Could you elaborate a bit further on the concept?
The Kemper is so wrapped in mysteries...
I've been told that it isn't a simple impulse response system.
The Kemper can profile without a microphone though, can't it? Like you can profile just a cabinet.
I've never actually profiled my amps ... I just bought it so I could download everyone else's profiles.... I figure it's a task best left to the professionals
So you need to get your guitar, amp, cab sounding like you want it, then put your appropriate mic in an appropriate place to get the appropriate recorded sound you want. No good getting a masterful creamy distortion from the amp if your mic isn't positioned well to capture it - so you need to know what a good mic'd sound sounds like, and unless you're really experienced, be monitoring it through your recording system (for recording profiles, anyway).
Then you switch over your mic to the Kemper and your guitar lead to the Kemper and set it to profile. The Kemper sends some strange bunch of tones to the amp and the mic picks it up and funnels it back. Takes about a minute. You then have the option of refining it more by playing a few things via the guitar, if you think it needs it.
Voila, you've created a profile. There are many, many people out there who'll tell you it's completely indistinguishable from the amp sound.
And you can now tailor it via the Kemper device in the same way as you would with your amp... bass, gain, volume, presence... add FX if you like, and a heap more arcane functions such as "tube sag" which I don't really understand. And it reacts pretty much the same way as an amp does when you twiddle the physical knobs. Amazing device for people like me who live in apartments and who just can't crank amps to get good sounds, much as we'd like to.
Your profile is specific to a few things though... all the freebie ones you can get will tell you the amp (you have to decode the names because everyone's afraid of saying "It's a Marshall" for some reason), mic, cab and type of guitar pickup - single coil / humbucker etc. Playing the right guitar with the right pickups for the profile makes a huge difference.
The trick, so far as I've discovered in recording, is knowing what you want. There's a shitload of profiles out there, and some of them are very bad. It's fun sifting through some of these boutique amps though, but ultimately if you don't know the sound you want to hear and what amp makes that sound, you'll spend a lot of time scrolling through stuff to no advantage. I'm starting to mark the ones I like and delete from the machine the ones I'll never use, to speed the process up.
It's a complicated machine and I'm not sure, unless I had a full time guitar tech, I'd ever use it live... but people do... As a recording tool, however, in my situation, it's a goddamn miracle...
If you're an undecisive mofo who loves noodling endlessly and experimenting with thousands of different amps and guitar tones, then you'll never finish another song.
Discipline is required.