Can you just create a loop and LISTEN to it while adjusting the definition up and down?
I challenge you to "just use your ears" and see if you can tell if the low or high harmonics (or overtones) are being distorted. You can report your perception of what's happening but not technically what the control does.
I challenge you to "just use your ears" and see if you can tell if the low or high harmonics (or overtones) are being distorted. You can report your perception of what's happening but not technically what the control does.
I think this is a case of "I'm not going to tell you how to build a watch. I will tell you what time it is."
So, three pages later and we don't have a definition of Definition. I'll have to unsubscribe. 
I challenge you to "just use your ears" and see if you can tell if the low or high harmonics (or overtones) are being distorted. You can report your perception of what's happening but not technically what the control does.
First of all, it's only a suggestion/question, I don't even know if it's possible to change the sound of a loop by changing the controls after the loop is made. I don't use the Kemper that way, I only play music and try to avoid tweaking as much as possible. Something either sounds good to me or it doesn't, I don't need to be challenged by anybody about it.
If you can't hear a difference then the control is useless. A definition of terms is useless as well, the sound is only perceived by the ears.
There is a lot of nuance in this discussion regarding harmonics and overtones. There are also undertones as well as sum and difference fequencies which I don't think have been mentioned. Or I missed it? Some of the signal processing theory in this discussion is based on linear system theory, but much of what is implemented in guitar amps is nonlinear.
I think it is safe to assume that Kemper uses the words harmonics and overtones in a loose way. The manual states 'Vintage amps distort the lower harmonics in the guitar signal which gives them their bluesy sound' This wording is potentially misleading and certainly non-specific. As such, I don't think it merits much technical discussion. So, what is left is purely pontification. The statement in the manual is almost useless, which is why I think the post was started. What does it mean to distort the lower harmonics? Does it mean to change relative amplitude, phase, frequency? And what does bluesy mean? Does it mean that it retains even order harmonics rather than resulting in odd order(more square wave) behavior? Defintely maybe. 
One can discuss and dive into the details that Helmholtz originally formulated. It is certainly interesting, but I don't think the wording in the manual warrants a discussion at that level. The wording in the manual is 'flowery' and pretty much devoid of any useful technical merit.
The original question will not be resolved until Kemper describes definition in a meaningful, technical way. My $0.02.
So, three pages later and we don't have a definition of Definition. I'll have to unsubscribe.
I really thought someone from Kemper might chime in on this one..... I don't think it would be giving away any secrets.
You are correct - perhaps I took that detail for granted or implicit and glossed over it. My mistake.
At the same time - resonant frequency does not necessarily refer to a harmonic. Those have specific nodes, whereas other resonant frequencies do not. Hence the term enharmonic.
No problem.
I would venture to say that all harmonics are overtones though...
Thank you for that discussion: it got me to look further into it, which is always a good thing.
No problem.
I would venture to say that all harmonics are overtones though...
Thank you for that discussion: it got me to look further into it, which is always a good thing.
Agreed. Discussion and debate where both sides learn is always good.
Overtones as I understand them are any (resonant) frequencies above the fundamental. Whether harmonic or inharmonic.
I think it may be worth noting that harmonics that are integer multiples (1x, 2x, 3, x4, 5x), when the amplitude of all harmonics are the same (that never happens in nature), and the transient is the same in all frequencies (also never happens in nature), the resultant sound is what most people would identify as a pipe organ (or perhaps a woodwind sound. That's essentially what additive synthesis is.
I don't think any control on the Kemper would adjust this harmonic series, because the further that one moves away from the harmonic series (with integer based multiples) to inharmonic (ex. 1.1x 1.2x, 3.4x) then the sound becomes metallic white noise-ish. Like pitches white noise, where there is no fundamental.
So, to get back to the questions, what does definition do: it could possibly adjust the amplitude envelope of higher frequencies. Higher frequencies are responsible for what we perceive as transients, which then in turn help to give clarity to a sound's attack part of the envelope.
I'll have to sit and listen and play with the knob. I'm just theorizing...
So, to get back to the questions, what does definition do: it could possibly adjust the amplitude envelope of higher frequencies. Higher frequencies are responsible for what we perceive as transients, which then in turn help to give clarity to a sound's attack part of the envelope.
I want to believe. I want to believe we'll get the answer to what it does. Meanwhile, I'm putting my money on definition predominately choosing to distort the lower harmonics on lower settings and upper harmonics on higher settings while discontinuing the distorting of lower ones.
the Definition contol for me sorts out the loud issues I get when playing through a loud PA and monitor.
my sounds sounded great on headphones and at low volume, but as soon as I pushed them up to gig volume they became all flappy and sounded horrible.
the dreaded Fletcher Munson syndrome.
after a few years of messing with eq's with some success
I recently purchased a new monitor QSC CP8.
playing this loud created the same problem,
Just by chance I tweaked the Definition control, turned it practically off and there it was, the sound I was after at high volume
Reverb can ruin your sound at high levels so those levels were pulled down aswel.
it's taken me a while to get to this stage, to be happy with my live sound.
such a simple thing to do.
the sound in my headphones has changed, but turning them up a bit sorts the sound out.
