• jm345
  • ADAT user
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  • Registered: 2018-08-22
  • Posts: 10

Topic: Digital input connection advice for the UFX II

Just got the UFX II. Very nice unit and TotalMix is great! One device I am connecting as an input is a Fractal Audio AXE-FX III guitar processer. I am wondering the best/cleanest connection option? I assume digital to digital would be best? The AXE-FX III has SPDIF (RCA) and AES/EBU digital outputs and uses 48kHz. The simplest stereo connection looks to be via AES/EBU with a single AES/EBU 110 ohm XLR cable. Does that make sense? Output from the UFX II is to my PC/DAW via USB and/or to FRFR monitors via the XLR 1&2 main outputs.

The UFX II User’s Guide states this, “AES/EBU (and SPDIF) can contain Emphasis information. Audio signals with Emphasis have a high frequency boost, requiring high frequency attenuation on playback.
An Emphasis indication gets lost as there exists no standardized interface on computers to handle this information!”  Is this of any concern for my application? Thank you.

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Re: Digital input connection advice for the UFX II

In 30 years of digital recording, I have never seen a recording with the emphasis flag set.  It was seen to have some use in early low-bit digital recording to effectively improve high-frequency resolution, much the same way as emphasis was used in alanog transmission over FM radio links.  Its appearance in standards is a legacy thing. Forget it and assume that it is not needed.

If you are concerned that it may exist, use the DigiCheck bit meter to confirm the state of the emphasis flag at the time of transfer. If needed, it is a very simple, single time-constant rolloff ... but it won't be needed.

De gustibus - et sonus - non est disputandum
  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,705

Re: Digital input connection advice for the UFX II

No modern converter or device uses emphasis any longer. This is something from the early days of digital recording, some early CDs may still have it, and if you were to copy such a CD to an SPDIF input, you might see it. Else, nothing to worry about it.

Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

  • jm345
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  • Registered: 2018-08-22
  • Posts: 10

Re: Digital input connection advice for the UFX II

Thank you for the info about emphasis.

Any thoughts/benefits about using AES/EBU with the FX III to UFX II instead of using the regular analog connections? Thanks

  • ramses
  • DAW Mastermind
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  • From: UTC+1
  • Registered: 2012-10-14
  • Posts: 12,886

Re: Digital input connection advice for the UFX II

jm345 wrote:

Thank you for the info about emphasis.

Any thoughts/benefits about using AES/EBU with the FX III to UFX II instead of using the regular analog connections? Thanks

Digital connections saves potentially unnecessary ADDA conversions.

I would assume that RME uses the better converters than the FX III and make the most out of a chip by proper circuit design.

Next you save some time for ADDA conversion if the signal stays digital.

Disadvantages of using digital connection could be if the FX III should be unable to receive clock from the UFX II, as RME has a better much advanced clock (steady clock ).
Or from handling perspective in a guitar rack if you want to be able to reduce volume by using Potis for input gain or output level.
My Lexicon MX200 only supports this when not using digital connections.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13