Profiling through Spdif

  • I think it would be a great feature for those of us that are making studio profiles (through our lovely preamps, EQs and various processing in the DAW)
    it makes sense to me to have some routing options for profiling, as equipment is changing it could open doors to profiling things like amp sims etc as well.

  • I often wish we could make more use of the SPDIF connection. Creating a second fx loop for a TC Mimiq in my case would be brilliant.

    Karl


    Kemper Rack OS 9.0.5 - Mac OS X 12.6.7

  • For profiling, SPDIF circuitry at the non-Kemper end may be impactful as the system is not calibrated for use with it. You’d therefore also be profiling the sonic characteristics of the SPDIF interface(s), which would be different to using the analogue input of the Kemper to re-capture the transient detail in the signals it sends out to profile. Clearly, Kemper achieves some voodoo levels of accurate profiling, and I’d guess the calibration to account for the known parameters of the analogue input and corresponding analogue to digital conversion stage is paramount to this. I'll admit I'm just guessing though.
    The Kemper sends out white noise signals/pulses and works out where the frequency response distorts due to amplifier clipping. This kind of graceful/progressive distortion characteristic is going to be a defining and desirable characteristic of the amp in question, and Kemper’s forte in terms of reproduction. Trouble is, when these same signals instead pass through a SPDIF interface, which is fixed 24bit and therefore headroom, if the amplitude of the test signal clips the digital domain it won’t be full of pleasing 2nd order harmonics or progressive, it’ll be absolute and full of offensive harmonics, as the signal peaks are literally cut off flat with no more bits left to represent them.

    Do you/have you already explored profiling your processing chain in your DAW that you want to capture via analogue inputs and outputs? You'd replace the mic with a DI box to take your return line-level signal down to mic level, right?
    By the same token, you’re also profiling the response of your audio interface inputs and outputs doing this, but at least if you run at the highest sample rate your system will permit you can retain as much of the fast-transient detail that the profiling system seems to send out and capture as possible, and you have control over the gain stages so you can trim things in a way that they don't clip the A/D stage.

    Ed / Audio Systems Engineer / Kemper Stage + Fender fan