Loud "internal" clipping with a specific rig - Input and output levels are fine

    Quote from thebrushwithin

    Alex, you are not alone, in this matter. I had this same sound on several profiles, and it was unpredictable, as to when it would occur. I ended up sending it back to Kemper, and was told by my sales rep, that they couldn't really find the problem, but replaced the board in it anyway. So, over the past year, when is got it back, everything seemed fine, and so I took it out on a gig last week. Suddenly, one of my lead patches started doing this really loud clipping noise, just like before, and I had to stop using the patch, just to get through the gig properly. A hard strum brings this obnoxious noise out, and I cannot figure out what is causing it either.


    Odd, a hard strum fixed the issue. Maybe you turned something off and you didn't figure?
    Did you save the faulty rigs and tested it with the new KPA? Did you still have these ones?

    No, a hard strum causes the issue. Before I had it repaired, it was happening on many patches, pretty randomly. But last week, it would occur on only one patch. My current problem seems to be only with one rig, unlike before. Before the repair, it started with the same "hard strum" sound problem, but finally became so bad that I had serious loud noises, even with NO signal (unplugged input), that resulted in a "DSP error" message.

    Quote from thebrushwithin

    No, a hard strum causes the issue. Before I had it repaired, it was happening on many patches, pretty randomly. But last week, it would occur on only one patch. My current problem seems to be only with one rig, unlike before. Before the repair, it started with the same "hard strum" sound problem, but finally became so bad that I had serious loud noises, even with NO signal (unplugged input), that resulted in a "DSP error" message.


    I understand.. maybe a flash init would have been useful before sending for repairing, but anyway..


    Can you send me the faulty patch if it is not a commercial profile?? Alternatively send me a pm with the patch name, maybe I already have it.



    Quote from nightlight

    The noise goes away if you turn off the cab section. What if you try a different cab? We can probably narrow this down, but as mentioned, since Kemper Amps has reproduced the issue with said profile, in all likelihood there's something defective.


    I'll try as soon as possibile nightlight

    Quote from nightlight

    The noise goes away if you turn off the cab section. What if you try a different cab? We can probably narrow this down, but as mentioned, since Kemper Amps has reproduced the issue with said profile, in all likelihood there's something defective.


    So, I tried to change the cab (taken from the rigs I have in my KPA); I heared the noise only with a couple of cabs (for example, the cabinet Mesa Stiletto from Gary Moore Lead profile, available in RE).


    I tried also to change both cabinet and amplifier and I was able to reproduce the noise too. Here you can download the rig: the amp is from Acoustic A profile, while the cab is from Gary Moore Lead profile. They're both free, so no copyright issue here. I don't want to upload it in RE because it's a "faulty" rig.


    But the loudest noise I heared was with this rig cabinet: Ada 3tm Bright Clean. Try, for example, to load the original profile and turn off the amp: it's like an explosion!


    I think it's all matter of profiling volume.

    Quote from alex_it

    Update: if I'm playing with a ordinary rig and I switch to the next rig via the "rig buttons" on the right, and the next rig causes the clipping (i.e. the one that I posted before), the output led is fully red. If I stop and resume playing, with the same rig, the led stays green. ?(


    This is an interesting behaviour I found with the Morgan AC20 profile created by rmpacheco in the rig exchange. When I switch to the profile, the output LED instantly becomes red and stays that way for about two or three seconds before going green. I don't hear any clipping though, though I probably should do a recording to confirm.


    I think this behaviour only became evident in 2.6, but can't confirm it. Perhaps a support ticket on the issue is in order? I'll create one.

    After listening to your audio recording, it sounds like you and I have a similar issue (see my post about LFC pops). I have spent days trying to diagnose this and whilst the problem seems to be only on certain profiles, I have found that I can tweak some of the clean factory profiles to exhibit this problem. The solution which fixes it every time for me is to go to page 8 in the "System" menu and tick the "LFC Off" box.


    I already sent a backup and a couple of sound files to Kemper, but they say they can't reproduce it. I've tried everything I can think of - reloading the firmware; various reset methods including factory reset and initialisation of flash memory - all make no difference. The ONLY thing that completely cures it is switching off the LFC. Try it and see if it works for you too and let me know.

    Quote from Silk_Purse_Productions

    After listening to your audio recording, it sounds like you and I have a similar issue (see my post about LFC pops). I have spent days trying to diagnose this and whilst the problem seems to be only on certain profiles, I have found that I can tweak some of the clean factory profiles to exhibit this problem. The solution which fixes it every time for me is to go to page 8 in the "System" menu and tick the "LFC Off" box.I already sent a backup and a couple of sound files to Kemper, but they say they can't reproduce it. I've tried everything I can think of - reloading the firmware; various reset methods including factory reset and initialisation of flash memory - all make no difference. The ONLY thing that completely cures it is switching off the LFC. Try it and see if it works for you too and let me know.

    Hi, I tried to set the LCF off in my rig but nothing changed, clipping is still present. Indeed, some time ago I tried to downgrade the firmware when the problem occured, a firmware without the LCF feature, and the result was the same.
    I also tried to reproduce the issue that you described in the other thread, with the S.Mehl 50 clean profile, but following your instruction, I couldn't hear any clipping. The output led became almost red though, with rig volume untouched (noon)

    Ok thanks for trying the LFC. Sorry to hear it didn't make a difference in your case. I presume you don't have any solution yet? It's very frustrating to have these issues which should not happen on a unit of this price. So far I have not had any ideas to try from Kemper technical support. They are unable to reproduce it and I wonder whether they are taking this seriously.

    Quote from Silk_Purse_Productions

    Ok thanks for trying the LFC. Sorry to hear it didn't make a difference in your case. I presume you don't have any solution yet? It's very frustrating to have these issues which should not happen on a unit of this price. So far I have not had any ideas to try from Kemper technical support. They are unable to reproduce it and I wonder whether they are taking this seriously.


    I feel sorry for you. In my case the kemper support was able to reproduce the issue, so others KPA owners.
    Are the output led and clean sens ok for you? Is your guitar kinda boomy?

    Alex, I had something similar. I was getting a "popping" noise in my speakers, only from one note and only on some patches and only when played harder.For the bad patches I added an EQ and adjusted the mid between 410 -435 hz and then lowered the mid gain and Q settings. I also lowered the low at around 20 hz and adjusted the Q setting down. I also adjusted the effect level back a bit. Depending on the kind of effect the mid EQ would need to be adjusted to find the offending Hz that made the pop. For example: with a phaser it was 410hz and with a fuzz it was 435 hz.


    Try finding if it is just one note making the pop or many and adjust out the offending frequency. It might be the speaker I am currently using that does not like this frequency as I did not notice it on my previous speaker. You might have to play around to find the freq to cut for your gear. It worked for me
    Hope you get it solved.


    Drog

    Edited once, last by drog ().

    Ok, after playing around with some different amps and setups, here is what I found. Going into a studio monitor directly from the monitor out, then turning up the output knob/ volume past the zero point creates the distortion for me. But oddly only on the 5th string, 11th fret (Ab/G#) note. This will create a loud popping noise in the speaker. If I leave the kemper monitor level at the zero level, then crank up the studio speakers amp, there is no popping noise. I can turn the studio monitor full blast and no popping noise. Its only if I use the monitor output level past the zero mark, turning the volume knob (I have it set to control my monitor only).


    I did not notice this effect while running into a guitar cabinet, oddly enough.


    So for now I will turn up the studio monitor amp and turn down the Kemper. I will test this with my PA speaker next rehersal.

    Quote from drog

    Alex, I had something similar. I was getting a "popping" noise in my speakers, only from one note and only on some patches and only when played harder.For the bad patches I added an EQ and adjusted the mid between 410 -435 hz and then lowered the mid gain and Q settings. I also lowered the low at around 20 hz and adjusted the Q setting down. I also adjusted the effect level back a bit. Depending on the kind of effect the mid EQ would need to be adjusted to find the offending Hz that made the pop. For example: with a phaser it was 410hz and with a fuzz it was 435 hz.


    Try finding if it is just one note making the pop or many and adjust out the offending frequency. It might be the speaker I am currently using that does not like this frequency as I did not notice it on my previous speaker. You might have to play around to find the freq to cut for your gear. It worked for me
    Hope you get it solved.


    Drog


    Drog, in my case the speaker doesn't matter, because I can hear the pop also with the headphones/spdif out. Plus, the note/frequency I play with the guitar seems ininfluent. Maybe you're clipping your speakers input?

    Hi, new Kemper user here. I just finished profiling a few patches from my POD XT and noticed the popping issue on a Blackface type patch. It only occurs on the top string when hitting it hard. I noticed that reducing the Pick attack parameter on the Kemper improved things but the issue was still there. I checked all levels to and from the POD and nothing was clipping during the profiling BUT I decided to re-profile with the output setting of the POD slightly lower and low and behold this eliminated the issue. I think it may be possible for the Kemper to sample clipping or other artifacts during the profiling process and although not audible during auditioning, it affects the resulting profile. Anyway, hope this helps anyone facing the same problem.

    Quote from JonnyB

    Hi, new Kemper user here. I just finished profiling a few patches from my POD XT and noticed the popping issue on a Blackface type patch. It only occurs on the top string when hitting it hard. I noticed that reducing the Pick attack parameter on the Kemper improved things but the issue was still there. I checked all levels to and from the POD and nothing was clipping during the profiling BUT I decided to re-profile with the output setting of the POD slightly lower and low and behold this eliminated the issue. I think it may be possible for the Kemper to sample clipping or other artifacts during the profiling process and although not audible during auditioning, it affects the resulting profile. Anyway, hope this helps anyone facing the same problem.


    That's my thought too. Some clean amps may have been profiled with very high volume/ soundboard preamp gain and the refine process may possibly not show any issue.

    Hi, another new KPA user here. I found this thread looking around for a answer to fixing the Loud pop I am getting, usually when strumming a bit hard or doing a palm mute. The first time I heard it, it scared the heck out of me and I thought for sure I may have damaged my speakers. I am using a KPA Power amp going into a 4 way cab through monitor out and also studio monitors through the main XLR outs. I get the pop on both and it appears to happen only on the direct amp profiles that I created. I primarily like to play with very clean tones and they seem to want to clip the output light much easier than the distorted tones. I can make the pop go away by reducing volumes to the point that I don't much like the quality anymore. But I wondered whether this pop was coming from the profiling process being set up with to hot of a signal. When I created it it sounded so good right away. The clean tone was just what I was looking for but it clips to easily. I tried tuning the amplifier settings but nothing really makes the pop go away or reduces the output clipping other than the amp volume. If I turn up the gain it distorts and there is no pop but lowering the gain all the way it makes it possible to happen. I had tried reducing the volume on the amp being profiled for a lower level during profiling but the quality is not as good as the one the makes the pop. I don't know if anyone else is expieriencing the same pop but mine sounds like a small highly pressured balloon popping. I read some other threads and there is talk of this being software related but I think what JonnyB said makes a lot of sense. I will need to experiment some more with profiling levels of the same amp setting.

    As long as the Output LED gets red, the Volume is too high. But you can compensate through the Master volume, or raising the active cabs' one (or rising the Kemper's poweramp's one) in order to keep the same SPL.


    It's natural that clean sounds clip much more than distorted sounds, and if the output LED goes heavily red you're basically making the D\A converter tilt!