Cabs and user IRs
What an impulse response is, how one gets onto the Axe-Fx III, and the file extension that looks right and does nothing.
What a User Cab is
An impulse response is a recording of what a mic'd speaker cabinet does to a sound. Someone plays a frequency sweep through a real cab, records the result, and mathematically removes the sweep — what remains is the cabinet's fingerprint, which can then be applied to anything. Fractal call these User Cabs when they are yours and Factory Cabs when they shipped with the unit. They are the same kind of thing.
How much room you have
2,048 factory cabs, and 2,048 more memory slots for your own — plus 16 scratchpad memories for auditioning something before you commit it to a slot. User cabs are held in two banks, and a third bank takes the newer FullRes format, which allows an IR up to 1.37 seconds, longer even than UltraRes.
Axe-Fx III Owner's ManualTwo file extensions, and only one of them loads
An IR you are transmitting to the unit is a MIDI System Exclusive file — .syx. The newer .IR extension is used solely for re-mixing inside Cab-Lab and is not what the hardware takes. Fractal flag this explicitly because a download page will often offer both, they sort next to each other, and the wrong one simply does nothing.
Loading a User Cab
Two routes, and the editor's is much the better one for more than a single file.
- 1
The editor — Axe-Manage Cabs
Drag and drop cab files into memory slots, and manage what is already there: copy, paste, rename, and — unlike the Helix librarian — genuine drag-and-drop reordering. This is the right tool for a Cab Pack, because you can load, audition and organise in one place. Press SAVE when you are done.
- 2
Or Fractal-Bot, for one at a time
Open a Cab block, set Cab 1 to the bank and number you want to fill, then send the .syx from Fractal-Bot and the unit stores it there. Fractal-Bot can also transmit whole banks at once.
- 3
Then point the Cab block at it
Select the Cab block, press EDIT, and change the cab to the bank and number you transmitted to — "USER 1, #215".
Note down the bank and slot as you send
A cab lives at a Bank and a Number — "User 1, #215" — and the Cab block selects it by that address rather than by name. So the number you transmitted to is the number you have to select afterwards, and a preset someone shared expects THEIR slot numbering, not yours. Write it down while you are sending; it is far more annoying to find later.
User cabs are NOT in a System backup
Unlike older Fractal units, the Axe-Fx III keeps user cabs outside the SYSTEM area. That cuts both ways and both are worth knowing: a System backup does not protect your cabs, so back the cab banks up separately — and restoring a System backup will never overwrite them.
Where to get them
Fractal's own shop sells professionally produced Cab Packs, including third-party producers. Axe-Change, their file-sharing site, is a large free library. And the unit has an IR Capture utility if you want to photograph your own cabinet — it needs a mic and a preamp, plus either a flat full-range power amp or a speaker-level DI box.
Cab-Lab is a different tool for a different job
Cab-Lab is an IR mixer — it blends several IRs into one, the way an engineer blends several mics on a real cab. Fractal recommend it for capturing too, because the interface is easier than the on-unit utility. It is not required to load an IR someone else made.
Capture uses Output 2 Left
If you use the built-in IR Capture utility, it sends its sweep from OUTPUT 2 LEFT — so Output 2's "Copy Output 1" has to be set to OFF first, or the capture goes nowhere useful.