[Solved] Slave to Audio Clock (S/PDIF)

    I wonder if someone in the team would be able to let us know whether or not this will be possible one day.


    Is it simply a matter of coding or is there a hardware impediment that prevents this possibility?


    Optional reading ~ My reason for needing to know:
    I've a long-term lay-buy for a MOTU AVB system that's near the point at which I'll be expected to make the purchase. Just last week I realised that one of the interfaces (the 16A) could be changed (I'd be sacrificing a number of analogue inputs, hence the question that follows' importance to me) for the 1248, which has RCA S/PDIF I/O with SRC. The 16A that I've had ordered all along doesn't have this and I'd decided long ago to just use its analogue I/O for recording and reamping. The SRC in the 1248 would allow me to record the Kemper's S/PDIF output 'though without having to slave the AVB system to it, which would be wonderful, but there's a problem: In order to send a recorded DI track back to the KPA, I'd have to set the MOTU gear to slave to it 'cause the Kemper won't interpret an incoming clock signal. All well-and-good, but unfortunately there's no setting or ability of the MOTU to automatically revert back to internal clocking when I power the KPA down.


    Someone here told me a month ago that most interfaces allow you to set, say, S/PDIF as the source, and then whenever it's absent, they'll automatically switch to "internal" and then back again any time the S/PDIF source becomes active again. Not so with the MOTU AVB system, unfortunately, and I don't want to have to mess with the web app before and after every time I choose to reamp, which with any luck will happen a lot.


    If the KPA could slave to clock it'd be a case of "problem solved".


    Thank you in advance for any insight shared; this is ultra-important to me 'cause returns and swaps won't be possible once I plunk down the dough, so to speak.

    The MOTU has automatic, built-in SRC, AJ. You can feed it any sample rate without even clocking it to the source, and it'll allow you to record. Fantastic feature, this, so no need for a convertor.


    The problem arises, as I said, when one needs to go to the Kemper, not come from it. It defeats the purpose if the KPA can't clock to it.


    Yeah, worst-case scenario would be having to switch to the network app to change clock sources on the MOTU whenever the KPA's being used, but even this "little" thing would be a vibe killer (or at least a contributor) for me. External sync on the Kemper is the obvious, keep-it-as-simple-as-possible, non-flow-breaking solution AFAIA, hence my question. Changing my primary-interface model becomes a less-attractive prospect given that the analogue route using the 16A didn't require jumping through any hoops. If I were to go S/PDIF instead, it wouldn't be at the expense of workflow, at least not ideally.


    I asked because I've not seen (not to say it hasn't been issued) a definitive statement from Kemper that it can't be done. My gut tells me that it can be, and that the fully-functioning S/PDIF I/O ports and the ability to add code (OS tweak) should in theory be all that's required... and a little programming from the boffins at Kemper, but nevertheless, I'm seeking clarification.


    Thank you for your input and interest, brother.

    You can do this with the Apollo Spdif as well. With the Apollo, if there's no SPDIF to sync to, it defaults to the internal clock. Wondering why that's not possible with the Motu. I'm sure it is, or you've overlooked something.

    Yeah bud, that's what I've been thinking, so I asked in the mega-MOTU-AVB thread over at BeerGutz and was told that it wouldn't behave that way.


    As I said in the OP, I was told here not long ago that most interfaces behave this way, and yet the manual and GS have yielded nought in the way of a solution or answer to this basic question. Well, I was told by someone (can't remember where now) that the interface would remain in "seeking sync" mode - you know - lights flashing whilst it awaits a signal - rather than "give up" after a few seconds and revert to internal. I don't get it either, mate; what I've just described would be the logical way for it to behave IMHO, so who knows?


    In the meantime, the KPA's being able to sync to an external clock source would solve this once and for all, and do so for every S/PDIF-capable interface on the planet.

    +1


    My cheap little Focusrute Saffire Pro14 doesn't automatically switch to internal sync if there is no SPDIF connected. So I have to remember to keep switching back and forth in Saffire mix control. I often find myself listening to clicks and pops because I'm not synced to SPDIF. On the other hand, I once thought my whole system was down because nothing was coming through my monitors. It turned out that I had left the setting at SPDIF and the Kemper wasn't switched on.

    Great to know that it's not just the MOTUs, Alan. Thank you for that, mate.


    The solution for both of us, then, would be the Kemper's being able to sync from an external source.


    Hoping someone on the inside can answer the question of the thread - is it possible to programme the OS to do this or is there a hardware limitation that prevents it entirely?

    Quote from Monkey_Man

    Hmm... food for thought; thank you Arne.


    Experience here suggests 'though that if there's no answer, it's possible, given that if it'll never be possible the team would know it'd be safe to say so 'cause its "word" could not be broken.

    Oh man Nicky, that's a hell of a rabbit-hole to jump into. I had to re-read that about 5-6 times (it's the beer). I definitely understand and agree with what you're saying...and you think just how I do, hahaha.

    Disclaimer: When I post demo clips for profiles, there will be some minimal post-processing, unless stated otherwise. I normally double-track hard L/R, and add to the main buss a small amount of EQ and a limiter/comp set pretty light as well. Sometimes I get test profiles in advance of release, though 90% of my clips will be from packs I have purchased.

    Like 1

    Haha, that is exactly what I mean. Of course. :D

    Disclaimer: When I post demo clips for profiles, there will be some minimal post-processing, unless stated otherwise. I normally double-track hard L/R, and add to the main buss a small amount of EQ and a limiter/comp set pretty light as well. Sometimes I get test profiles in advance of release, though 90% of my clips will be from packs I have purchased.

    Like 1
    Quote from ckemper

    The Profiler cannot be slaved due to hardware restrictions.
    Sorry about that!

    That's a bummer for some, but it's so nice to get straight answers like this, especially when you know it won't be the answer everyone wants to hear.


    Thank you. :)

    Disclaimer: When I post demo clips for profiles, there will be some minimal post-processing, unless stated otherwise. I normally double-track hard L/R, and add to the main buss a small amount of EQ and a limiter/comp set pretty light as well. Sometimes I get test profiles in advance of release, though 90% of my clips will be from packs I have purchased.

    Like 2

    Yes, not nice, as it makes the SPDIF option almost unusable, as there is not too many interfaces with needed options. BTW never understood why the Kemper did not get a USB port with digital out option .........