Kemper Amps Forum

Quoted from "miles"

Quoted from "ckemper"

Quoted from "miles"

Quoted from "ckemper"

It's dependent in the gain. The amp allows much more gain than the stomps, and more gain than most tube amps. Where is your gain set to?

I have noticed the aliasing in the higher note register with nearly the entire range of gain in the KPA, from low to high from any profile, by any author. I have been profiling for the last several days, and when I A/B my source amp and KPA profile, it's very evident. Even if the aliasing is not jumping out at you, it kind of floats around in the background, almost subliminally.
I imagine that the sine sweep test by dhodgson would have likely demonstrated the noise with almost any amount of gain.

No, by physics the distortion aliasing level is a function of gain.
Hodgsons sine sweeps were high gain only.
I can easily create noticable aliasing on many modelers with sine sweeps.

Some stated to hear aliasing with clean guitar sounds. Yet to be demonstrated.

Here are sound files that that I made that demonstrate the digital artifacts in clean sounds that I mentioned earlier, and there are 2 to consider here:
I made these files by profiling a Grace M101 mic pre DI. The first file (Grace-KPA Clean Test 1) has two groups of high descending notes; I am A/B-ing the Reference amp, and Kemper amp straight to ProTools via the KPA's analog outs. The first group of notes are the Reference amp, and are very clear, the second group are from the Kemper amp, and to me it sounds similar to what I hear in the high gain aliasing... though how could that be? Perhaps it's more of the "burst" effect than the "wind howling", you be the judge.

Grace-KPA Clean Test 1

The next file (Grace-KPA Clean Test 2) demonstrates what I will refer to here as 'light distortion' on clean sounds. I find this artifact undesirable, and since no one seems to be noticing it, I figured it was time to reveal--it is apparent enough that I intend to refrain from any pure-clean profiling until it's fixed. If it's related to the aliasing, I just don't know.

Grace-KPA Clean Test 2

No stomps were used at all.

How does your guitar sound when played direct without the KPA? (Also does changing the clean sens etc setting or rolling down the volume on your guitar pot help or change things at all?).

On the second one it sounds to me more like soft limit than aliasing.

On the first though sounds more like what's now being described as aliasing, which is a compresison artifact caused by too quick compression attack. Is there any compression in the first rig, or is it just the amp itself?

Quoted from "ckemper"

We have actually found a flaw in 1.09 that causes loud aliasing in the amp at high gain settings. We will have an alternative 1.09 soon.

Thanks!

CK

very good news!

Quoted from "ckemper"

Today, 6:17am
We have actually found a flaw in 1.09 that causes loud aliasing in the amp at high gain settings. We will have an alternative 1.09 soon.
Thanks!
CK

Below is a quote from the "FW. 1.0.9" thread, which states this newer 1.0.9 version addresses a "stability issue".
So, I am guessing there will be yet another 1.0.9 version, that CK refers to in his quote above. Yes/No?

Quoted from "G String"

Today, 12:33pm
We've released a new public beta for version 1.0.9 just now.
The new version is called 1.0.9.7426 - It is identical to version 7415 but addresses a stability issue introduced in the first release of 1.0.9

have a good weekend, gs

Quoted from "miles"

Quoted from "MadH"

Quoted from "miles"

MadH,
I can't help it if some people can't hear it, it's the ones who can that matter most to me. I'll bet any pro-studio engineer would recognize the artifacts in my sound files.

Sure, I did not mean it that way. It does not matter how many people notice it in order to take action to fix it. I was just pointing out that I thought that a lot of people would not be able to notice it (unless they used proper equipment like you suggested). My first audition of the 1st clip was using computer speakers and even if I noticed something off I could not hear clearly what it was. When I plugged in my studio headphones it was more obvious.

Hey MadH, no sweat, I wasn't referring to you, but rather to the doubters. Peace.

Don't worry . I know you were not referring to me since I said that I could hear the issues demonstrated in your clips.

Quoted from "miles"

Quoted from "and44"

yeah thats easy to spot..when its set out like that. and quite noticable too.
almost seems the profiling has gotton confused, and put a clean signal via a distored gain stage or 2. - (sounds like tubes are broken and on the way out LOL)

What guitar pickups were used for this test? - and do you have any other guitars to test with to see if you get the same level..
as it might just be default gain stage set a bit HOT in the KPA (clutching at straws here)

i just tried this, and dont get that problem, - or maybe its to do with SPDIF traffic? bad cable? interference.. anything.. again not based on fact just trying to eliminate everything possible so we can work towards an exact problem..

Is this test you done noticble while playing pre-record? - or record only?

Are your clean and distortion sensi at low levels? - and did you adjust these and did it make any differnce?

Do you get the same results on every pickup position?

have you tried a differnt guitar cable? and/or SPDIF cable?

if you turn the volume down to half on your guitar does it still appear?

Just tryng to figure out more.. so excuse the random questions...

A

The guitar in the sound file is a Strat with a Duncan Custom bridge pup. I also tested with another Strat with Fralin Split Blade Blues pups and though the noise is less, it's due to the lower output of the single coil, which doesn't solve the problem of wanting to use humbuckers, really clean. I have no doubt that all my guitars and basses will have the same end result.

The noise is nowhere in my recording chain.

Clean and dist sens are both low, but increasing them does seem to bring the noise forward relative to the amount on gain.

Cables not an issue.

One more thing I noticed, when I had the Grace sitting idle, and the KPA in profiling mode, after matching levels between the Grace and KPA, I would A/B back and forth and I could hear the increase of the noise floor of the Kemper amp vs. the Reference amp, but that's to be expected of any digital or analog gear.

Once saved the profile have less noise floor than in profiling mode..but still it's a bit higher than the original..I said that from the beginning and even posted a clip

Quoted from "Jimmyno"

Quoted from "Per"

Unfortunatelyy I've been way too busy to really test the current version beyond checking aliasing for this thread with that one patch , but are you saying the sound has changed? Can CK confirm whether anything has changed that would make it more "liquid" (and therefore in my mind less like the original amps and more like an amp sim)? This is a little worrying.

Don't get me wrong: i feel that the whole has become less spongy and more natural in the attack. I don't know if there's something about the new gate, about latency, about anything different in the algorithm, but i like it more than before.
I cannot exclude that it's just a "120% more real" syndrome

Thanks !
But we have not applied any changes to the core sound engine since the release of the profiler.
Must be your imagination. But it's a good imagination!

In three month or so somebody will say 'I have gone back to 1.09 because the new firmware sounds too fizzy. The old one is much fatter'.

In out sister company Access Music (Virus Synthesizer) we have a 15 years history of compatible sounds. You can load a sound from 1997 into the latest Virus and it'll sound the same.

We have no plans or ideas to improve the core sound engine of the profiler in terms of getting closer to something.
If we ever applied changes to that in the future, we will still make existing profiles and rigs sound the same.

My plan is to let your profiles and rigs sound the same in 15 years, as you have created it today. No matter what hardware, software or firmware you run it on. Of course there will be improvements and paradigm shifts. But no technical innovation can algorithmically improve the sounds that you have created by 20% or whatsoever.
If there is an innovation, you will have to add it to your sound by hand and in purpose.

Of course, if there is noise etc. to reduce, we will try our best. But I don't consider this to be part of the sound.

CK

Awesome, good to know CK, thanks! I'm looking forward to the next 15 years of my KPA then