The Fractal I bought (Axe FX III Mk II Turbo) is a rack unit and is similar to any other tube preamp (e.g., ADA MP-1, JMP-1, Bogner Fish, etc.) in the way it physically operates. You plug into the guitar input on the front of it. There are many options to get the sound out on the back: 1/4" balanced, XLR, USB, etc. There is also an optional foot controller that I purchased, which allows you to change everything with your feet and even plug in expression pedals for wah and volume.
The way I am running it is stereo out into an FRFR (Full Rage, Flat Response) speaker cabinet. These are different from guitar cabinets; they are more like PA speakers. They produce the full 20-20k frequency response without any EQ or coloring, just like a PA speaker would. (This is the opposite of guitar speakers which only produce a very limited frequency range of around 70-6k, and are deliberately EQ'd/colored.) There are a lot of FRFR speakers on the market. Some look more like PA speakers and some look more like guitar cabinets. I have the Mission Gemini 2x12
(specs here) that is and FRFR cabinet designed purposely to look and feel more like a guitar cabinet. It has a built in 220w solid state stereo power amp and is plenty loud. It also has an knob on the back called the "EmPower" knob that makes the cabinet sound, feel, and respond more like a guitar cabinet. You can just roll in as much of it as you want. All the way down is fully flat FRFR and all the way up is 70-6k like a guitar cabinet. I tend to leave it at around 10:00, so it's mostly in FRFR but has a little guitar speaker "flavor." However, I have noticed it's very useful as you turn the volume up: it cuts out the very hissy and noisy upper frequencies that we aren't used to being replicated when we have a loud amp and giant cabinet in the room. So my rule is: as volume goes up, EmPower knob also goes up.
That said, you can run this unit many other ways. You can run it right into your mixing desk and do recording with it. You can run it into your audio interface and get the sound into your DAW. (I believe it even has a built-in audio interface!) You can even forget the modeling and just use it as an effects unit with a regular tube amp, which many pros do.
This is the first modeler I've messed around with since the mid-2010's and I have to say, they have come a LONG way. They used to sound pretty good, but didn't feel or respond like a tube amp; especially if you were a player that uses their volume and tone knobs a lot. Those days are gone. The Fractal responds 99% just like my tube amps when I compare them side by side. They're responsive to pickup output and picking dynamics now, and even get the little things right like the transients when you dig in with the pick on an old Marshall model. Like I said, I'm not getting rid of my tube amps but I'm pretty impressed. I think the fact that artists who previously refused to use modelers are now using them -- like John Mayer -- goes to show you how far they've come. I'd recommend getting one!
