Be aware of the digital sonic artifacts (aliasing) in your KPA!

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Radley

Professional

Posts: 617

Location: So Cal

101

Thursday, May 24th 2012, 3:59am

And these types of responses are what make some of us crazy - this is very easily identified to experienced ears as classic digital aliasing, and it has nothing to do with pickups, or other factors but is a very natural product of sub-par digital processing (we're talking 2012 folks).

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Per

Professional

Posts: 612

102

Thursday, May 24th 2012, 6:46am

I realize it's frustrating, but a guitar note through an amp is a very complex thing with many sounds, harmonics and what could be perceived as undesirable artifacts, so in order to "hear" what it is you're hearing requires first eliminating everything else first.

So to that end, are the ghost notes in this what you're talking about? (you can hear it mostly around the 17th fret in passing but it's elsewhere too) sounds a little like a ballbearing rolling accross a board in the bg : http://www.per-anders.net/general/ghostnotes01.aif (two different settings).

Or are we talking about a phasing sound? Or the bloom in the earlier example, or something else? I don't necessarily have the most sensitive ears, but I would like to help you and Kemper find the solution.

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Kermit

Beginner

Posts: 31

103

Thursday, May 24th 2012, 11:09am

Quoted from "Radley"

And these types of responses are what make some of us crazy - this is very easily identified to experienced ears as classic digital aliasing, and it has nothing to do with pickups, or other factors but is a very natural product of sub-par digital processing (we're talking 2012 folks).

Every week pops up a new topic in this forum that something is wrong with the higher notes played by the KPA.
But none of this threads has a proof (pardon me if there is proof I have overseen)
I do not own a tube amp so I'm not able to prove something is wrong with the KPA.

So Radley you have a tube amp, a microphone and a computer to record?
Then profile your tube-amp
Record a dry guitar track with those high notes
Reamp it with your tube-amp
Reamp it with your KPA
Check for differences

All other discussion is pointless

This post has been edited 1 times, last edit by "Kermit" (May 24th 2012, 11:20am)

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professortweed

Intermediate

Posts: 200

104

Thursday, May 24th 2012, 12:17pm

Doesn't seem to be a problem on the amp block for Radley - post 83. I haven't heard it yet but I only use the stack block - no stomps, no fx, and no noise gate.

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Kermit

Beginner

Posts: 31

105

Thursday, May 24th 2012, 1:55pm

It is little bit confusing to have so many isseus in just one thread.
I use only the TS stomp box in the KPA and I have no problems at all.
@Radley
You can also profile your high-gain stomp box if the build in stomp box has aliasing. Does this work?
Your noise problem is probably self-made because of the complexity of your chain within the Kemper:
You use a Compressor + High-Gain Stomp + High-Gain amp + NR and complaining about too much noise?
Maybe this works in an Axe Fx but not in the Kemper.
I have played with many modelling amps in my life and they all have things that don't work when it
comes to complex chains and too much gain.
There are also a few profiles with a high noise level which could make things even worse.
But in general the KPA has not more background noise than other modelling amps.
And High-Gain Tube amps have even more noise issues.

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miles

Trainee

Posts: 131

106

Thursday, May 24th 2012, 4:22pm

Quoted from "Kermit"

It is little bit confusing to have so many isseus in just one thread.
I use only the TS stomp box in the KPA and I have no problems at all.
@Radley
You can also profile your high-gain stomp box if the build in stomp box has aliasing. Does this work?
Your noise problem is probably self-made because of the complexity of your chain within the Kemper:
You use a Compressor + High-Gain Stomp + High-Gain amp + NR and complaining about too much noise?
Maybe this works in an Axe Fx but not in the Kemper.
I have played with many modelling amps in my life and they all have things that don't work when it
comes to complex chains and too much gain.
There are also a few profiles with a high noise level which could make things even worse.
But in general the KPA has not more background noise than other modelling amps.
And High-Gain Tube amps have even more noise issues.

Kemper has acknowledged to me that they are aware of the exact problem I posed at the beginning of this thread, and says they are planning a fix in firmware. Radley is right when he said "this is very easily identified to experienced ears as classic digital aliasing".

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schneidas

Master

Posts: 1,834

Location: Athens, Greece

107

Thursday, May 24th 2012, 4:27pm

Quoted from "miles"

Kemper has acknowledged to me that they are aware of the exact problem I posed at the beginning of this thread, and says they are planning a fix in firmware. Radley is right when he said "this is very easily identified to experienced ears as classic digital aliasing".

Did you get any update on this from Kemper in the meantime?

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