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synchronization with rme ucx

Posted: Wed Oct 10, 2018 1:05 pm
by akoasma
Hey guys... I just bought my first audio interface with digital I/O - the RME UCX (next to a complete new audioworkstation yipiee :D ). So now I would like to record the Solaris via SPDIF and ask for advice. So here are my question (please excuse if they seem stupid but this digital-sync stuff is entirely new for me):

1. Is it enough to connect the Solaris SPDIF OUT via a Toslink cable with the SPDIF IN of the RME or do I have to establish a second connection (RME-OUT to Solaris-IN) to a have "2-way-connection"?

2. How do I decide if the Solaris or the RME should be Master respectively Slave? - advantages/disadvantages

3. The manual says that the Solaris runs on 48kHz as Master and on 96kHz as Slave (how do I actually switch between the two modes btw?)...
so I assume that I have to set the sample rate of the RME to the corresponding value depending on the chosen Master-Slave-Setting...
then I need to set the project-sample-rate of cubase also to the same value - right? - that could lead to projects running on a sample rate of 96kHz with Solaris being Slave for example (or 48 if Solaris is the Master)... is that right?

4. Cubase manual says if you have any digital INPUT you need to have a Word Clock conection between audio-hardware and external gear... Solaris has no Word clock...so SPDIF is enough?

5. And finally ... cubase needs to be set to external clock to detect tempo...

Thank you in advance for your advice on this :)

Re: synchronization with rme ucx

Posted: Wed Oct 10, 2018 4:18 pm
by minorguy
It's enough to just connect the SPDIF out of the Solaris to the SPDIF in of the RME. You don't need two way and you don't need word clock. But you probably need to set the RME SPDIF input to be 48KHz. The Solaris SPDIF can only output at 48KHz; there's nothing to set.
Note that MIDI clock is a different thing. If you want Cubase to sync to the tempo of the Solaris BPM tempo, you need to connect MIDI 5-pin or USB. Then set up Cubase to sync to external MIDI clock.

Re: synchronization with rme ucx

Posted: Wed Oct 10, 2018 5:24 pm
by John Bowen
akoasma wrote:
Wed Oct 10, 2018 1:05 pm
Hey guys...
3. The manual says that the Solaris runs on 48kHz as Master and on 96kHz as Slave ...
Unfortunately, the manual is not correct on this. Originally I though it was the case, so I communicated this to Brent. The chip that handles the SPDIF will only output at 48 kHz - if it receives a clock running at 96 kHz, it will convert to 48k. That is what I had misunderstood.

John B.

Re: synchronization with rme ucx

Posted: Thu Oct 11, 2018 9:39 am
by akoasma
Thank you for your answers. What I think I have understood so far is that there are actually 2 independent synchronisation-processes involved which do not interfere with each other at all. The first is the "musical" synchronisation of my outboard gear to the beat-grit of cubase. This will stay as it used to be - accomplished via MIDI/USB connection and cubase being the "master" - so clock source in the settings remains internal. The second synchronisation only refers to the digital audiostream from the Solaris to the RME interface. The samplerate here is determined by the Solaris (48kHz). This is the samplerate throughout the whole system (including cubases project samplerate). But what is still not clear to me is the master/slave question concerning Solaris/RME. John wrote the Solaris would convert incoming clock if it differs from 48kHz - so the Solaris can be the slave (and will be if I set the RME in it`s settings to master?)...
Does the solaris also send clocksignal or only audio?
Is the samplerate the clocksignal?
Is there a default-state of the solaris concerning being a master or a slave?... can I freely choose ? does it matter at all or can it lead to further consequences...like: When the solaris would be master but not constantly streaming then RME switches to master (quite fast I think - but I heard it can still lead to dropouts or artefacts or whatever)
I have also read that when it comes to digitalaudiosyncstuff the errors might not be apparent during production and mixing but can become a problem in the mastering process - that is actually the reason why I`m inquiring so much ... because I really want to avoid that of course.

Thanks again :-)

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 9:19 am
by akoasma
OK maybe that were too many (and not so smart) questions... so I will try one more time and boil it down to the following:

The Solaris has an opt.-IN, so he is able to receive clock-signal and therefore has the potential to operate as a Slave but this functionality is not (yet?) implemented in the OS - is that correct?

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 9:30 am
by John Bowen
I believe it’s implemented. Best to ask those on the forum who are using the SPDIF In/Out what they are doing.

Anyone?

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 11:40 am
by minorguy
I don't think the terminology of master/slave is so appropriate with SPDIF. SPDIF has the clock embedded along with the audio signal. The sender sends at the frequency it wants to and it's up to the receiver to listen at that frequency. The receiver cannot specify a clock. Usually you just set both sides to the same frequency and plug it in and that's it, away you go. It's almost as easy as audio cables.
Whether the Solaris SPDIF can accept an input at 96KHz...I don't think I ever tried that. John says above that he understood it can. But why not just try it? I don't have the time at the moment to try it. (Actually, whether it's possible with SPDIF to auto-detect input frequency I'm not sure. But either it will work or it won't. Just try it.)

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 4:50 pm
by John Bowen
Yes, I do not have a SPDIF connection to try here.

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 5:49 pm
by minorguy
Sorry, when I said to just try it I meant akoasma. :D

Re: synchronization with rme ucx

Posted: Fri Oct 12, 2018 5:53 pm
by John Bowen
Right - I got that... :-)

Re: synchronization with rme ucx

Posted: Sun Oct 14, 2018 8:21 pm
by akoasma
Hello :-)... yes I will try... I just have to finish a project on my old system and while planing the new one I came across these questions... thanks for your kind responses and support :-)