was recorded.
Now whether you agree with what I just said or not I have a hard time understand why software company's ( sonic solution....etc) would create that feature if in reality the software wasn't correcting the DC offset at all.
Like I said before I disagree with you. I hope you understand that I'm just explaining myself here and not trying to be difficult. I just disagree with you and it's ok for two people to disagree.
sonicpaint
R
Rusty K
New member
sonicpaint,
I'm using Cool Edit.
I am going to try the "record silence" thing and I will report back
Rusty K
I'm using Cool Edit.
I am going to try the "record silence" thing and I will report back
Rusty K
sonicpaint
New member
Looking forward to your post.
Rusty,
I'm looking forward to your post. Unfortunately that test will only tell someone whether they have a DC Offset or not, right from the root. Where the difference of opinion is, whether DC Offset is being corrected when done in a software program. I think it is and bleyrad doesn't.
So I guess it's going to stay at that. For me if I can notice the offset when I look at the wave form, I will fix it. If I can't see it then I don't think it's a big enough problem to do anymore processing then I have to. Though working with Pro Tools does have it's benifits in this area.
sonicpaint
Rusty K said:
Rusty,
I'm looking forward to your post. Unfortunately that test will only tell someone whether they have a DC Offset or not, right from the root. Where the difference of opinion is, whether DC Offset is being corrected when done in a software program. I think it is and bleyrad doesn't.
So I guess it's going to stay at that. For me if I can notice the offset when I look at the wave form, I will fix it. If I can't see it then I don't think it's a big enough problem to do anymore processing then I have to. Though working with Pro Tools does have it's benifits in this area.
sonicpaint
R
Rusty K
New member
Yes and with CE bought out by Adobe I probably should have gone with Pro Tools myself
I've recorded "silence" and there is no waveform visable at all. I also can hear nothing, no noise.
In Cool Edit the fix is with an amplify plugin. I tried it on a session track that looked like it had an offset....trouble is I don't know if it fixed the problem or not since the waveform looked the same after I processed. The only thing I didn't do was save the file and then look at it.
From the posts I've seen on the subject I'm not the only one confused about it. There must be threads on this subject in the archives. I did a search for "DC Offset in Cool Edit" but nothing came back. Maybe I should retry.
Rusty K
I've recorded "silence" and there is no waveform visable at all. I also can hear nothing, no noise.
In Cool Edit the fix is with an amplify plugin. I tried it on a session track that looked like it had an offset....trouble is I don't know if it fixed the problem or not since the waveform looked the same after I processed. The only thing I didn't do was save the file and then look at it.
From the posts I've seen on the subject I'm not the only one confused about it. There must be threads on this subject in the archives. I did a search for "DC Offset in Cool Edit" but nothing came back. Maybe I should retry.
Rusty K
sonicpaint
New member
I love my Pro Tools rig.
I used to be a CoolEdit Pro user to but I was getting sick of the "background mixing" crap. I used to like Cooledit a lot but having that bar always mixing in the background is stupid. I have been using Pro Tools for about 2 months now and I have no regrets at all. I wish I would have started using Pro Tools years ago.
As to your offset problem. When it's an offset that you can see and notice then I'd fix it and I know that many recording engineers would do the same. So if you can't figure out what is causing the DC Offset then just correct it when it gets out of hand.
I wouldn't worry about it too much. You'll figure it out sooner or later just by recording with different hardware setups. It's one of your links in the chain though, so if you don't have too much gear it shouldn't be too hard to find the piece that's creating the offset.
Hope you figure it out.
sonicpaint
I used to be a CoolEdit Pro user to but I was getting sick of the "background mixing" crap. I used to like Cooledit a lot but having that bar always mixing in the background is stupid. I have been using Pro Tools for about 2 months now and I have no regrets at all. I wish I would have started using Pro Tools years ago.
As to your offset problem. When it's an offset that you can see and notice then I'd fix it and I know that many recording engineers would do the same. So if you can't figure out what is causing the DC Offset then just correct it when it gets out of hand.
I wouldn't worry about it too much. You'll figure it out sooner or later just by recording with different hardware setups. It's one of your links in the chain though, so if you don't have too much gear it shouldn't be too hard to find the piece that's creating the offset.
Hope you figure it out.
sonicpaint