Cabs and user IRs
What an impulse response is, how one gets onto the FM3, 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
Factory cabs covering everything the Axe-Fx III has, and 1,024 memory locations for your own, held in a single bank.
FM3 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 — Manage Cabs
Drag and drop user cab files into memory slots, and manage what is already there. Don't forget to press Save.
- 2
Or Fractal-Bot, for one at a time
Set the Cab block to the slot you want to fill, then send the .syx to the unit and it stores it there.
- 3
Then point the Cab block at it
Select the Cab block and change it to the bank and number you transmitted to.
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 back up as their own bank of 1,024
One more file in the backup set, separate from your presets and from SYSTEM. A restore without it leaves presets pointing at cabs that are not there.
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.
There is an Erase All User Cabs option
It clears every user cab, leaving them all EMPTY, and asks you to confirm first. Have the bank backup before you use it.