Wish for constant internal latency!

  • One week to christmas, and I´ve got only one entry on my list of wishes: :whistling:

    Please let the KPA have a constant internal latency!


    At that moment the internal latency gets adjusted randomly. This is confirmed by Kemper tech support.
    Some of you may ask, what the problem is. There is no problem when just playing through the KPA. You won´t notice the random latency shifts. There is also no problem when recording track after track after track.


    So let me show you some scenarios, where the KPA fails!
    I use the KPA mostly in my studio as a billiant source of all guitar sounds imaginable. I also use reamping a lot.
    Many producers let the guitar player play through several amps at once, record the amps to separate tracks and mix those tracks to get a unique sound, where every single tracks adds something to the end result.
    This can be simulated by reamping one DI track through several amps. I always work like this, e.g. adding a crunchy Plexi tone to a Diezel Herbert heavy sound for more clarity.
    Now try to reamp some KPA profiles from one source DI track - you will end up with random phase shifts. This means the two or more reamped tracks will not be in phase and randomly change their sound when mixed together!


    You can record a DI track and a profile sound tracks via SPDIF at the same time on the left and the right channel. Try to use the DI track to reamp an additional KPA profile sound. It won´t be in phase to the initially recorded track.
    (interesting question: are the left and right channels in phase? I have to test it....)


    Think big an built a Bonamassa-style live rig with two or more KPAs, to play different amp profiles together with a splitted guitar signal. The FOH mixer will get two or more signals that are out of phase. He will not be able to handle the random changes in sound.
    You will have those changes in your inears, too, or on you monitor speakers.


    The KPA is the only digital device I know, that delivers no fixed latency. This limits it´s usabilty for reamping significantly, and other areas are also affected.


    I can reamp digital preamps like PODs or Eleven Rack, VST-amp simulations, miced amps, all from one source DI track - and all will be in phase. But as soon as I add one KPA reamp track, the phase is all over the place...



    I suggested Kemper tech support some kind of latency switch: fixed for reamping and studio use, and dynamic for live playing. Maybe this compromise can make the best of both worlds happen?



    I hope I will get some support for this request!


    :thumbup:

  • yes, I call it problem without hesitation!


    The subject was lightly discussed in several parts of the forum already - unfortunately only a few users seem to care about it...so this here is just another try to get some attention! For me this is one essential flaw of the KPA - as great as the unit is in almost every other aspect!

  • -1 Sorry


    But make it optional if it does get implemented. Why? Because the solution is for the latency to be raised across the board until there is enough spare room for any effect/processing combination rather than to optimize and bugfix until the latency comes down everywhere.


    Personally speaking I don't want higher latency, it's true that the latency changes per patch, and several patches feel bad as a result, too spongey and lacking the immediacy and fluidity of a real amp, it's subtle but it's enough to make me skip those rigs, when Christoph improved the latency back in March or April and took it down to below 4ms in most cases it made a huge difference to the feel and I really don't want to lose that.

  • ...The KPA is the only digital device I know, that delivers no fixed latency. This limits it´s usabilty for reamping significantly, and other areas are also affected....I can reamp digital preamps like PODs or Eleven Rack, VST-amp simulations, miced amps, all from one source DI track - and all will be in phase. But as soon as I add one KPA reamp track, the phase is all over the place...


    I can say with 100% certainty that the POD HD500 calculates latency on the fly and you can actually cause comb filters within its dual signal chains when an effect is only applied to one side (such as an EQ) and that many of the amps (or perhaps its the cabinets) in that unit can cause phase issues when virtually biamping. The usability of the dual chain in that device was a nightmare. While i can't speak to any latency issues, perhaps part of the issue is simply due to different profiles simply being out of phase with each other. As the profiles are made by emulating an actually miced systems which were made at different times without regard for phase coherency, I can see things might get a bit sticky reamping. Can you not simply phase align the tracks post reamp?


  • While i can't speak to any latency issues, perhaps part of the issue is simply due to different profiles simply being out of phase with each other. As the profiles are made by emulating an actually miced systems which were made at different times without regard for phase coherency, I can see things might get a bit sticky reamping. Can you not simply phase align the tracks post reamp?

    With reamping you can run into phase problems with differently miced amps and therefore with diffently miced profiles, too.
    That is right - but thoses cases are rare, believe me! I´m doing it for years and had one (!) case, where a reamped track caused problems.
    Of course you have to phase align the reamped tracks. That´s standad practice for reamping. It works with 99% of the tracks.
    The problem of the KPA is, that it´s inconsistent latency makes it always impossible to phase align tracks.

  • -1 Sorry


    But make it optional if it does get implemented. Why? Because the solution is for the latency to be raised across the board until there is enough spare room for any effect/processing combination rather than to optimize and bugfix until the latency comes down everywhere.


    Personally speaking I don't want higher latency, it's true that the latency changes per patch, and several patches feel bad as a result, too spongey and lacking the immediacy and fluidity of a real amp, it's subtle but it's enough to make me skip those rigs, when Christoph improved the latency back in March or April and took it down to below 4ms in most cases it made a huge difference to the feel and I really don't want to lose that.

    As you will understand, I personylly don´t care much about additional effects ;) my KPA is for studio use.
    But of course I understand your concern! I love playing the KPA, and I hate when it feels unresponsive.
    That´s why i suggested a "latency-switch".


    8)

  • +1 Agreed, as long as it's implemented as a switchable option. Having as low latency as possible when playing live is my #1 priority, although I will be reamping occasionally so the option of locking latency for that application does make a lot of sense.

  • With reamping you can run into phase problems with differently miced amps and therefore with diffently miced profiles, too.
    That is right - but thoses cases are rare, believe me! I´m doing it for years and had one (!) case, where a reamped track caused problems.
    Of course you have to phase align the reamped tracks. That´s standad practice for reamping. It works with 99% of the tracks.
    The problem of the KPA is, that it´s inconsistent latency makes it always impossible to phase align tracks.


    Are you saying latency shifts in real time without any changes at the Kemper? In other words with any profile loaded, there is variable latency? that would indeed be odd as we shouldn't be dealing with a multitasking machine here. I can think of why latency would have to be elastic as resources should be 100% dedicated to audio. Maybe CK will chime in...

  • Ups, yes that is bad.
    Different latency for different rigs (stack only or all effect slots used) would be acceptable - but the same rig ???

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  • just for further clarification:
    for reamping purposes one can live with any latency, as long as it a constant one!
    You must phase align the tracks afterwards anyway.


    the problem with the KPA is, that the internal latency gets randomly adjusted. You can reamp a DI track even with one profile several times, and end up with tracks all running out of phase to each other at random points!

  • just for further clarification:
    for reamping purposes one can live with any latency, as long as it a constant one!
    You must phase align the tracks afterwards anyway.


    the problem with the KPA is, that the internal latency gets randomly adjusted. You can reamp a DI track even with one profile several times, and end up with tracks all running out of phase to each other at random points!


    Why would you reamp a track with the same profile multiple times rather than simply copying the track? What method are you using to reamp? This is the first I've heard of this. There's a bunch of very dense guitar mixes using the Kemper out there on Youtube. I presumed they were reamped but perhaps they are all multitracking overdubs. There's one specific vid where the user has like 6 tracks of heavy guitars and he runs though how they sound with shelving EQs and how smaller guitars end up sounding huge, I'll have to search for it...

  • Why would you reamp a track with the same profile multiple times rather than simply copying the track? What method are you using to reamp? This is the first I've heard of this. There's a bunch of very dense guitar mixes using the Kemper out there on Youtube. I presumed they were reamped but perhaps they are all multitracking overdubs. There's one specific vid where the user has like 6 tracks of heavy guitars and he runs though how they sound with shelving EQs and how smaller guitars end up sounding huge, I'll have to search for it...

    of course I wouldn´t do it!
    I told it just to make clear, that even two recordings of the same profile won´t turn out to be equal in phase!


    You can reamp different multi-tracked source tracks. That´s standard practice.
    But it should also be possible, to reamp several tracks from one source track to combine the sound of different amps/profiles. And this is where the KPA fails!

  • now i found the answer of my problem


    Thanks for this explanation, i couldnt undertand where it was coming from !!!


    I am very disappointed of the studio / reamping use of the device


    I hope the check the forum and try to fix all those small details that make our lives hard