There are several comments on this subject in Main Manual. Just search for "merged".
studio profiles have the cab and mic "baked" in. better for studio monitors. Merged have the cab and mic separated, meaning you can load a different cab/speaker or Impulse response as they are called, used mostly for frfr or real guitar cab/speakers plus you can turn the cab "off" when using real guitar speakers. I use merged and DI for real guitar cab and speakers.
Quoted from Tritium from 2017. ---------
The question you have asked can be answered by reading the KPA's "Deeper View & Reference Manual"...in particular, pages 28 thru 33, and can be downloaded here:
https://www.kemper-amps.com/downloads/5/User-Manuals
Seriously, read the manual, there is a wealth of excellent information and you will learn so much about the features and capabilities of your KPA, and how to get the most out of your profiling amp. 
However, to answer your question directly, here is something I wrote up for an earlier thread with a similar topic:
------------------------------------------------------
There are three (3) basic types of profiles.
A) Studio -- This is the "normal" profile, and represents the vast majority of all the profiles out in the wild (including factory, commercial, and free). The Studio profile is a combination of the Amp and the Cabinet. In order to be able to switch (or remove) the Cabinet, the KPA has to figure out what contribution the "Cabinet" makes to the profile. To do this, the KPA employs an intelligent algorithm, called Cab Driver, which calculates and determines best approximation in order to separate the Cabinet from the Amp. It works amazingly well. However, Kemper saw opportunity to create a perfect separation, which leads us to Direct/Merged profiles, discussed next.
B) Direct Amp -- This is a profile process that employs a suitable DI box. The DI box takes the signal from the speaker output of the Amp, and sends an XLR/line level signal to the Return Input on the Kemper for the profile process. The DI box needs to have a speaker thru connection which sends the amp's high voltage/high wattage speaker level signal on to the connected guitar cabinet (a tube amp needs to be connected to a load). There is no microphone connected to the KPA during the Direct Amp profiling process.
C) Merged -- This requires a secondary step, after the Direct Amp profiling process. Immediately after capturing the Direct Amp profile, and without making any changes to the amp settings, a normal "Studio" profile is made. The KPA now has data from just the amp (Direct amp profile), as well as the combination Amp + Cab from the Studio profile. The person making the profile (i.e., the original author) then uses the MERGE function, and Merges the Direct and Studio profiles. This is now a Merged profile, which allows the KPA to perfectly separate and subtract the Cab part of the profile from the Amp. Obviously, if the person making the profile only wants the Direct Amp (no cabinet), then the second step and subsequent Merge procedure is not applicable.
-----------------------------------------
-----------
I wonder why commercial profile makers don't sell more merged profiles. Is the benefit not that great ?
I wonder why commercial profile makers don't sell more merged profiles. Is the benefit not that great ?
Many do include Merged versions but obviously they take more time and are only for a specific use case for when people run Cabs live but take a direct out. Even then you can approximate it with the monitor cab button.
More flex but a limited use case.
It has been said: If you monitor full-range (headphones, in-ear, studio monitors, stage wedges, PA, home entertainment,....), there is no sound difference between Studio and Merged. So, you just don't need to care.
It only matters, if you use Monitor Cab. Off to suppress the cabinet simulation at the MONITOR OUT to run a physical guitar cabinet. For that application Merged delivers a more authentic amp simulation than Studio. However, "more authentic" doesn't neccessarily mean that you must like it better.
It has been said: If you monitor full-range (headphones, in-ear, studio monitors, stage wedges, PA, home entertainment,....), there is no sound difference between Studio and Merged. So, you just don't need to care.
I understand that there is no benefit for full-range users.
But there is no drawback for those users either, and it's supposed to be "more authentic" for cab users.
So this should be in theory the universal, always chosen solution.
But obviously this is not the case so there should be another technical reason for the paying profiles to be so rarely merged.
I suspect that the results don't meet the promises.
"more authentic" doesn't necessarily mean that you must like it better.
Or that it sounds better. Just different. I've played horrible direct amps with my guitar cab and have produced great tones using cabdriver.
I understand the process but want to ask, when using a merged profile, I imagine it is "split" so that only the direct sound comes from the power amp /monitor out, and the Amp + cab+ mic (studio profile) goes to the main outputs like normal right? So using a merged profile should be exactly like a studio profile when monitored through the main outs because the only difference is a merged profile includes an extra component, a direct sound that can go to a regular cab.
Since it is merged into one, how does the Kemper split it up the way it was profiled? Sounds like what cabdriver does.
As said before, the overall sound (amp + cab incl. microphone) of Merged and Studio is identical. For any full-range monitoring the difference is irrelevant. Only driving a physical guitar cabinet at the MONITOR OUT (or SPEAKER OUT of powered models) with Monitor Cab. Off activated it matters. In that case Merged is more authentic - closer to the original amp. But sometimes users of that specific application like the less authentic approximated sound of a Studio PROFILE provided by CabDriver better. Decide with your ears!
Personally, I like merged profile because I like to use the same cab for all my rigs (I don't use more than 5) and keep a sound consistency during a show.
My ears need adaptation time to switch from a cab to another.
Personally, I like merged profile because I like to use the same cab for all my rigs (I don't use more than 5) and keep a sound consistency during a show.
My ears need adaptation time to switch from a cab to another.
I think, this is a completely unrelated subject.
You can lock a cabinet or store it as a cabinet preset or use selective browse to combine it with various amps picked from other Rigs regardless, if these are Merged or Studio PROFILEs.
If you check Rigs provided by Michael Britt you will notice that he is basically reusing two cabinets all the time. Similar applies to Bert Meulendijk, who is also reusing just a handfull of cabs. Selecting Rigs from one of those guys could therefor be an excellent starting point to stick to one cabinet.
I don't understand how this preference to stick to one cabinet is related to Merged versus Studio. Or what is it exactly, that you think cannot be done with Studio?
I agree, it's off topic.
In my mind I applied the same reflection of using a real cab. I thought using merged profiles gives a more accurate result than studio if I always use the same cab or ir.
I agree, it's off topic.
In my mind I applied the same reflection of using a real cab. I thought using merged profiles gives a more accurate result than studio if I always use the same cab or ir.
I think I understand what you are saying that a direct amp sound into an IR would be more accurate as far as what the IR is getting. A studio profile would have to use cabdriver to remove the cab, so you can add one again.
I once tried direct amp into some cabs I have in amplitude and guitar rig and it was immediately apparent that the extra step wasn't worth it using that method. The Kemper does just fine on it's own and it's easy to lock cabs and find the one that works for you if you prefer the one cab route.
