I don't know about you, But I LISTEN to music.

Post an example please.

sound pretty much like dc offset?? but yeah might post a pic or something

Greener wrote: I don't know about you, But I LISTEN to music.

Post an example please.

I had the exact same thing happen to me a few weeks ago. I tried this technique to solve it, but after I listened to it, it still looked exactly the same :? I think a different solution might be in order.

btw, it does sound like DC offset to me as well, I just don't know how to fix it yet.

Depends what the waveform was of, as well. Some instruments with very hard attack, like trumpets, for instance, can often look just like that. It may not be anything to worry about. What does it sound like?

The OP mentioned that the song was mixed down, so it would not be an individual instrument.

The problem with the "what does it sound like" kind of question is that you probably would not hear DC offset. But just because you cannot hear it does not mean it is not a problem. It becomes a problem when you try to get the track up to a decent level.

One solution to the problem is to set a HPF at 20-30hz, really steep. I have not tried this yet, but I did sleep at a Holiday Inn last night, so it might work.

Good luck

Here is a picture of the waveform...

I looked up DC offset and it looked like that is when the "Center-line" shifts but the waveform is still symmetrical. As you can see, the waveform isn't symmetrical, it looks like something cut off the top half.

I can't hear anything in the mix that matches what I am seeing.... not that the mix is perfect or anything.

I'm not even sure I should worry about it. I normally don't pay too much attention to how the waveform looks, but this was so drastic I had no choice but to notice.

edit:
Here's a link to the mp3
[[url=http://[/URL]="http://www.soundcli…"]the mix[/]="http://www.soundcli…"]the mix[/]

This happens with some instruments. Even some voices are like this that I've seen.

Codemonkey wrote: This happens with some instruments. Even some voices are like this that I've seen.

But the whole mix? None of the individual waveforms looked like this (drums, vox, guitars, bass)....

Maybe I shouldn't worry about it?

DC offset, means w/e u recorded this with doesnt like your computers mic input on the back

multoc wrote: DC offset, means w/e u recorded this with doesnt like your computers mic input on the back

I recorded most of it with a Firepod (acoustic, electric, bass, vox)... and the drums through a digi 002 (I think.... recorded a friend at his place).... so I don't see how the mic input on my comp. would make a difference. Please elaborate.

I could believe a single mic channel could look like this (although I would say the polarity is the reverse of normal), but a mix of several channels, no. There's something not right there. It looks like a compresser is working on only the positive half of the waveforms.

Try mixing it again with all the input channels phase-flipped but nothing else changed. If the mix picture inverts so that it is predominantly in the positive half, then all is OK. If the result looks much the same as now, you need to start trouble-shooting.

I'm only listening on a lappy, but I can't hear anything drastic in that. Good singing, BTW. You?

hackenslash wrote: I'm only listening on a lappy, but I can't hear anything drastic in that. Good singing, BTW. You?

Thanks, yeah that is me.

Well, I think I fixed it...

I took the track to a friend who has Adobe Soundbooth CS3 today and ran the "remove noise>rumble" filter (saw this as a fix when I was searching for dc offset... I'm guessing I could have used the HP filter like someone suggested earlier). Anyway, I applied the filter and now the waveform looks normal (doesn't really sound different to my ear). So I guess it was DC offset on the entire mix.... weird.

Thanks for all your help everyone...

No, I don't think that was DC Offset. Something like that could only happen with DC Offset, I reckon, if there were a different amount of offset from track to track before mixdown. I could be wrong about this, as I'm just spitballing. In any event, it would be a simple matter to check. Simply remove DC Offset on all your constituent tracks and then run the mixdown again.

hackenslash wrote: No, I don't think that was DC Offset. Something like that could only happen with DC Offset

No, I don't think that makes sense.

And from previous, removing noise>rumble _IS_ an High Pass Filter.

Greener wrote: [quote=hackenslash]No, I don't think that was DC Offset. Something like that could only happen with DC Offset

No, I don't think that makes sense.

And from previous, removing noise>rumble _IS_ an High Pass Filter.

Linguistically, or technically?

You said "I don't think that was DC Offset" then you said "Something like that could only happen with DC Offset".

Which one is it?

MarkG wrote: but I did sleep at a Holiday Inn last night, so it might work.

Good luck

;) It didn't go unnoticed....

Greener wrote: You said "I don't think that was DC Offset" then you said "Something like that could only happen with DC Offset".

Which one is it?

Read my post again. I said, Something like that could only happen with DC Offset if. It does make sense if you read the whole sentence.

Something like that could only happen with DC offset if each constituent track were offset by a different amount. I'm still not sure that this is technically possible, but my statement did make linguistic sense.

When in doubt, HPF everything at 5Hz.

:lol:

Hacken', sorry. I was confused.

I'm still confused, but you are right, linguistically it makes sense.

Still not convinced that it would cause a waveform like that, though. Just the only thing I could think of.

Hello all..

I am sort of experiencing the same situation however let me explain the setup:

I am experimenting with a PreSonus 2 channel BlueTube pre-amp. So my chain goes; Condenser Mic > BlueTube Pre > MOTU 896HD > Mac w/Cubase Studio 4.

When I record with just the phantom power, I get the previously descried "melting" wave form. When I press the Polarity Reversal switch, and re-record, it fixes the problem. Can someone explain this?

The second issue I am having is, the wave form shown in CS4 is really really tiny. The sound that comes from playback is crystal clear and sound good in terms of volume, however there is very little recognizable wave form. Any thoughts?

You've recorded it very quiet. If you are working in 24 bit, this isn't much of an issue. You can simply turn it up.

It reads like you have collapsed the pane view, ya know? Grab a border with your mouse and resize it.

I don't have much ass to boast about my engineering chops but I have recorded in 16 and 24 bit and apparent loudness didn't matter to which one ;)

Space wrote: It reads like you have collapsed the pane view, ya know? Grab a border with your mouse and resize it.

I don't have much ass to boast about my engineering chops but I have recorded in 16 and 24 bit and apparent loudness didn't matter to which one ;)

It matters a deal more in 16 bit, as it has less footroom than a 24 bit system, which is to say that the noisefloor is much higher (by 6 dB per bit, loosely speaking). What this means is that if you record very quietly in a 16 bit system and then raise the level on that track, you're bringing the noisefloor up to somewhere that it will be audible. In a 24 bit system, the noisefloor is so much lower that it is still at an inaudible level for much much longer when the level of the track is increased.

...but the noisefloor of the gear itself could be above or below the 16bit line.

Technically this means you could have a noise free recording if your 16dB converters have a noise floor of less than 96dB?

I've made "adequate" recordings that noone complained about using a pair of computer inputs. 44.1, 16 bit, 60dB of footroom from the computer and badly configured gear.
Lo and behold, they worked.

Absolutely, same here. In fact I used to do all my recordings at 16/44.1 when disc space cost more. At lower bit depths, there is milage in getting hotter signals to keep the noise floor as low as possible, while in higher bit depths, it's less critical.

Would help if the gain structure was set right back then. The noise floor of the preamps was probably half the problem.

I swear the final mix actually ended up as a lovely blend of local radio stations and white noise.

Now, however, I can get away with making 20 min talk recordings on a Creative PCI card.

Anybody got any interesting ideas on this yet? I'd be really interested to know what caused this.

"I'd be really interested to know what caused this."

Gremlins.

Delete the Presonus blue tube. You are feeding a preamp into another preamp and have probably inadvertently got something goofy going on like double phantom power, poor gain staging, or just a defective presonus.