Topic: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

Hi! I have a question to those using multiple format outs in RME interfaces.

My studio keeps growing, and within the idea of perpetually trying to upgrade with the next reasonable path ahead of me, it seems that grabbing 2 extra channels for the UCX 2 in reference quality converters, in form of an ADI-2 FS, seems reasonable at a glance.

I only want to send my final mixes out for a loop through a great compressor that I just got and back to finish ITB, and have this path ready to increase a finishing chain at the end of my hybrid setup.

Now here's the catch:

Monitoring is accomplished through AES/EBU since the Fireface is connected to a Neumann KH750 setup, and the ADAT connections are populated with the rest of my analog gear through the 8 I/Os of a Motu 8-pre es.

That leaves me with the single option of a nice I/O loop through SPDIF/RCA connections of the UCX 2.

Now here's the question:

The UCX 2 manual states that if I connect something through SPDIF/RCA, the ADAT outs will also change to that format. Is the whole setup going to implode if I tell it to send SPDIF for a loopback while also monitoring through AES and keeping other 8 I/Os in sync through ADAT, or is it reasonable to believe both ADI-2 FS and UCX 2 will just connect perfectly through SPDIF/RCA and the whole rest of the setup will be taken care by Total Mix?

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

Hi
In my opinion you misreaded something. Optical ADAT (8 channels), AES over XLR and SPDIF over RCA are independent from each other and work in parallel.
It’s only, that the optical i/o ports can also be used for SPDIF signals if needed.

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

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

From page 18 in the user manual UCXll :

The optical TOSLINK output can operate
as ADAT or SPDIF output. ADAT: in-
cludes channels ADAT 1 to 8. SPDIF: in-
cludes channels SPDIF opt. L/R, in To-
talMix ADAT ½. In SPDIF mode Channel
Status is fixed to Consumer.

Nothing will implode when you switch from Adat to SPDIF. Only the Adat output will no longer transmit 8 channels, only two.

The rest stays normal, AES output still send the signal to your speakers.
Also Totalmix keeps its functionality.

No worry, you can ad a ADI-2 to the UCXll for your external mastering compressor, no problem.

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

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

oli77sch wrote:

Hi
In my opinion you misreaded something. Optical ADAT (8 channels), AES over XLR and SPDIF over RCA are independent from each other and work in parallel.
It’s only, that the optical i/o ports can also be used for SPDIF signals if needed.

Hi, thank you for the answer Oli! I was checking TotalMix for that, I guess what's puzzling (and that's in both manuals, ADI-2 FS and UCX ii) is that if you adapt the SDPIF/RCA to use it as AES, it takes over the first 2 ADAT outs and changes the ADAT ports to SPDIF consumer?

That section of the manual is very puzzling, could really be I just misinterpreted the whole thing and as long as I do RCA to RCA and SPDIF everything coexists? Are you using a similar setup?

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

waedi wrote:

From page 18 in the user manual UCXll :

The optical TOSLINK output can operate
as ADAT or SPDIF output. ADAT: in-
cludes channels ADAT 1 to 8. SPDIF: in-
cludes channels SPDIF opt. L/R, in To-
talMix ADAT ½. In SPDIF mode Channel
Status is fixed to Consumer.

Nothing will implode when you switch from Adat to SPDIF. Only the Adat output will no longer transmit 8 channels, only two.

The rest stays normal, AES output still send the signal to your speakers.
Also Totalmix keeps its functionality.

No worry, you can ad a ADI-2 to the UCXll for your external mastering compressor, no problem.

Hi Waedi! But that's sort of what I was afraid of, if I plug-in RCA to RCA that means I'm immediately down 6 channels for the mixing stage? Is there no situation in which I could make use of the whole 20 channels?

6 (edited by oli77sch 2024-03-25 11:04:37)

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

No, setting the so called 'ADAT' - what means the optical ports - to SPDIF, you have two further SPDIF channels instead of the eight ADAT channels. Both the XLR AES/EBU and the RCA SPDIF stay untouched from this!

So it is either

8 Optical ADAT +
2 RCA SPDIF +
2 XLR AES/EBU

or

2 Optical SPDIF +
2 RCA SPDIF +
2 XLR AES/EBU

Again, what you have in hardware on the UCX II is not replacing each other. You can use all of the three digital ports (optical + RCA + XLR) in parallel. There is no channel loss.
To my knowledge it’s indeed the case on other interfaces where you have to choose between optical or coaxial (RCA) SPDIF because there are only two SPDIF channels possible in total. But not on the UCX II!

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

7 (edited by fe.scolfaro 2024-03-25 11:08:35)

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

oli77sch wrote:

No, setting the so called 'ADAT' - what means the optical ports - to SPDIF, you have two further SPDIF channels instead of the eight ADAT channels. Both the XLR AES/EBU and the RCA SPDIF stay untouched from this!

8 Optical ADAT +
2 RCA SPDIF +
2 XLR AES/EBU

or

2 Optical SPDIF +
2 RCA SPDIF +
2 XLR AES/EBU

Ok that's great, thank you for the info smile You wrote this in a way more concise manner than the manuals, I guess them trying to explain a conversion of the RCA connections into a second set of XLR/AES messes everything up, and I still don't really understand what happens, according to what you wrote the Optical SPDIF and the converted RCA into AES would then become the same signal, but this is irrelevant if you do RCA to RCA. Did I interpret this correctly now?


This is the part that got me scratching my head:

RME wrote:

The SPDIF coaxial input accepts SPDIF and AES/EBU, Consumer as well as Professional format.
To receive signals in AES/EBU format, an
adapter cable is required.

Pins 2 and 3 of a fe-
male XLR plug are connected individually to
the two pins of a phono plug. The cable shield-
ing is connected to pin 1 of the XLR and the
ground contact of the phono plug.

The optical input automatically switches to SPDIF operation when such a signal is detected. The
audio information is then shown in TotalMix on the first two ADAT channels ADAT 1/2, which are
channels 13 and 14.

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

The coaxial / RCA, so called 'SPDIF' connection can also be used for AES protocol (using a corresponding cable with RCA plug on one side and XLR on the other.

And also the digital XLR, so called 'AES/EBU' can be used for SPDIF protocol.

So, in addition to my list above it could even be:

2 optical ('ADAT') SPDIF +
2 RCA ('SPDIF') SPDIF +
2 XLR ('AES/EBU') SPDIF =
6 SPDIF channels in total.

Of course in this case you would lose the eight ADAT and the two AES channels.

But also:
2 optical ('ADAT') SPDIF +
2 RCA ('SPDIF') AES/EBU +
2 XLR ('AES/EBU') AES/EBU

Or further mixes of the three connectors / connections.

One of the few downsides of the generally great written RME manuals is the fact, that for the digital connections some confusing synonyms are used:
'ADAT' is used instead of 'optical',
'AES/EBU' is used when the digital XLR connectors are meant.
But this is a general problem, names of digital audio protocols and hardware connectors are often mixed because there also are common uses…

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

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

… and yes:
The optical input automatically detects the incoming signal / protocol and switches to the right one.
Either eight channels ADAT or two channels SPDIF.
But this is absolutely independent of both the RCA SPDIF and XLR AES/EBU!

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

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

Oli THANK YOU, now I understand everything after almost two years of imagining a bunch of the digital connections were mutually exclusive big_smile RME people could definitely take a look at this conversation and do some updating of the manuals... In any case, now you've just shown me the most obvious path forward, 2/2 extra I/Os with greater dynamic range and less noise, combined to 8/4 analog I/Os and 8/8 optical.

That nets me 14 outs (2 mastering quality) and 18 ins (2 mastering), with 2 sets of monitors connected to the whole thing.

11 (edited by fe.scolfaro 2024-04-05 10:15:52)

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

Just an update, everything is hooked up!!

Had a brief half hour of confusion and reading the manual front to back (which is crazy for a device with only 5 buttons big_smile ) because I used color coded cables and didn't turn my brain on to the fact that one end had to have "wrong" colors to work... Very surprising that you'd even get a sync (only CONSUMER though) with SPDIF connected out to out and in to in xD

As soon as I turned my brain on (it was late and I had a long day of rack building and re-wiring), and flipped the cables on one end it just worked, as if the device had been made to be used in -exactly- that way (boss loopback!).

Now a question, why does conversion from my UCX 2 going through AES to the Neumann KH750 IMPROVE if the whole thing is clocked through SPDIF from the ADI-2 FS? I was under the assumption they had the same clock, but kick drums especially get noticeably "better", transients feel more defined altogether as if there's extra separation between transient and sustained material, and I'm not just talking about the loopback (which also improves in an obvious way), but audio playback in general.

12 (edited by ramses 2024-04-05 10:56:16)

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

fe.scolfaro wrote:

Just an update, everything is hooked up!!

Had a brief half hour of confusion and reading the manual front to back (which is crazy for a device with only 5 buttons big_smile ) because I used color coded cables and didn't turn my brain on to the fact that one end had to have "wrong" colors to work... Very surprising that you'd even get a sync (only CONSUMER though) with SPDIF connected out to out and in to in xD

As soon as I turned my brain on (it was late and I had a long day of rack building and re-wiring), and flipped the cables on one end it just worked, as if the device had been made to be used in -exactly- that way (boss loopback!).

Now a question, why does conversion from my UCX 2 going through AES to the Neumann KH750 IMPROVE if the whole thing is clocked through SPDIF from the ADI-2 FS? I was under the assumption they had the same clock, but kick drums especially get noticeably "better", transients feel more defined altogether as if there's extra separation between transient and sustained material, and I'm not just talking about the loopback (which also improves in an obvious way), but audio playback in general.

Sorry, but you are probably mistaken.
I could imagine that you have completely disregarded basic methodologies for comparisons here.

Just a few examples:

  • Rewiring and reconfiguring takes time, our brain can't remember such sound details for that long.

  • Such A/B comparisons must be made at the same volume level because louder always sounds better to our brain.

  • Then you should also use blind tests to rule out a certain expectation (brains "sadly" work with such a bias).

From a technical perspective, I think it is extremely unlikely that there will be any differences in sound (if you take the above-mentioned things into account and carry out valid tests), as

  • Both devices have FS clock and

  • use the same "SteadyClock FS" technology as clock "slave" for jitter attenuation.

  • Another point: you mention the Neumann is being connected through AES. So, no matter whether UCX II or ADI-2 FS are clock master or slave, the Neumann is always the slave to an FS clock, there is no difference.

Incidentally, for such discussions, I am missing something like a small drawing of the two cabling scenarios you are comparing here. With details of who is the clock master and where the active monitors are actually connected and how (analog or digital) so that it is clear where (D/A) conversions are taking place.

EDIT: Furthermore, a brief description about test methodology to exclude the above-mentioned errors which only lead to wrong and maybe also confusing results and discussions.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

ramses wrote:
fe.scolfaro wrote:

Just an update, everything is hooked up!!

Had a brief half hour of confusion and reading the manual front to back (which is crazy for a device with only 5 buttons big_smile ) because I used color coded cables and didn't turn my brain on to the fact that one end had to have "wrong" colors to work... Very surprising that you'd even get a sync (only CONSUMER though) with SPDIF connected out to out and in to in xD

As soon as I turned my brain on (it was late and I had a long day of rack building and re-wiring), and flipped the cables on one end it just worked, as if the device had been made to be used in -exactly- that way (boss loopback!).

Now a question, why does conversion from my UCX 2 going through AES to the Neumann KH750 IMPROVE if the whole thing is clocked through SPDIF from the ADI-2 FS? I was under the assumption they had the same clock, but kick drums especially get noticeably "better", transients feel more defined altogether as if there's extra separation between transient and sustained material, and I'm not just talking about the loopback (which also improves in an obvious way), but audio playback in general.

Sorry, but you are probably mistaken.
I could imagine that you have completely disregarded basic methodologies for comparisons here.

Just a few examples:

  • Rewiring and reconfiguring takes time, our brain can't remember such sound details for that long.

  • Such A/B comparisons must be made at the same volume level because louder always sounds better to our brain.

  • Then you should also use blind tests to rule out a certain expectation.

From a technical perspective, I think it is extremely unlikely that there will be any differences in sound (if you take the above-mentioned things into account and carry out valid tests), as

  • Both devices have FS clock and

  • use the same "SteadyClock FS" technology as clock "slave" for jitter attenuation.

  • Another point: you mention the Neumann is being connected through AES. So, no matter whether UCX II or ADI-2 FS are clock master or slave, the Neumann is always the slave to an FS clock, there is no difference.

Incidentally, for such discussions, I am missing something like a small drawing of the two cabling scenarios you are comparing here. With details of who is the clock master and where the active monitors are actually connected and how (analog or digital) so that it is clear where (D/A) conversions are taking place.

It is puzzling to me for sure, but I know how to make A/B tests and the one difference that was absolutely clear yesterday was with kick drums. Cabling is as follows:

Ucx 2 (AES) > KH750
ADI-2 FS (SPDIF) > Ucx 2
Motu 8pre-es (ADAT) > Ucx 2

The MOTU is always slave, and the adi-2 being master per SPDIF seems to improve transient definition. Maybe the fact that the KH750 is sharing a connection through the SPDIF Professional breakout has something to do with this (yes, the KH750 is doing D/A on my mains)?

14 (edited by ramses 2024-04-05 11:50:02)

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

Thanks, I bring this in a different order which is easier to see and remember for me

Option A - so the current scenario seems to be this

PC
|
UCX II---AES--------------------->AES---Neumann KH750---AN(L/R)---Satellites (Speaker)
||      \
||       \---ADAT------------------->ADAT---Motu 8 Pre es
||         \---ADAT<-----------------ADAT---/
||
|| SPDIF (coax)
||
ADI-2 FS (cm)<---->Compressor

cm=clock master


Option B - the other one with UCX II as clock master

PC
|
UCX II(cm)---AES----------------->AES---Neumann KH750---AN(L/R)---Satellites (Speaker)
||      \
||       \---ADAT------------------->ADAT---Motu 8 Pre es
||         \---ADAT<-----------------ADAT---/
||
|| SPDIF (coax)
||
ADI-2 FS <---->Compressor

To be honest, there is not much of a difference. Whether the UCX II sends out its clock signal or one as clock slave "purified" by its own SteadyClock FS circuit doesn't bring a significant change.
All is still based on jitter free FS clock technology:
- be it a clock signal from UCX as clock master with clock signal from its internal FS clock or
- a clock signal from ADI-2 FS, refreshed by UCX II (slave) and refreshed by SteadyClock FS technology.

Please consider that we had years ago already a discussion, whether there is a difference between ADI-2 Pro and ADI-2 Pro FS and the conclusion was that it most likely only a measurable difference if at all.

And here in this case you have even SteadyClock based tech in place, no matter whether ADI-2 FS or UCX II is the master.
The Neumann is always the client.

Now look at this RME video, how well the Jitter Suppression of SteadyClock FS works:
https://rme-audio.de/steadyclock-fs.html
https://www.youtube.com/watch?v=Ti0aHW-zYcs

Therefore, I have doubt that you can hear any difference (sorry).

But you are free to choose whatever you prefer.

Maybe only one tip, for operational reasons it would deliver to you more advantages to use the UCX II as clock master.
Because then you can determine the sample rate by the application, and the slaves can learn the clock from the master.
Or in other words, you have most likely only to select the sample rate in the DAW or in the Music Player and not additionally at the ADI-2 FS as clock master if the UCX II is the master.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14

Re: Fireface UCX 2 and ADI-2 FS (all digital I/Os used)

ramses wrote:

To be honest, there is not much of a difference. Whether the UCX II sends out its clock signal or one as clock slave "purified" by its own SteadyClock FS circuit doesn't bring a significant change.
All is still based on jitter free FS clock technology:
- be it a clock signal from UCX as clock master with clock signal from its internal FS clock or
- a clock signal from ADI-2 FS, refreshed by UCX II (slave) and refreshed by SteadyClock FS technology.

Please consider that we had years ago already a discussion, whether there is a difference between ADI-2 Pro and ADI-2 Pro FS and the conclusion was that it most likely only a measurable difference if at all.

And here in this case you have even SteadyClock based tech in place, no matter whether ADI-2 FS or UCX II is the master.
The Neumann is always the client.

Now look at this RME video, how well the Jitter Suppression of SteadyClock FS works:
https://rme-audio.de/steadyclock-fs.html
https://www.youtube.com/watch?v=Ti0aHW-zYcs

Therefore, I have doubt that you can hear any difference (sorry).

But you are free to choose whatever you prefer.

Maybe only one tip, for operational reasons it would deliver to you more advantages to use the UCX II as clock master.
Because then you can determine the sample rate by the application, and the slaves can learn the clock from the master.
Or in other words, you have most likely only to select the sample rate in the DAW or in the Music Player and not additionally at the ADI-2 FS as clock master if the UCX II is the master.

All valid points, especially that of automatically switching sample rates based on project settings. I'll use the setup for a while and see what makes more sense or what I get used to smile