Posts by Per

Cool stuff. What riff challenge is this?

Then maybe it simply multiplies the output signal of the amp block/loop when gain is low, but I’m not sure why you’d then get a crossover mix sound effect when extreme settings are used.

Why do you think it’s complex? It’s a very simple addition function, even less complex than the Direct Mix control.

Well obviously only the Kemper team really knows how it works but the evidence is there in the tests that I did. I think you’re over-complicating a simple thing.

I just don’t see a reason to believe in a complex solution with special cases for every distortion, compression, ducking etc, delay dirt function, combinations of stomps etc, when there’s a very simple answer that matches the observed behavior.

If a boost were expected by the user in front of the amp wouldn’t you expect clean sens to actually modify the input volume? But it doesn’t because if it did then the amp gain (distortion) would respond accordingly, same as if you adjusted the volume pot on your guitar. Clean Sens doesn’t act like that. Try it, roll back the volume on your guitar and see how the amp sounds, then bring it back up and lower the clean sens setting. They’re not doing the same thing.

Instead the only location where stomps are affected by the clean sens setting is post amp/loop block.

Then you can actually hear the mix itself if you use extreme settings on the Sens settings.

Why would there be a complex reason for this?

There’s a very good reason that I don’t think there’s a complex reason for this - It’s made by humans. We are lazy creatures, the only reason we invent or engineer stuff is to avoid having to do a much more laborious thing. So we apply smarts instead. The smartest most intelligent most elegant solution to a problem is the simplest one. I think Christoph and his team are very smart, and I just don’t think they’d expend that much effort to deliver the same behavior as a pretty simple solution.

The KPA isn’t that smart. What’s the reason you think there’s a complex intelligent processing with distortion rather than a much simpler approach? If it were that smart why would it only apply up to a certain pint in the signal chain?

You can hear the crossover mix of clean if you make the sens parameters extreme enough, it’s possible that clean sens isn’t the full throw of the dial but you’d need to test that somehow t figure out how much, e.g. perhaps make a profile with the gain set to 100% (but with a very clean sound) and then just measure when the volume started to increase with a high clean sens setting.

if you have the amp block bypassed I imagine it simply engages clean sens at 100% at the location of the amp/loop. Again just check by using a distortion stomp to see at what point in the signal chain it applies it.

There's another test you can do to determine how much of a factor that is. Set Clean Sens to its minimum, then adjust the Direct Mix in the amp block to be slightly higher than zero, see if it gives you a similar effect on those gain laden profiles.

Where is the actual gain knob in either? I don't notice anything other than the expected result of what the manual and I've described. Any difference can be accounted for by the mix of "clean" signal in with the distorted signal if the gain isn't at 100%.

Despite the black-box nature of the Kemper I think it really is as written in the manual based on my experiments.

The most difficult to grasp part is how Clean Sens is utilized in the amp block. If you take it as written, it really is operating in a similar fashion to the loop mix pot on most amps, it mixes between a parallel clean path that doesn't go through the pre-amp and the output of the amp. At max therefore it should make the Clean signal twice as loud.

The thing that makes this more complex is that this is also attenuated by the "Gain" control on the amp itself. So when Gain is at 10 that parallel clean path is completely muted, at 0 the parallel clean path has a value of 100%.

The tests I did in the other thread bear this out. With extreme settings the blend itself is audible as you adjust the Gain dial.

The reason I suggest using a distortion stomp to test with is that this is reactive to volume. Most other FX aren't. This makes it very easy to audibly tell whether the signal reaching that stomp is lower or higher in volume than before as you modify the Sens values.

I continue to believe that Clean Sens is just the volume/mix of a clean signal in the amp block output, and that Distortion Sens is just a modifier for the Gain dial position on the raw amp (not including the clean blend which I believe is locked to the actual gain dial value itself).

Therefore I currently believe this is the case :

PreAmp gain level = Gain knob + Distortion Sens value.

Amp output signal = Mix(Amp Block Input signal * Gain knob setting, with PreAmp output, by Clean Sens setting).

I believe that if you utilize a loop then you can substitute loop for amp and preamp in the second line.

In any case this means that Clean Sens will result in a net volume gain from the loop/amp block when the gain setting is lower. Distortion Sens will not result in any change except to the drive level of the PreAmp.

The input LED is anyones guess, I don't have my Kemper next to me to test out but it could either be just the raw input signal multiplied by the Clean Sens setting or it could be the the magnitude of the signal going into the amp block or loop (if it comes first) after it has been multiplied by the Clean Sens setting. In either case it doesn't actually represent the magnitude of the signal that actually goes into the signal chain which remains constant.

To sum up - the Kemper does not have a control for attenuating input.

It’s a confusing subject because the assumption is that the sens settings being in the input section would affect the input. They don’t.

Even worse they affect the so called Input LED. But it doesn’t even appear to be the input LED, it’s the output LED for the clean portion of the signal at some location in the signal chain.

Clean Sens is not Input Gain.

Quote from Wheresthedug

But if you put a Loop in Stomp A and send this to an amp, interface or dask and check the level hitting them you will see that this also happens for literally the first point in the chain. Therefore the logical conclusion seems to be that it does work on the input section not the output.

You can also see this on the KPA itself by monitoring the input LED. High CLean Sens settings turn this bright red whereas low Clean Sens leave it green. That should be monitoring the input signal not the output. The LED measure doesn't change even when no processing is being applied. You can test this by turning off all blocks (Stomps, Stack and Effects) just for good measure. Now set Main Output to Git + Processing. The manual clearly says that this mearly sends the input guitar signal straight through at the same level as it came in but it passes through the AD/DA converter first. Changing Clean Sens makes no difference to the audible output level (which is confirmed by the input meters on the desk). However, the LED still changes from green to red and if I hit the strings hard enough I can make the sound clip even though the level hasn't changed. To my mind, that implies the signal is being clipped on the input AD convertor but the level is being adjusted later in the chain before sending back out through the DA converter.

I found you need to ignore the input LED. Check my post in the linked thread.

It's possible that once a loop is used it changes the location within the signal chain of the change, however you can demonstrate that when no loop as active the clean sens only affects things after the amp block.

The easy way to see this is simply using the test case in the linked thread. As you know, a distortion stomp will sound more distorted the higher gain the signal going in to it. This makes it easy to determine if there's an actual change in signal level reaching that stomp. Place the distortion stomp before the amp block and play with the sens settings. The distortion will not change. Place the same stomp after the amp block and then when you play with the sens settings the distortion will increase and decrease with the sens values.

This makes sense too, as sens is listed simply as the level balance between distorted and clean settings on the amp block. If clean sens actually modified the input gain then the amp would become dirtier the higher it got, the same as with a real amp. The same as if you raise or lower your volume pot on your guitar. It doesn't. Instead you get a clear blend between two signals clean and distorted if you raise it too high. It's sort of a parallel path behavior.

Hey there, yup I check out your files. Actually I should clarify. input sens modifies the output volume/clean blend for the amp block. You can see the methodology I used to determine this in post 16 of that thread.

If you have any effects after the amp block they will be affected by input sens settings. Check what’s there on this rig.

Here, I did a bunch of tests and experiments in this thread a gear or two back What are your ideal settings?

You adjust the volume pot on your guitar.

Try what I suggested. Just because these settings are in the input section doesn’t mean they actually affect the input.

I absolutely disagree with the manual on the clipping, again experimentation will show you exactly what the effect is. It certainly will “thicken” the tone, but not in a good way. Try just raising the output volume on the same rigs to see the difference.

I should have added - If you are finding clean sens is thickening up the distorted tone it is because you are adding hard clipping to the output. This at lower levels this seems to thicken the tone because it’s introducing smaller quantities of aliasing harmonics, these can be any frequencies at all rather than the usual even/odd. The more hard clipping that occurs though the more fizzy or rather fuzzy the tone becomes until eventually it breaks down completely. I believe this is often the “characteristic Kemper tone” that some people complain about or “sameness” and is to me purely user error.

Basically Kemper output is hard clipped. Surprisingly the input seems much more forgiving.

From everything I’ve tested clean sens is output only. It just affects the level of the amp output when the gain dial is lowered. Thus it allows you to control the balance of volume between gain settings to overcome the amp getting quieter as gain is lowered.

You can test this by placing a distortion stomp in line and seeing whether it reacts (cleans up or not) as you adjust clean sens. It will not

Distortion sens meanwhile also doesn’t affect input volumes, even though you might think it does because it lowers the distortion instead it’s actually simply modifying the gain level of the amp. You can likewise test this with stomps seeing what is affected and where.

What I have noticed with the Kemper is that any clipping at all, no matter how small will result in nasty digital clipping artifacts. It has no “soft clipping”. If you want to accurately represent a profile you need to make sure that most importantly your output LED never ever touches yellow. Green and bright green is as far as it should ever go. Yellow indicates that some clipping is occurring, red means more than a certain percentage of the waveform is being clipped (maybe 50%? Not sure how much but enough to devastate the tone). Anyhow, in general I have clean sens set to bare minimum to avoid the fizzy distortion effect, but keep volume even-ish between clean and dirty settings.

Bear in mind that even though clean sens is in the input section it actually applies to the output volume! Therefore keep an eye on the output led in a rig when adjusting this parameter, you do not want any yellow or red there as this means hard clipping is occurring.

Great job, you’re really nailing these!

Well done, who doesn’t love some Crowded House? Good job on his arrangement.

Quote from Calaban

That sounds like there is no cab.

Pretty awful.

He said he did all the checks on whether the cab section was locked, the cab output was disabled etc that I mentioned in a previous post.

Quote from Terence T

Done all the above Per, but thanks for the suggestions. No active pickups.

Didn't buy it to profile my own amp, but to get profiles of amps I don't have access to.

Hi, the point about profiling your own amp is twofold.

Firstly yes it’s what the Kemper was designed for. You get a nice tone that you like the way you like it and then capture it so you don’t have to deal with the issues of recreating it live or for going back to do redo dubs, or just for archival purposes so that you can reuse that tone without waking the neighbors.

But secondly and more importantly in your case so that you can compare and see that the Kemper really isn’t like a Line6 Pod, but is actually very accurate to the source.

Until you do a profile yourself you will never know how accurate it is and therefore you may jump to erroneous conclusions about things like “digital fizz” and so on, based purely on assumption and prejudice.

I know this from first hand experience myself. Knowing that the Kemper is accurate and is a professional tool allowed me to both relax and also helped me train my ear for recording far better than before. I am now able to pick better profiles for my mixes from the exchange, know when and where I might use a real amp instead (and exactly why, and it’s not digital fizz or anything like that, but rather when I want specific room reverb, both power and preamp distortion and when I want to use highly colored mic preamps). It allows me to trouble shoot with a much higher degree of accuracy what is wrong with my signal chain.

I suggest you try it, learning how to profile also brings a new edge to knowledge on micing up your amps, using your signal chain efficiently and effectively.

Most importantly it will clarify for you whether there is a problem with your specific Kemper, whether the Kemper itself is accurate or digital sounding and whether it’s tolerances are acceptable to you. It is the only way to determine this for yourself.