Be aware of the digital sonic artifacts (aliasing) in your KPA!

    Yes, digital aliasing has been a problem in certain areas (as I & others have pointed out numerous times on this board) but it is now being addressed as I write this - Kudos to Kemper for continuing the upward quest towards 'tonal Nirvana'... We aren't there yet, but the goal line is rather clear in sight at this point! 8)

    All modelers known to man 8o

    Quote from Radley

    Yes, digital aliasing has been a problem in certain areas (as I & others have pointed out numerous times on this board) but it is now being addressed as I write this - Kudos to Kemper for continuing the upward quest towards 'tonal Nirvana'... We aren't there yet, but the goal line is rather clear in sight at this point! 8)

    Look man, you have your own 'issues'. My Kemper sounds great.

    Quote from Radley

    Yes, digital aliasing has been a problem in certain areas (as I & others have pointed out numerous times on this board) but it is now being addressed as I write this - Kudos to Kemper for continuing the upward quest towards 'tonal Nirvana'... We aren't there yet, but the goal line is rather clear in sight at this point! 8)

    Well, no piece of gear has ever reached the level of 'Tonal Nirvana', the KPA will be the first.

    Regarding the 1.0.9. FW release:


    Good news: The aliasing in the distortion stomps sounds like it's gone! :thumbup:


    Bad news: The aliasing in the high gain amp profiles is still there! :thumbdown:


    I am now more concerned than ever that when Kemper told me that the amp aliasing was different than the dist stomp aliasing, that this might be beyond a FW fix. It seems like the nature of the aliasing sound seems ever-so-slightly different than it did in 1.0.8., like there is a bit more "burst" when you hit high notes hard.


    CK, will this ever be corrected in firmware?

    NM

    Edited once, last by mikeb ().

    Quote from mikeb

    You may need a full reset as my Kemper did. After this the aliasing sound was totally gone and I believe it has to do with some internal gain setting than actual aliasing. In any case, a Flash memory format followed by a system restore will most likely fix your issue.


    No difference for me here. I hear these "aliasing" effects on the Wet Queen patch only with the distortion pedal (still slightly with the amp itself), I tried doing a flash format and init and reinstalling factory default rigs, still there. I'm pretty sure this update hasn't addressed this particular issue as otherwise it would have been mentioned in the release notes (and we'd hear it).

    Quote from Per


    No difference for me here. I hear these "aliasing" effects on the Wet Queen patch only with the distortion pedal (still slightly with the amp itself), I tried doing a flash format and init and reinstalling factory default rigs, still there. I'm pretty sure this update hasn't addressed this particular issue as otherwise it would have been mentioned in the release notes (and we'd hear it).

    Ah ok! Interesting. I'll stick with 1.04 I guess. I don't hear any aliasing in that firmware.

    V1.09 aliases in the same fashion as Demo 5, below. In other words, stomp alone sounds good, amp alone is a little gritty, and stomp+amp aliases noticeably.


    I've added the following result to the SoundCloud demo suite just now :


    6) WQ 109 Factory Restore


    -djh


    Quote from miles

    Bad news: The aliasing in the high gain amp profiles is still there! :thumbdown:


    I am now more concerned than ever that when Kemper told me that the amp aliasing was different than the dist stomp aliasing, that this might be beyond a FW fix. It seems like the nature of the aliasing sound seems ever-so-slightly different than it did in 1.0.8., like there is a bit more "burst" when you hit high notes hard.


    CK, will this ever be corrected in firmware?

    In my opinion the aliasing even has become worse with the new FW!
    "burst" describes the strange attack quite well. You can hear that distorted white noise up-sweep very clearly with gain maxed, just hit a high note hard. Some notes sound worse than others, here on most hi gain profiles the C# on the B string 14th fret sounds totally destroyed. And I mean TOTALLY DESTROYED! like if there´s a Devi Ever lo-fi Fuzz pedal engaged...lol...
    :thumbdown:

    Quote from schneidas

    I can definitely hear this in your soundsamples.
    Has Kemper acknowledged the problem?


    Schneidas,


    What I know is: They're aware of the problem, they tried a quick fix, and apparently decided against it.


    [Begin Conjecture]


    What I suspect is: Sometime after v1.04, Kemper decided that they wanted to free up some DSP for future improvements, and took the stomp block out of the oversampling section as a performance optimization. While this is a good idea for linear effects, it's unsatisfactory with distortion pedals hence the problem. My guess is that they've been experimenting with making stomp oversampling conditional on whether there's enough DSP available for the task, which may not be the case when running both the MetalDS pedal and amp in oversampled mode under the current feature set.


    If that's the case, the solutions would be to try to either a) Optimize the code, b) Drop the distortion pedals, c) Roll back to a v1.04-era functionality or d) Just live with it. And that's probably why Kemper is being rather quiet. Unless the box is expandable in some way, it's the kind of thing that might lead to a faster DSP in the next-gen (rack?) KPA.


    [End Conjecture]


    ^^ I realize I'm sticking my neck out with that stuff I just said, and at any moment CK could pop up and call me a horse's ass. But I'm willing to risk that, because any new piece of information helps increase our understanding of The Mighty Lunchbox.


    -djh

    If this is the scenario, I´d vote for "all DSP power for amps"!!!!


    The most important part of the KPA for me is it´s ability to deliver countless hi quality amp sounds for instant studio use.
    I don´t care for it´s FX-department at all. I have lots of stomp boxes that all sound better anyway.

    Quote from r_u_sirius

    If this is the scenario, I´d vote for "all DSP power for amps"!!!!


    The most important part of the KPA for me is it´s ability to deliver countless hi quality amp sounds for instant studio use.
    I don´t care for it´s FX-department at all. I have lots of stomp boxes that all sound better anyway.


    +1


    Anyway I hope that this is not the case at all..I just do not want to see a KPA std then KPA ultra ,then II because of lack of power ;)

    Quote from r_u_sirius

    If this is the scenario, I´d vote for "all DSP power for amps"!!!!


    The most important part of the KPA for me is it´s ability to deliver countless hi quality amp sounds for instant studio use.
    I don´t care for it´s FX-department at all. I have lots of stomp boxes that all sound better anyway.

    I agree!
    It might not be going away until the KPA II. :(

    As I have announced earlier in another thread, we have addressed aliasing problems for the distortion stomps. In 1.09 they have the same quality as the amp itself. Before 1.09 there were no changes.
    A system reset will not have an effect.