I hear little sound differences on all Kemper vs. Real amps tests.
There certainly is a difference in the tone and it can be easily scientifically proven by simply looking at the waveforms and basic spectrum meters.
I don't mean to bash the master here but the tweaked version of Andy Sneap's profile had less 80hz, more 200hz, less 400hz, more 850hz but after that the profile was spot on spectrum-wise. No I couldn't tell the diffence in a mix.
The Kemper doesn't capture an amps tube dynamics. It has tube-like dynamics, but it doesn't capture the exact tube dynamics of your amp. The difference might not be like night and day maybe but more like "is my microphone slightly off?". I've been getting crap from Kemper users ever since I made my review where I was unhappy with the profiling accuracy.
What I noticed in the long run was that Kemper has problems capturing 125hz. On some profiles there was too little of it and on some profiles there was too much of it. The higher presence area has some clear aliasing going on also. It sounds like a compressed mp3 quality in certain aspects to me at least.
My whole point is that I think Kemper is overpriced. "Wow it steals your amp's sound" wasn't a big factor for me since I've done it for years with Ozone that only costs 200. The only difference is 1) I have to find the amp drive level manually and 2) when Ozone is complete, I don't have to do ANYTHING to make it sound unnoticably similar in a mix. I can give you guys a clip if you want it.... hell.. I'll give you my guitar stems and I bet no one can tell where it's the real amp and when it's Ozone:
This is an old raw mix of the song:
Guitar stem:
I'll hammer my Axe-Fx Ultra to tiny pieces if someone can point out the two parts in that song that are not the real amp.
This is not about who you should trust: Andy Sneap; a professional audio engineer or Clark Kent; the 25 year old guitar geek. That's not what this is about and I don't get why that's the way people see it. Both Andy and I have said that the profile was not 100% there. Andy is able to live with it and tweak it to where he's happy with it. I'm not willing to tweak it since I know I can get there easier with different techniques and therefore am not able to live with it.