It sounds like aharmonic notes in the background, sometimes a bit like a ball bearing rolling. Essentially it's adding in frequencies that shouldn't be there.
Oh I get it now, kinda like when my wife is talking I hear what sounds like lots of background noise!
Oh I get it now, kinda like when my wife is talking I hear what sounds like lots of background noise!
Nah, aliasing isn't that bad!!! Also, you don't have to stop playing when you hear it, unlike when the wife is talking to you.
In a lot of distorted profiles I get a high pitch sizzeling sound (around 9.5 to 10kHz) that, according to my logic channel EQ analyzer, shouldn´t even be there.
I thought one of the tweeter of my Yamaha HS80M is broken, so I changed them. But it is still there. Also when I use headphones.
I usually set a very narrow filter (with the kemper studio eq or the logic channel eq) at the forementioned 10kHz at -8dB. What I cut out is that alasing, I think.
But maybe that is a different problem! 
I experience this too. A lot of us have. It is not the same as cone cry or ghost notes. It's definitely in there. I find it's particularly apparent when bending more than one string, or bending one note against another static note. And, it is more prominent with gain. Some profiles are better than others. There may be a need to work that out in the profile refining process.
Take a rig, add as much gain*) as possible (Gain Max + boost in front of it or something like that) - play pinch harmonics on the high e-string on 14th++ fret. Listen. 
*) I really don't know why this aliasing stuff is an issue for so many, I mean... it sounds like crap with that much gain anyways... 
You"ve done it now Mikey,just watch this thread grow.
Or maybe not.
I experience this too. A lot of us have. It is not the same as cone cry or ghost notes. It's definitely in there. I find it's particularly apparent when bending more than one string, or bending one note against another static note. And, it is more prominent with gain. Some profiles are better than others. There may be a need to work that out in the profile refining process.
Actually, I think you have gotten intermodulation distortion confused with digital aliasing.
In the analog world, high gain absolutely produces subharmonics/ghost notes especially when playing harmonics. Listen to the solo of Metalica Blackend at the 5:30 mark. You can clearly hear a harmonic struck with 2 distinct notes which merge into one at the pitch is bent. If you listen to a lot of Joe Satriani, you've likely heard it in his music as well (2:09 of Circles of Surfing with the Alien is an obvious spot). You can hear it many of Pantera's tracks as well. There's plenty of recorded examples of double stop bends in which a 3rd note is audible though the guitarist only played 2. This is due to the very nature of distortion. Distortion brings out harmonics. In the case of a harmonic played, you are dealing with a signal with a weak fundamental. Given the fact that distortion brings out harmonics and its compressing nature, I think you are simply hearing the natural effects of distortion. Regarding double stops, intermodulation distortion is absolutely audible and would account for a thrid note being heard when only 2 were struck (look it up if you doubt the phenomena). IME, the Kemper reacts more like one would expect an analog system to sound than what I would expect digital aliasing to sound. I'm not saying CK and crew have created a absolutely perfect product, but be careful what you ask for. Let's hold the Kemper up against real world examples of what real amps sound like versus a perfected ideal.
aliasing (in this case i think the correct term is actually imaging) can be described as frequencies above 1/2 sample rate (the nyquist frequency) reflecting downward off of this limit. this is what makes them obvious to me in the kemper, since the artifacts move in the opposite direction of pitch, so bends up have downward-moving artifacts. these come out quite strongly with the use of feedback. i have never ever heard anything remotely like this in any real tube amp. if you don't use string feedback, try an ebow, it exposes the problem quite easily on medium gain settings. once you identify it, you will begin to hear it in less obvious settings... if not, ignorance is bliss...
more info here: http://en.wikipedia.org/wiki/Aliasing
aliasing (in this case i think the correct term is actually imaging) can be described as frequencies above 1/2 sample rate (the nyquist frequency) reflecting downward off of this limit. this is what makes them obvious to me in the kemper, since the artifacts move in the opposite direction of pitch, so bends up have downward-moving artifacts. these come out quite strongly with the use of feedback. i have never ever heard anything remotely like this in any real tube amp. if you don't use string feedback, try an ebow, it exposes the problem quite easily on medium gain settings. once you identify it, you will begin to hear it in less obvious settings... if not, ignorance is bliss...
more info here: http://en.wikipedia.org/wiki/Aliasing
From the Dr Z Forum in a discussion invloving the Maz 38
QuoteThe third effect is what's heard on the Maz 38 with the preamp cranked. A lot of amps do this and is considered normal. I remember hearing that on cranked amps 30 years ago. What I'm talking about is when you hold one note on one string and bend another at the same time, most obvious on high notes. What you hear is a note lower in pitch and level than the notes you're playing and seem to go in the opposite direction. As you bend up you'll hear this "difference" note going down. Amps with nice big output transformers seem to do it the most. Turn the bass down and it'll reduce the effect. It's a normal thing to overdriven amps.
Read more: http://ztalk.proboards.com/ind…thread=4552#ixzz2HVBtVdqt
Here's another case of users of real tube amps describing the phenomina: http://www.el34world.com/Forum/index.php?topic=6687.0;wap2
Again, I'm not saying the Kemper is without flaw nor that there isn't room for improvement. But high gain can bring about some very unexpected behaviors even in real world tube amps. Maybe its aliasing, maybe its simply modeling the negative aspect of analog distortion. All I'm saying is be careful what you ask for regarding changing the core way that the Kemper sounds...
Thanks Will!
no those are combination tones, which are audible with pure sine waves in air, completely different and unrelated phenomenon.
no those are combination tones, which are audible with pure sine waves in air, completely different and unrelated phenomenon.
Here's an actual example of digital aliasing in the extreme. Note that the resultant artifact is atonal, almost sounding like a ring modulator. http://www.sic.rma.ac.be/~xne/el401/aliasing/
Again, not saying the Kemper is perfect. But what I hear is more akin to a ghost note or intermodulation distortion, things which happen in real amps, rather than aliasing which does not in any way sound melodic/harmonic.
In a lot of distorted profiles I get a high pitch sizzeling sound (around 9.5 to 10kHz) that, according to my logic channel EQ analyzer, shouldn´t even be there.
I thought one of the tweeter of my Yamaha HS80M is broken, so I changed them. But it is still there. Also when I use headphones.
I usually set a very narrow filter (with the kemper studio eq or the logic channel eq) at the forementioned 10kHz at -8dB. What I cut out is that alasing, I think.
But maybe that is a different problem!
This is not aliasing.
I experience this too. A lot of us have. It is not the same as cone cry or ghost notes. It's definitely in there. I find it's particularly apparent when bending more than one string, or bending one note against another static note. And, it is more prominent with gain. Some profiles are better than others. There may be a need to work that out in the profile refining process.
This is not aliasing either.
What you hear is a natural phenomenon of distorted amps, called intermodulation. If you don't like it, turn the Gain to zero 
Be aware that every single amp that has been profiled features that same amount of intermodulation as the respective profile. If that was not the case, you could read dozends of reports, that the original character of the anp has not found its way to the profile.
Aliasing is only noticable on single notes.
In a lot of distorted profiles I get a high pitch sizzeling sound (around 9.5 to 10kHz) that, according to my logic channel EQ analyzer, shouldn´t even be there.
I thought one of the tweeter of my Yamaha HS80M is broken, so I changed them. But it is still there. Also when I use headphones.
I usually set a very narrow filter (with the kemper studio eq or the logic channel eq) at the forementioned 10kHz at -8dB. What I cut out is that alasing, I think.
But maybe that is a different problem!
It could be an overloaded input? Did you try to reduce the clean sense setting? Did you get it with a high output humbucker guitar?
I just finished thoroughly profiling 7 different amps (the profiles sound great overall), though every profile exhibits an aliasing artifact on high single notes in the moderately-high to high gain range that is absolutely not there in the amps themselves. I am highly anticipating this next firmware release... meanwhile, I am blown away by my KPA tones!
Best example of intermodulation is the end of Working Man. We're all experienced that, even tried intentionally to play around with those sounds. Embrace the weirdness!
The aliasing that was there in the Kemper was not always an issue. Some profiles showed no signs of it, and I avoid adding much gain to most profiles (sometimes it works, sometimes it doesn't). Those that did (even cleaner ones), always seemed to have something funky going on in the high end. It really was more apparent with higher gain. I haven't spent enough time with the KPA tonight (too much on here and TGP!), but I've noticed a change in the overall tonal response, it seems. Still wanting to get more clarity and chime out of some profiles, but I've not had the KPA long enough, nor enough time to really learn how to get the most out of it.
Thanks for v1.6!
