The "Helix Challenge" -- perhaps a bit of perspective is in order, here.

Quote from paults

To me, "Feel" is a very real thing. It is the way a piece of gear responds to playing dynamics. Most modelers I have owned had a more compressed dynamic and tonal range than a good amp. Many of them did this to the point of making all guitars sound more alike.

If an amp is miced in another room, and you are listening to it through studio monitors, the amp still responds to the way you play, and you can hear the changes.

Come to think of it, that is exactly how I compared the KPA to real amps when I first got it.

I'm so glad Paul wrote a post wher I simply need to add a +1.

Quote from Tritium

Indeed. That is what I was trying to convey in my prior post(s), and impart how the "Helix Challenge" is not even in the same universe as the "Kemper Challenge". However, the discussion seemed to veer back to the simple listening to the playback of previously recorded tone.

For instance, I don't even understand MadH's reply...meaning no disrespect:

I will rephrase it. Let say you record a dry clip from your guitar and then you feed the amp and a modeller with that clip. This is done so if there is any difference in sound it cannot be attributed to the player playing differently.

Then you listen to the resulting clips, both the one from the amp and the modeller. If they sound pretty much identical, in my opinion that means that the feel and response produced by the amp and the modeller must be pretty much identical as well. This is what Line 6 is trying to demonstrate.