Spiky attack

  • Hi,


    I'm a new Kemper owner, had the PowerHead for a month or so. First of all, let me say Kemper is just an awesome product, and I'm very happy with it. I have recorded and gigged with it successfully, and created a few profiles of my own amps myself, with good results in most of the cases.


    However, I do have one problem with the actual sound: the attack can be extremely "spiky" when you hit the strings hard. This is difficult to explain, but there is a quick popping sound in the beginning that doesn't happen with a real tube amp. This happens mostly with the first note/chord after a short break, not so much if you play constantly. This can be witnessed with studio monitors or headphones, but is most apparent in high volume with a guitar cabinet. Some profiles are worse than the others, but I think this happens with most of them to some extent.


    I have checked that this is not because of any effects in the signal chain, or settings in the Amplifier section, but it does happen regardless. I can also hear and feel a difference when profiling and comparing the reference sound to the profiled sound.


    This is getting quite annoying, as this is practically the only issue to me that separates the Kemper tone from a real tube amp.


    Any advice? Is my Kemper faulty, or do others experience this as well?


    -ax

  • This has been reported and documented. Kemper, it seems, has no interest in fixing it.
    See here.


    Sorry, man. I hope CK's explanations make things sound good again for you :whistling:


    You can try reducing 'power sag' and 'definition' - it would change the sound, but if you could work around that...

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • Thanks Quitty, I read the thread you referred to. It is the exact same problem.


    Unfortunately reading this doesn't make things sound better, but rather makes me very disappointed. From other threads I've though Mr. Kemper is quite customer-oriented, but in this case he seems to downplay paying customers who have found a flaw in his product, and shows no interest in fixing it. Very sad. It should be understood that if Kemper doesn't accept customer feedback and improve the product accordingly, someone else will create a better product and the customers will be gone.


    I found this flaw by listening, not by looking at waveforms, so it does impact real life performance. Real tube amps don't suffer from this problem, so Kemper's claims about replicating tube amp sound are false until this is fixed. I know there are workarounds, but we as users should not have to worry about this type of things.


    -ax

  • This has been reported and documented. Kemper, it seems, has no interest in fixing it.
    See here.


    I used to pay attention to the spiky behaviour as well in the past, but for some reason this doesn't bother me anymore 8| Since the beginning of that thread there have been some changes in the way clean sense is set and the output levels are measured/shown with the leds (right?) and maybe some other global things that I am not even aware of (I don't have to touch on the default settings anymore).


    I have also moved mostly to other profiles/rigs, learnt how to use EQs before and after the amp section in a musical way and modified my guitar quite a bit etc. I might even have changed my playing style subconsciously haha!


    I checked the waveforms of a recent recording project where I used Lasse Lammert's BOMBED! profile in its stock form (which was spiky back then) and there were no (bad-sounding) spikes in any of the waveforms. Here is an example:


    https://dl.dropboxusercontent.…55653919/bombed%20wav.png

  • It is interesting - and relieving :D - to see that the very guy who denounced this phenomenon the most is no longer bothered by it :)
    In the end, everybody's happy! :D

  • I just swapped profiles. Couldn't have guitar tracks taking such an excessive overhead in any tracking session - there was very clearly something wrong there.
    Don't know if it was fixed - i haven't used the offensive profiles for this very reason - if something was changed, i'd love to know.


    As for learning to use the Kemper, i'm sure i have much to learn. I have, however, owned a Profiler for over a year now and am using it on a daily basis in every conceivable situation.
    No amount of pre-EQ changes transient response and whatever does, also changes the profile's dynamics. There should be a solution, not a workaround.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • Couldn't resist running a quick test ... First spikes are pick scratches and the rest are strumming open strings with the LL-BOMBED! profile.


    I just can't reproduce the bad-sounding (kinda "snapping/clipping" sounding) spikes anymore (latest firmware). BUT, I noticed that if I reamp the same DI file with different noise gate values, then the spikes at the beginnings might get "snappier" (see, e.g., the red sections in the figure).


    https://dl.dropboxusercontent.com/u/55653919/spikes.png


    Maybe a stupid suggestion, but lowering the noise gate value could help some.

  • Noise gate is at 0.0 here. The Profiler is actually hilariously quiet.
    Your findings are interesting. Some of your strums are visibly gentle, but really, even with the noise gate this is very, very different from what you found out last time.
    The previous scopes looked like the pick scrapes you just captured.


    Interesting. Might be a good time to re-test some old profiles?


    OP: Make sure you're on the latest firmware, and do a system reset just to make sure.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • I noticed this phenomena too and thought maybe I was crazy or just picking too hard, but it is true and it is there with certain profiles. (Mostly high gain ones as already mentioned, such as Lasse etc..)

  • There's a distinct "background noise" to the profiles by Keith Merrow and Lasse Lammert, imo. That's why I don't use them anymore. Probably high frequency content from the amp that's accentuated somehow.

    Not to mention the aliasing. To me that made them completely unusable.

  • I too have a real problem with Kemper technical showing no interest in this problem. See my post about turning the LFC function OFF to fix the popping sound. It works for me and I can set all amp and effects settings to extreme values without a single pop. I need others to test this out, so please try it and report back. Thanks,


    Mark