• Registered: 2019-05-10
  • Posts: 7

Topic: Channel Count Under Core Audio (UFX+)

Setup:
MBP 15" 2017
macOS 10.12.6
UFX+ (connected via Thunderbolt, latest drivers and firmware)

Issue:
w/ the UFX+ clocking @ 96kHz, the channel count under Core Audio is still 94in/94out. This is causing problems when configuring the UFX+ ADAT and MADI inputs in my DAW.

Per the UFX+ manual section 15.4:

It is not possible to change the number of Core Audio channels without a reboot of the com- puter. Therefore whenever the Fireface changes into Double Speed (88.2/96 kHz) or Quad Speed mode (176.4/192 kHz) all channels stay present, but become partly inactive.

Question:
I've tried power cycling my computer and the UFX+ but the channel count under Core Audio is not updated. What can I do to get Core Audio to recognize and report the correct channel count for a device at a given sample rate?

2 Reply by MC

  • MC
  • MC
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Re: Channel Count Under Core Audio (UFX+)

Nothing. The manual explains why it won't work. It was not meant to say that a reboot fixes the issue, sorry.

Regards
Matthias Carstens
RME

MC's Website

3 Reply by goldie (edited by goldie 2019-05-11 02:58:12)

  • Registered: 2019-05-10
  • Posts: 7

Re: Channel Count Under Core Audio (UFX+)

Okay. I assume then that the table from section 15.4 describes how the channels collapse at double and quad speed?

I.e., at double speed, Core Audio channels 55 - 94 are inactive?

And to clarify, there is no circumstance under which the number of Core Audio channels will change?

4 Reply by MC

  • MC
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Re: Channel Count Under Core Audio (UFX+)

Both yes.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2019-05-10
  • Posts: 7

Re: Channel Count Under Core Audio (UFX+)

Thank you.

Just to follow up, I did some experimenting and found that the Core Audio channels were not collapsing as I had expected at double and quad speed.

Instead of the scenario I had outlined above, at double speed the input channels appear as follows:

@96kHz
Input Ch 1-12 (Anlg 1-12)
Input Ch 13-14 (AES 1-2)
Input Ch 15-22 (ADAT 1-8)
Input Ch 23-30 (Inactive)
Input Ch 31-62 (MADI 1-32)
Input Ch 63-94 (Inactive)

6 Reply by MC

  • MC
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Re: Channel Count Under Core Audio (UFX+)

Collapse then seems to be a wrong or at least unclear word. The list is not compressed, no channels are removed. If so there would have been no need to explain all this in the manual!

Regards
Matthias Carstens
RME

MC's Website

7 Reply by ramses (edited by ramses 2019-05-12 08:30:09)

  • ramses
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Re: Channel Count Under Core Audio (UFX+)

goldie wrote:

Thank you.

Just to follow up, I did some experimenting and found that the Core Audio channels were not collapsing as I had expected at double and quad speed.

Instead of the scenario I had outlined above, at double speed the input channels appear as follows:

@96kHz
Input Ch 1-12 (Anlg 1-12)
Input Ch 13-14 (AES 1-2)
Input Ch 15-22 (ADAT 1-8)
Input Ch 23-30 (Inactive)
Input Ch 31-62 (MADI 1-32)
Input Ch 63-94 (Inactive)

I rarely use above 44.1, but this is the expected thing. Only ADAT and MADI channels need SMUX (thus loose 50 or even 75% of channels).
And it's also expected that ADAT and MADI channels always start at their usual starting point / number in the order of channels.

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