• Registered: 2024-04-16
  • Posts: 8

Topic: RME Digiface USB Toslink output channel

I'm a new user of Digiface USB and use it as multiple toslink output device.
When it works as toslink output it's a bit inconvenient because I need to route the channel again when using different sampling rate due to the channel change.

For 44.1/48kHz sampling rate I'll need to use ADAT 1/2 for toslink out 1, ADAT 9/10 for toslink 2 and so on.
But for 88.2/96kHz it'll become ADAT 1/2 for 1st output, ADAT5/6 for 2nd output, ADAT 9/10 for 3rd output
And 176.4/192kHz would be ADAT 1/2 for 1st output, ADAT 3/4 for 2nd output.

This kind of order change makes the device hard to use at different sampling rate.
Is it possible to set SPDIF out for ADAT 1/2, 3/4, 5/6, 7/8 and map it to 1st, 2nd, 3rd, and 4th toslink output no matter what sampling rate I'm using?

Thank you very much.

  • waedi
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Re: RME Digiface USB Toslink output channel

Sorry, no, this is fix, no remapping possible.
Each toslink port can be a SPDIF output, always use the first two channels of the 8 Adat channels.
You have to adapt in Totalmix for this.

M1-Sonoma, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2024-04-16
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Re: RME Digiface USB Toslink output channel

Thanks for the reply...I guess the different sampling rate isn't a thing for other users...

4 Reply by MC

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Re: RME Digiface USB Toslink output channel

This is actually really easy - barely an inconvenience.

You need to route Software Playback 1/2 to Hardware Output channels 1/2, 3/4, 5/6, 7/8, 9/10, 13/14, 17/18 and 25/26. If done then no matter the sample rate all four SPDIF outputs will send out Software Playback 1/2.

Regards
Matthias Carstens
RME

MC's Website

5 Reply by ramses (edited by ramses 2024-04-17 08:56:25)

  • ramses
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Re: RME Digiface USB Toslink output channel

yys310 wrote:

Thanks for the reply...I guess the different sampling rate isn't a thing for other users...

Higher sample rates require more bandwidth; 2 of the 8 ADAT channels are used for double speed and 4 for quad speed.

With your 4 ADAT ports, this means for ADAT protocol:
- single speed: 4x8=32 channels, ADAT1-8, 9-16, 17-24, 25-32
- double speed: 4x4=16 channels, ADAT1-4, 5-8, 9-12, 13-16
- quad speed: 4x2=8 channels, ADAT1-2, 3-4, 5-6, 7-8

When switching to SPDIF only the first two channels of an ADAT port can be used
because SPDIF protocol by definition supports 2 channels, regardless of the sample rate being used:
- single speed: ADAT1/2, 9/10, 17/18, 25/26
- double speed: ADAT1/2, 5/6, 9/10, 13/14
- quad speed: ADAT1/2, 3/4, 5/6, 7/8

An easy solution to cover sample rate changes for SPDIF has been posted by MC a few minutes ago in previous post (#4).
Otherwise, for ADAT, you have to provide the routing as needed because the number of channels changes with single, double, quad speed.

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

6 Reply by yys310 (edited by yys310 2024-04-17 13:02:23)

  • Registered: 2024-04-16
  • Posts: 8

Re: RME Digiface USB Toslink output channel

MC wrote:

This is actually really easy - barely an inconvenience.

You need to route Software Playback 1/2 to Hardware Output channels 1/2, 3/4, 5/6, 7/8, 9/10, 13/14, 17/18 and 25/26. If done then no matter the sample rate all four SPDIF outputs will send out Software Playback 1/2.

Thank you for the suggestion.
My playback content are different for the 4 SPDIF output so I cannot directly map the channel like this.
But this does provide a very good way to route it. Thanks!
For SPDIF A: 1/2 for 48, 96,192 would all be 1/2
For SPDIF B: 5/6 for 96 and 192 ; 17/18 for 48
For SPDIF C: 9/10 for 48 and 96 ; 3/4 for 192
For SPDIF D: 25/26 for 48, 13/14 for 96 and 7/8 for 192
That'll route all data to corresponding output no matter which sampling rate I'm using.

Thanks so much for the help!

  • Registered: 2016-06-14
  • Posts: 1,121

Re: RME Digiface USB Toslink output channel

Following this thread out of pure interest.
yys310, I don’t understand what protocol do you use? Is it ADAT or SPDIF?

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2
  • Registered: 2024-04-16
  • Posts: 8

Re: RME Digiface USB Toslink output channel

oli77sch wrote:

Following this thread out of pure interest.
yys310, I don’t understand what protocol do you use? Is it ADAT or SPDIF?

SPDIF

  • Registered: 2016-06-14
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Re: RME Digiface USB Toslink output channel

yys310 wrote:
oli77sch wrote:

Following this thread out of pure interest.
yys310, I don’t understand what protocol do you use? Is it ADAT or SPDIF?

SPDIF

But then you have a maximum of eight output channels in total anyway, two per each toslink port, regardless to the sample rate!

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2
  • Registered: 2024-04-16
  • Posts: 8

Re: RME Digiface USB Toslink output channel

oli77sch wrote:
yys310 wrote:
oli77sch wrote:

Following this thread out of pure interest.
yys310, I don’t understand what protocol do you use? Is it ADAT or SPDIF?

SPDIF

But then you have a maximum of eight output channels in total anyway, two per each toslink port, regardless to the sample rate!

Yes, the problem is I need to route to 1/2, 9/10, 17/18, 25/26 for 44.1/48 kHz;
1/2, 5/6, 9/10, 13/14 for 88.2/96 kHz and
1/2 3/4 5/6 7/8 for 176.4/192 kHz sampling rate.

So my original question is asking how to solve this problem.
My previous reply should work but I haven't test it yet. That should solve my problem.

  • Registered: 2016-06-14
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Re: RME Digiface USB Toslink output channel

I do have a Digiface USB myself, but I can’t check it at the moment because I’m not at home: how do software playback and hardware output channels in Totalmix behave when switching from ADAT to SPDIF?  Are there still all of the 32 channels visible (at 44.1 or 48 kHz)?

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2
  • Registered: 2024-04-16
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Re: RME Digiface USB Toslink output channel

oli77sch wrote:

I do have a Digiface USB myself, but I can’t check it at the moment because I’m not at home: how do software playback and hardware output channels in Totalmix behave when switching from ADAT to SPDIF?  Are there still all of the 32 channels visible (at 44.1 or 48 kHz)?

Yes they are.
I'm using ASIO output so I'll see 32+2 ch output @ 44.1/48; 16+2 @ 88.2/96 and 8+2 @ 176.4/192 kHz sampling rate.

  • Registered: 2016-06-14
  • Posts: 1,121

Re: RME Digiface USB Toslink output channel

I see…
So your idea in post 6 (after MC's suggestion) is surely the best solution.

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2
  • Registered: 2022-03-22
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Re: RME Digiface USB Toslink output channel

Snapshots are very handy.

15 Reply by MC

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Re: RME Digiface USB Toslink output channel

Yes, loading different routings for the three sample rate ranges would be easy too.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2024-04-16
  • Posts: 8

Re: RME Digiface USB Toslink output channel

yys310 wrote:
MC wrote:

This is actually really easy - barely an inconvenience.

You need to route Software Playback 1/2 to Hardware Output channels 1/2, 3/4, 5/6, 7/8, 9/10, 13/14, 17/18 and 25/26. If done then no matter the sample rate all four SPDIF outputs will send out Software Playback 1/2.

Thank you for the suggestion.
My playback content are different for the 4 SPDIF output so I cannot directly map the channel like this.
But this does provide a very good way to route it. Thanks!
For SPDIF A: 1/2 for 48, 96,192 would all be 1/2
For SPDIF B: 5/6 for 96 and 192 ; 17/18 for 48
For SPDIF C: 9/10 for 48 and 96 ; 3/4 for 192
For SPDIF D: 25/26 for 48, 13/14 for 96 and 7/8 for 192
That'll route all data to corresponding output no matter which sampling rate I'm using.

Thanks so much for the help!

Oh...what am I thinking...
It's impossible to route all signal to the desired SPDIF output since it'll change the order as sampling rate change...
the ADAT 5/6 would be 2nd SPDIF out for 88.2/96 and 3rd SPDIF out for 176.4/192
So it's impossible not reroute the output...
Save different routing for different sampling rate is the only solution...

  • Registered: 2024-04-16
  • Posts: 8

Re: RME Digiface USB Toslink output channel

waedi wrote:

No, the Adat 5/6 wil not be a SPDIF, always the first two channels of an Adat-8-channel-package will turn into an SPDIF channel.
Channels 1/2 will be the SPDIF on the toslink port 1
Channels 9/10 will be the SPDIF on the toslink port 2
Channels 17/18 will be the SPDIF on the toslink port 3
Channels 25/26 will be the SPDIF on the toslink port 4
Send your signals to those channels, switch all Adat ports to SPDIF, then you can switch sample rates and all signals will stay at the output.

NOT when you're running at 176.4/192kHz sampling rate.

  • Registered: 2020-11-09
  • Posts: 6

Re: RME Digiface USB Toslink output channel

MC wrote:

Yes, loading different routings for the three sample rate ranges would be easy too.

If the user intends to use the Digiface as “default” audio interface for audio reproduction, he will need to change routing every time the music changes sample rate. Which is impractical- only practical way would be to keep sample rate constant at the source (eg resample anything different from the default).

This use case is common if someone wants to use the Digiface to drive 2+ DACs via SPDIF, eg for a multichannel setup or for an active crossover scenario.

FWIW, keeping sample rate constant would ensure consistency in the delay between different dacs (which is affected by sample rate).


Problem would be solved if the Digiface I/o in SPDIF mode were driven as “physical SPDIF” (always 2 channels) regardless of the sample rate.

  • Registered: 2016-06-14
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Re: RME Digiface USB Toslink output channel

HerbertWest wrote:

Problem would be solved if the Digiface I/o in SPDIF mode were driven as “physical SPDIF” (always 2 channels) regardless of the sample rate.

Maybe I get you wrong. But to my understanding that would be incredibly confusing regarding the channel numbers. As it is now, the four optical output ports can be switched individually between ADAT and SPDIF. There is no overall SPDIF mode. So when I switch only the second port to SPDIF for example, the ADAT channels on port 3 stay nr. 17-24 and on port 4 nr. 25-32 at single speed.

UCX - FF 400 - Babyface pro - Digiface USB - ADI-2 (original)
Mac mini M1 - Macbook pro - iPad Air2
  • Registered: 2020-11-09
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Re: RME Digiface USB Toslink output channel

oli77sch wrote:
HerbertWest wrote:

Problem would be solved if the Digiface I/o in SPDIF mode were driven as “physical SPDIF” (always 2 channels) regardless of the sample rate.

Maybe I get you wrong. But to my understanding that would be incredibly confusing regarding the channel numbers. As it is now, the four optical output ports can be switched individually between ADAT and SPDIF. There is no overall SPDIF mode. So when I switch only the second port to SPDIF for example, the ADAT channels on port 3 stay nr. 17-24 and on port 4 nr. 25-32 at single speed.

Totally - I am not advocating for this, either. I was just trying to explain the rather unusual use case: Digiface used to drive 4x SPDIF dacs.

FWIW, when people think about using a convolver and the above 4x dacs, they might consider that the convolver itself lags/clicks when switching sample rate. To avoid that, I decided to keep playback at 48khz and resample anything. This also indirectly solves any problem with channel routing.
[I have abandoned that setup to a much simpler UCX2+Adi combo, so I can run bass management by A/D the output of a 5.4.1 AVP]

  • Registered: 2020-12-24
  • Posts: 18

Re: RME Digiface USB Toslink output channel

HerbertWest wrote:

Totally - I am not advocating for this, either. I was just trying to explain the rather unusual use case: Digiface used to drive 4x SPDIF dacs.

I'm not sure how unusual this use case is anymore. At least, that is exactly what I am trying to do :-)

As more and more devices in our audio chain (home office / home stereo) become digital, many of us would love to use a Digiface USB or similar products to integrate between our range of S/PDIF source devices and our S/PDIF playback devices (e.g., DACs, Active Speakers, Headphone Amps). In such use case, ADAT is never in scope.

Of course, I'm also part of the cross-over market who has grown to love our RME-based product(s); but I also know that my use case is outside of RME's core focus.

  • Registered: 2020-11-09
  • Posts: 6

Re: RME Digiface USB Toslink output channel

rcstevensonaz wrote:
HerbertWest wrote:

Totally - I am not advocating for this, either. I was just trying to explain the rather unusual use case: Digiface used to drive 4x SPDIF dacs.

I'm not sure how unusual this use case is anymore. At least, that is exactly what I am trying to do :-)

True, but also consider that all dacs will have a slightly different latency as sample rate changes, especially if using different models or vendors. Will your active crossovers still be perfectly aligned as that happens?

In the end, because of that and of convolver lag, I keep sample rate constant at the source (eg I resample in roon), and feed mains+subs from the same 4 channel dac (adi2 pro) smile anyway, just my 2c.

23 Reply by rcstevensonaz (edited by rcstevensonaz 2024-05-28 23:40:21)

  • Registered: 2020-12-24
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Re: RME Digiface USB Toslink output channel

HerbertWest wrote:

True, but also consider that all dacs will have a slightly different latency as sample rate changes, especially if using different models or vendors.

Obviously that situation varies by context, and is a very important factor in your case where precise clock synchronization is critical for coherence.

But it becomes irrelevant in the context when the input streams and output streams are fully autonomous.

In my case, I have several input sources that I want to have always active, and thus I want to mix these autonomous streams together in the digital realm (rather than via an analog mixer). For example: home PC, WiiM Pro network streamer, CD/DVD, and a turntable (Waxwing). I don't care one bit whether the "phone ringing" from my PC alerting me that I have an incoming Teams call is even remotely synchronized with the song Roundabout by Yes that is currently playing on my WiiM Pro.

Likewise I don't care if the DSP'ed output going to my headphone DAC/amp next to my comfy chair is precisely synchronized with the DSP'ed output being routed to the active speakers sitting on my work desk. What I do want is the matrix mixing & routing flexibility so that I can easily switch from sitting in my comfy chair to jumping onto a work call in seconds without having to do anything other than pausing the WiiM Pro. (And then after the call is done, I just resume playing the WiiM Pro to continue listening to Roundabout at my desk as I work on the tasks that came out of the call.)

Again, this is only to highlight how the power of Digiface USB's mixing & routing could potentially be used in an environment that is all S/PDIF input and output devices, with no need for ADAT at all (and not even any need for time-alignment between the autonomous audio streams).

  • Kubrak
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Re: RME Digiface USB Toslink output channel

Just one note. Digiface USB does not remember its routing if switched off. It is not designed for standalone work.

So one has to have either PC on to load routing to DF, or keep DF powered on all the time (using e.g. powered USB hub) so that it remembers routing from PC.

  • Registered: 2024-06-01
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Re: RME Digiface USB Toslink output channel

Kubrak wrote:

Just one note. Digiface USB does not remember its routing if switched off. It is not designed for standalone work.

So one has to have either PC on to load routing to DF, or keep DF powered on all the time (using e.g. powered USB hub) so that it remembers routing from PC.

Oh, that’s interesting, thanks. I hadn’t noticed anything wrong while power-cycling (unplugging) the DigiFace a few times earlier today, but during all that TotalMix was running and likely took care of the routing setup.