Kemper SPDIF into Focusrite Scarlett

  • Hello all, I am using a Focusrite Scarlett 18i8 as a standalone "mixer" to combine my Kemper toaster, Trio+ looper, music player etc to output to some studio monitors. The Kemper is connected through SPDIF; now I understand the Kemper has to be the master for the digital signal so I set the Focusrite to get the sync source / clock from SPDIF. My problem is, when the Kemper isn't on, I get no signal output from the interface. I don't have a computer hooked up to the interface normally, and you can't change the sync source without one. But I sometimes just want to listen to music through an analog input.
    I guess I'm stuck with having to turn on the Kemper any time I want to use the interface but has anyone else experienced this? I think I may just go back to using the Kemper Main Outs into the interface analog inputs, at least I have the flexibility then...

  • That shouldn't be a problem. If you set another source (music input) in Mix Control to blend in with the Kemper mix on SPDIF it will be present whether the KPA is on or not. The Scarlett remembers the last settings left in Mix Control. Just fade out your music input on the actual Scarlett until such time as you want it blended in the mix.

  • That's what I expected but not what's actually happening - I have the Trio plugged into line inputs 5&6, iPhone into 7&8 for music, Kemper into SPDIF. In MixControl, Mix 1 is inputs 3-8 and SPDIF all directly sent to the main outputs 1-2 and headphones. When the Kemper is off, I get no sound from the Scarlett at all. As soon as I turn the Kemper on, part-way through its boot-up process, everything then comes out the monitors. When I turn the Kemper off, I lose all sound again.
    I have a ticket in with Focusrite but it may be a while... just wondered if anyone else gets this, it seems a fairly popular interface.

  • Test by having the KPA on and also music playing out the iPhone into 7&8. In MixControl slide the fader down for SPDIF and you should still hear the music playing but no sound from your guitar. Bring SPDIF fader back up and turn down the faders for 7&8 and you should have guitar and no music. Same thing working the hardware fader knobs on the Scarlett. Seems your routing 7&8 through SPDIF, therefore no sound when KPA is turned off.

  • I had a response back from Focusrite - sadly, when the clock source is set to SPDIF, the analog inputs will not work if the SPDIF device is not connected & on. As I don't have the interface & Kemper near my computer normally, I can't adjust the clock source whenever I want to - and it's a gen 1 model so no way to do it from iPad either. That's a shame, I will have to go back to using the analog main Outs from Kemper into the Scarlett for now.
    On a related note, I have a bunch of "nice" SPDIF cables of various lengths; none of them will fit the Kemper because of the way the socket is recessed in the body!!
    Thanks for your help Zapman

  • I created a thread requesting this a few months ago so we could get a definitive answer once and for all.

    Bad news, I'm afraid. Christoph Kemper himself said it's not possible due to "hardware restrictions" and even apologised for this, proving he's a class act IMHO:

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

  • Yeah, same here. Got a MOTU 828x, and their driver updates for mac are somewhat iffy lately. I get regular MacOS warnings about 64bit support. But at MOTU they just say: "not to worry, we'll release a compatible driver in time for the next release of MacOS".

  • The warnings are standard fare as they're a part of Apple's "programme" to make sure everyone's forewarned about the drop of 32-bit support, which IIRC will take place in OS 10.15, probably around August / September next year.

    The warnings therefore don't make anything "iffy" (the implication in your post), be they for an application, plugin, drivers or whatever.


    IIRC I had to dismiss such warnings in 2017 on my MBP running High Sierra when installing the MOTU driver for an 828 MkIII interface, so the Apple started them "early". An option in Sys Prefs to disable these pop-ups would've been handy IMHO, but alas, all we can do is ignore them for now.

  • Hi Monkey_Man,

    to be fair, my unit is still working reasonably stable. And overall I'm quite happy with the MOTU hardware. With iffy I meant:

    • last driver update was july 2017, since we've had 2 major OS releases and pinned messages on about OS compatibility, but no new driver.
    • since High Sierra, I get occasional driver crashes with a loud pop / hanging squeel. Suggested workarounds on have not been helpful so far.
    • Motu audio setup software has been crashing quite regularly.
    • CueMix less frequently crashes but also hangs or is not responding to a freshly booted 828
    • Thunderbolt connection crashes bootcamp (latest windows driver is from 2015)
    • When switching from bootcamp to macos and back audio levels are all messed up

    Above problems are an inconvenience mostly and I didn't loose any recordings, but I'm anxious about outdated drivers, messages from Apple's 64bit "programme", and reluctant to update my OS.

    Regarding Kemper, on of the problems of Motu Audio setup regularly crashing is that switching the clock source sometimes crashes my audio system completely. I usually set my 828x as a SPDIF clock slave of the Kemper for recording sessions (which works well). Then when I switch back and select Internal as a clock source again sometimes my system freezes. This is new since High Sierra upwards. I was hoping to circumvent this issue by setting the Kemper as slave, but alas, as I found out in this thread, this cannot be done.

  • Sorry to hear about the "anomalous shenanigans", man. Bummer. :pinch:

    As for driver updates, MOTU has always been in communication with Apple and historically it's been the first company to release new drivers with every integer-OS update. Only once, about 15 years ago, a freshly-released driver caused issues, and an updated one was dropped 2 or 3 days later. The old hands at MOTUNation will remember it 'cause it was a rare, anomalous event if ever there was one.

    I can't speak for Windows, but MOTU's M.O. is to not provide updated drivers unless they're necessary (duh), meaning that no matter how many OS's you go through, and no matter how-old it is, the most-recent driver will work. That said, back in the day it was important to run certain chipsets when using Windows and running MOTU hardware. Since the company made Digital Performer available to Windows (roughly 4 or 5 years ago), I've developed the sense that things have improved on that front, but who knows, there could be a compatibility issue with a hardware component you're running. If it's an off-the-shelf Mac running Bootcamp, I doubt it'd be hardware-related, but I'd be suspicious of running a pro-audio system in a Windows emulation. You'll probably tell me that heaps of people do it, but call me old-school; it just doesn't feel right to me.

    Curious: Are most of these issues cropping up under Windows or Mac OS? If the former, would it be possible to run your "important" (music-creation) apps and the interface for serious work when booted into OSX?

  • Hi, found this old thread and thought to ask

    Im planning to buy Focusrite Scarlett 8i6 3rd gen for same use as OP. Hoping to use KPA via SPDIF and use 8i6 as standalone mixer for different sources. Am I going to get same trouble with sync clock setting. My KPA is older version so as i understood it cannot handle slave clock setting, right?

    Does anyone know is same issue also with 3rd gen Scarlett as 1st gen?

  • Sorry, I don't know about the 3rd gen models, perhaps Focusrite have changed the internals to fix this. If you haven't bought yet, I'd suggest sending them a question about it from their website (Support->Contact Support), keep the question simple and they should get back to you. It's a holiday weekend here in the UK so I don't think they will answer before Tuesday though...

  • Well, i asked this from Focusrite support and they answered :

    "You shouldn't have any problem using an 8i6 as a stand-alone mixer. you will however have to connect it to a computer of some description to configure it to work as you wish. Yes, the 8i6 clock source will have to be set to S/PDIF which is also done in Focusrite Control, unfortunately you'll have to change it back to Internal if the Kemper isn't connected or the 8i6 will be waiting for the clock from the digital input and the ADC and DACs won't be active. "

    This makes me thinking is it worth upgrading from 2i2 2ndgen - > 8i6 3rd gen. Biggest problem at this time is plugging/unplugging cables and adjusting gain levels every time i switch playing thru kemper, vst plugins, and different sources and if i have to switch cables and setting even with 8i6 also

    One good thing would be that i could reamp easier with Kemper when needed, even it need different settings and also i could connect kemper to line inputs and guitar to xlr mic input to play with plugins

  • So, I think you will have the same problem with the gen3 model as with earlier ones - if you set the SPDIF on the interface to work with the Kemper (ie set to external clock) then when the Kemper is not connected or not powered on, the interface will not pass through any sound - so it will only work as a mixer if the Kemper is on. To change the SPDIF setting, you need to connect USB to a computer and open the Focusrite Control software to switch it to internal SPDIF. If that isn't a problem for you, then great. Otherwise, yes, you could connect the Kemper to the line inputs on the back, you will still have 2 other line inputs and the 2 front inputs available. When/if you want to re-amp, then you can use SPDIF & switch the interface to external for that session.

    I don't know if all interfaces work like this ... ?