How important is S/PDIF on new audio interface?

  • With a decent interface like RME, there is no need to change clocking settings. You simply set your preferred clock source to SPDIF. If the KPA is turned off it automatically changes to internal clock master and also passes this clocking to my digital mixer which is connected via ADAT. So it works in any scenario.

    That sounds dandy, Till!


    Say, if you turn the KPA back on does the interface then automatically derive it's clock from there, and so on?

  • As I've said elsewhere, if you set your guitar-input level correctly on the KPA and record and play that back to it at unity gain, you'll never have to think about levels. The signal-to-noise ratio is irrelevant with any decent modern interface, as I also said. I'm speaking specifically about DI and reamping, 'cause that involves more than just the route into the computer and is therefore the "ultimate" test of the efficacy of the analogue method.

    Doesn't this depend on the profile that you choose? For instance, I would always set my gain on my inteface higher or lower on high or low level gain profiles. The gain would even change on various profiles from the same author (Bert Meulendijk), which are fairly well balanced volume wise.



    Does S/PDIF completely eliminate this problem?

  • Great question, mate! I was talking specifically about DI and reamping, as I said, but seeing as you asked...


    If you've set your output settings on the KPA correctly (using the "pad" to attenuate the overall level leaving the KPA), you can create a "gain range" that you'll operate within. That way, even if you're using a loud rig, you should be OK.


    This gets back to the latest thing I seem to be banging on about here, which is that we ought to record at much-lower levels. Clipping, inter-sample peaks and suffocated (smaller, "narrowed") mixes begone!


    If your loudest Rigs hit, say, -12 or 15dB, your quieter ones will obviously be OK too. I wouldn't worry about it if they're 10dB down on the loudest ones. If they were 20dB or more down I'd certainly crank them into the -18dB area, but this is unlikely or you'd have barely been able to hear them on the KPA in the first place and would have levelled them somewhat.


    Does S/PDIF completely eliminate this problem?

    No, it doesn't. You still have to set sensible record levels IMHO, as mentioned above.


    If you haven't tried it before, try the -15 -> -18dB area. Lots of headroom for anomalous nasties, and your mixing will thank you.

  • Definitely not a "must" for this particular use, but why not have it in case it comes up later? I've owned cheap interfaces before and found they're really more expensive in the long run. I've owned RME products for years, and downsized to an RME BabyFace Pro after I didn't need all the inputs. Really great quality.
    I also own a Presonus Studio 68 for my iPad, and it comes close to the RME as far as sound. IMHO, worth looking in to.

    Excuse me crashing your thread. I have an RME Babyface Pro and am getting some crackling. I've used regular SPDIF cable and used a powered converter to Optical cable...is this how you do it @audiomitch ? Do you get artifacts at all? Many thanks

  • Excuse me crashing your thread. I have an RME Babyface Pro and am getting some crackling. I've used regular SPDIF cable and used a powered converter to Optical cable...is this how you do it audiomitch ? Do you get artifacts at all? Many thanks

    No artifacts at all. Clocking issues are usually the cause of crackling/pops. The Kemper MUST be the master, so you need to slave the RME clock to the Kemper. I have a tenuous clocking chain, but it works fine. I have an old M-Audio Profire 2626 connected via ADAT in to the Babyface Pro. The Kemper is connected to the coaxial S/PDIF on the Profire. So the clock is daisy chained Kemper --> Profire --> RME. I actually didn't expect it to work or be stable, but it's solid as a rock.


    I've also used a coaxial to optical converter and it also worked perfectly. Mine are the cheapo Monoprice ones.


    The other issue may be levels. If your S/PDIF level is blasting in to the RME it will distort and crackle. Also, have you checked your levels in Total Mix? If the levels are too high they will distort too.


    Lastly, I was getting some distortion from certain profiles because they run so hot. If it's only certain profiles that do it, try turning Rig Volume or the master volume down.


    Good luck!

  • That's all great.


    But it doesn't sound like the OP has such worries, and that was the question I was responding to.


    It's unlikely that someone looking to buy a small interface, is considering running a stand alone clock.

  • I think s/PIDF makes sense if it's a pro studio where you are recording/mixing things for other people.


    For the home studio it's not really needed. My interface has S/PDIF and I never use it. If I want a different sound I just re-record the part, no need for reamping for me ( even though I could do this with analog clean track). That is the luxury of home recording. I also prefer my layered guitar parts to not be 100% the same all the time. I am not a robot, lol

  • I'm still getting a lot of crackling on mine and have set the clock on the RME to be "Optical in" which I assume is the only way to make the Kemper the master?


    Thank you for this, @audiomitch , I really appreciate it.

  • I'm still getting a lot of crackling on mine and have set the clock on the RME to be "Optical in" which I assume is the only way to make the Kemper the master?

    That's pretty much it. Are the sample rates set at the same rate?


    Also, check your cabling. I only use 75 ohm coaxial cable that was designed for digital audio applications. A regular RCA patch cable might work, but may not be reliable.


    There's a yellow light on top of the Babyface Pro that turns from yellow to green once it's locked up. Make sure it's green, and the optical input is set to S/PDIF not ADAT.