It's not really any different than setting up everything to record a guitar track. Dial in the amp the way you want it to sound, and experiment with mic placement until it also sounds good to you. The two (tone controls and mic placement) are almost interactive, so it takes a bit of trial and error to get there.
I would also recommend making direct profiles of each amp on the settings that you like. This allows you to keep a raw, preamp sound filed away, so if you ever want to try out a different cab sound, you're only a few taps and turns away from it sounding exactly like it would driving that particular cab.
Here's what I do, hopefully it gives you an idea or two.
I mic a cabinet up in my Live Room. Run a long speaker cable from it to my control room, where the amp is. I tend to hook up at least 4 mics on a cab at a time, and I listen to them through my monitors (KRK VXT6s).
I'll mess with mic placement until I get what I'm looking for and also phase correct them. But the big thing I do is I have my amp in the control room and the cab in another room. Why? Because what I hear off my monitors is what I'm sending the Kemper. I think it's kinda backwards if you're leaving your amp head in the room, tweaking it, coming back into your control room, and having to go back and forth. Just dial in the amp from the control room and have your monitors cranked through your recording/profiling board/setup so it drowns out the leakage from the cranked amp.
I know a lot of people don't have the luxury of two rooms, but it makes it much easier to get a tone that you're looking for if you don't have the profiled cab blaring in the same room you're trying to profile from. in my opinion, other than mic placement and gain staging, this is the most important thing for good profiles. If you can't hear what you're doing / sending to the Kemper, you're really shooting in the dark. Sure you might get some good profiles but it's going to be more of a luck thing than a planned one.
Oh, and take plenty of breaks. Your ears get fried pretty quick especially if you use loud volumes. And if you are going to use your profiles live through a certain type of powered monitor, use that to monitor your Kemper output and dial your amp in for that.
And if you are going to sell the amp you are profiling, profile the hell out of it - different mics, cabs, settings, etc. Make more profiles than you think you'll need because then you'll be covered later. Nothing worse than profiling and selling an amp and then deciding later you didn't get all the profiles you wanted out of it. Don't ask me how I know this. 
Pete
I would also recommend making direct profiles of each amp on the settings that you like. This allows you to keep a raw, preamp sound filed away, so if you ever want to try out a different cab sound, you're only a few taps and turns away from it sounding exactly like it would driving that particular cab.
to clarify, there are two types of direct profiles:
preamp only - these are taken from the send of an amp's fx loop
whole amp + cab and power amp interaction - these are taken from the speaker out of an amp while it is connected to a cabinet (!). Use a DI box that can deal with speaker level signals.
to clarify, there are two types of direct profiles:
preamp only - these are taken from the send of an amp's fx loop
whole amp + cab and power amp interaction - these are taken from the speaker out of an amp while it is connected to a cabinet (!). Use a DI box that can deal with speaker level signals.
I wanted to ask this for quite a while: the preamp only profile - is ist possible to profile it WITHOUT a DI box?? 
as far as i can understand from the manual: it is not, right?!
I wanted to ask this for quite a while: the preamp only profile - is ist possible to profile it WITHOUT a DI box??
from the manual:
"While it is relatively straightforward to capture Direct Preamp Profiles from line-level outputs of bass amps, or the send outputs of preamps..."
when you are using a line-level send output, there's really no need for a DI box. it's like using the output of a modeler for example.
the amp must still be connected to a cabinet, however.
Am I the only one who is "very sceptical" about the "direct profies";I have the impression(dont know if this is indeed the "problem") that the KPA has not the nescessary DSP power to really separate the preamp/amp/cabinet in a 100% needfull way.I am convinced that "studio profiles" are still the best way to go allthough I have no doubt that the KPA2 some day will allow better separation.
What kind of cables do you use to bridge the long distances from the control room to the recording room;I just ask because I spent some years ago 2000 euros for Sommer-Cables and their Plug-Mama/Pegasus/Spirit etc cables..imo this is very important to do if you want a "good result" and you amp is 10 meters away from the cabinet.
Sorry, it's once again me, but here we have what @DonPetersen mentioned.
While it is relatively straightforward to capture Direct Preamp Profiles from line-level outputs of bass amps, or the send outputs of preamps, capturing them from tube-amps that include the power tube section is a bit more challenging. It requires you to tap the sound where it is about to hit the speaker cabinet. This tap is the speaker out- put, where high voltage and high wattage occur, meaning you will need a dedicated DI box for this purpose. This specialized DI box is capable of scaling down the voltage to a line-level signal, suitable for the Profiler, on a XLR output jack. The high-power signal is forwarded to the speaker cabinet through a different output jack.
I would like to profile my Plexi again which is not possible, because it sounds good only at INSANE volume and i do have neighbours. And i do not want to buy a DI box only to profile ONE amp and then sell it on ebay for half the price. or can you recommend a cheaper solution? I do have - nevertheless - an
ARTcessoires DT Dual Transformer but this will be of no great help here?
Personally I use a Dyson!. the best suction there is!
Sorry, could not resist!.
Sorry, it's once again me, but here we have what @DonPetersen mentioned.
While it is relatively straightforward to capture Direct Preamp Profiles from line-level outputs of bass amps, or the send outputs of preamps, capturing them from tube-amps that include the power tube section is a bit more challenging. It requires you to tap the sound where it is about to hit the speaker cabinet. This tap is the speaker out- put, where high voltage and high wattage occur, meaning you will need a dedicated DI box for this purpose. This specialized DI box is capable of scaling down the voltage to a line-level signal, suitable for the Profiler, on a XLR output jack. The high-power signal is forwarded to the speaker cabinet through a different output jack.
I would like to profile my Plexi again which is not possible, because it sounds good only at INSANE volume and i do have neighbours. And i do not want to buy a DI box only to profile ONE amp and then sell it on ebay for half the price. or can you recommend a cheaper solution? I do have - nevertheless - an
ARTcessoires DT Dual Transformer but this will be of no great help here?
Can't you hire a rehearsal room locally for an hour or two?
Can't you hire a rehearsal room locally for an hour or two?
This exactly the problem. You would not believe how expensive it is here. You wont be able to get access to a room here for just a few hours and if it will cost
easily 50.- Euro. You pay 400.- a month here. I will have to wait until fellow user labrat who has a room returns from sailing in the atlantic.
Am I the only one who is "very sceptical" about the "direct profies";I have the impression(dont know if this is indeed the "problem") that the KPA has not the nescessary DSP power to really separate the preamp/amp/cabinet in a 100% needfull way.I am convinced that "studio profiles" are still the best way to go allthough I have no doubt that the KPA2 some day will allow better separation.
What kind of cables do you use to bridge the long distances from the control room to the recording room;I just ask because I spent some years ago 2000 euros for Sommer-Cables and their Plug-Mama/Pegasus/Spirit etc cables..imo this is very important to do if you want a "good result" and you amp is 10 meters away from the cabinet.
Your speaker cable is important and would need to be good quality, but since it's active/powered it's not as important IMHO as a long guitar cable - I don't think you get as affected by capacitance from cable length in a cable that's carrying an active signal vs a passive one. The guy from Trainwreck amps used to make his own speaker cables out of lamp cord / extension cable wire! By the way, the guys who use the speaker cables that are the same size as a garden hose or are so big the jacks look tiny usually have stock wiring inside the speaker cab - which is usually much smaller than you'd think. Not only that, but the wiring inside your amp from your speaker output jacks is typically fairly narrow too and it goes directly to a transformer on tube amps.
Am I the only one who is "very sceptical" about the "direct profies";I have the impression(dont know if this is indeed the "problem") that the KPA has not the nescessary DSP power to really separate the preamp/amp/cabinet in a 100% needfull way.
Nope. This is an urban myth.
There is no extensive DSP power necessary IMO.
It's simple math, simple subtraction:
Studio profile minus direct amp profile equals the separated cab. 
I would like to profile my Plexi again which is not possible, because it sounds good only at INSANE volume and i do have neighbours. And i do not want to buy a DI box only to profile ONE amp and then sell it on ebay for half the price. or can you recommend a cheaper solution?
A cheaper solution?
Buy the DI box used in the first place.
With a little patience you'll find anything on Ebay.
