1 (edited by PierreMartin 2023-09-21 19:31:42)

Topic: RME Fireface UFX III DC Offset when recording

Hello,

I have recently bought an RME Fireface UFX III and didn't had much time to record with it.
I have discovered than I have a pretty big DC Offset when I try to record.

Cubase 12 Pro
2x U87 Ai
no plugins
Gain at 33 on TotalMixFX

See:

https://ibb.co/LgrmL10

https://imgbb.com/LgrmL10

How to get rid of it ? Is my electric installation failing ? I didn't have DC Offset with my former RME Fireface UC in the same installation...

Thanks !

2 (edited by waedi 2023-09-22 00:04:22)

Re: RME Fireface UFX III DC Offset when recording

To me this looks not like DC-offset, it's more a normal wave, not symmetrical.
Nothing to worry about.
Depending on the instrument or microphone it can be more or less symmetric.
I can render a softsynth wave and it looks even more unsymmetric.

This is an image with DC-offset :
https://manual.audacityteam.org/m/images/d/df/dc_offset.png

And this article explains something about it : https://producenewmedia.com/asymmetric- … -concerned

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

3

Re: RME Fireface UFX III DC Offset when recording

Use DIGICheck - BitStat & Noise to see the real DC value.

Regards
Matthias Carstens
RME

Re: RME Fireface UFX III DC Offset when recording

The waveform is not symmetrical, the upper part is not as long as the lower part. I never experienced this

Re: RME Fireface UFX III DC Offset when recording

If you take an old recording and zoom into the wave you will find out every wave is not symmetrical.
By looking at it you may think it's symmetric but by measuring not.
You can zoom in and make a screenshot and check in Photoshop the distances to the center line.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

6 (edited by PierreMartin 2023-09-25 17:15:56)

Re: RME Fireface UFX III DC Offset when recording

waedi wrote:

If you take an old recording and zoom into the wave you will find out every wave is not symmetrical.
By looking at it you may think it's symmetric but by measuring not.
You can zoom in and make a screenshot and check in Photoshop the distances to the center line.

I checked an old record, and zoomed, and it's absolutely centered, everything is fine. Nothing to compare with the screenshot I posted on my first message. I don't understand the problem

Re: RME Fireface UFX III DC Offset when recording

What and where did you record, how exactly were the mics placed and what polar pattern was in use? Could it be related to the off axis response (which can be an issue with large diaphragm mics)?

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2

Re: RME Fireface UFX III DC Offset when recording

Same place same mic same polar pattern etc... the only change was rme fireface uc to rme fireface ufx III

Re: RME Fireface UFX III DC Offset when recording

PierreMartin wrote:
waedi wrote:

If you take an old recording and zoom into the wave you will find out every wave is not symmetrical.
By looking at it you may think it's symmetric but by measuring not.
You can zoom in and make a screenshot and check in Photoshop the distances to the center line.

I checked an old record, and zoomed, and it's absolutely centered, everything is fine. Nothing to compare with the screenshot I posted on my first message. I don't understand the problem

Do you hear a difference ? Is the recording bad sound ? Distortion ? Noise ? Crickle crackle ?

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

Re: RME Fireface UFX III DC Offset when recording

waedi wrote:
PierreMartin wrote:
waedi wrote:

If you take an old recording and zoom into the wave you will find out every wave is not symmetrical.
By looking at it you may think it's symmetric but by measuring not.
You can zoom in and make a screenshot and check in Photoshop the distances to the center line.

I checked an old record, and zoomed, and it's absolutely centered, everything is fine. Nothing to compare with the screenshot I posted on my first message. I don't understand the problem

Do you hear a difference ? Is the recording bad sound ? Distortion ? Noise ? Crickle crackle ?

None of these. No bad sound, ni distorsion, no noise, no crackle.

11

Re: RME Fireface UFX III DC Offset when recording

In post 3 I wrote: Use DIGICheck - BitStat & Noise to see the real DC value.

Instead 7 more obsolete posts were issued that brought zero improvement or clarity on the matter.

Regards
Matthias Carstens
RME