Hi All,
Thanks for letting me be a part of your community for so many years.
This thread will share some of the knowledge I've gained through my years in as a recording engineer and as a tinkerer with both the Axe-FX II and the Axe-FX III in order to get the most out of the unit for bass playing.
Here's a Google spreadsheet that I'm sharing as I'm updating bass presets to Cygnus to help dispel the widespread opinion that there are only 6 bass amps in the unit. If you make a little bit of an effort, you will find that you can find a world of bass tones and effects in this unit if you use your ears and alter some setting, just like you did on your real bass rig (no one just hooks into the amp without making some parameter tweaks to an amp).
Some caveats:
Just as all guitar amp sims do not play well with all guitar cab IR files, the same holds true for adapting amp models to bass.
The tonality of a particular amp model working for you depends upon a variety of factors:
Type of instrument
Type of pickups
Type of strings
Finger or Pick technique
String type and gauge
Playing style
Musical genre
Amount of gain used
Types of effects used
Instrumentation accompaniment
Musical arrangement
Speakers loaded in Cab captured as IR files
Mics used in IR capture (the EQ curves between mics make a huge difference to whether a cab is workable or not for the amp model)
Position of mic used in IR capture (some speakers really get dull at the edge position, some can floss your teeth in the cap position)
Design of the Cab
Monitoring volume
Type of monitoring used
Acoustical properties of your monitoring environment
I'm not including the bass amps in this list as most Fractal bass players have probably thoroughly explored those models already.
If you need to clean up some frequencies that bug you, use the 5 band Passive EQ in the amp block post power amp and BMT (don't be afraid to get aggressive with the controls).
All evaluations are based upon Cygnus FW16.00 and later.
As I go through updating presets to Cygnus, I will be updating the list.
Feedback is always appreciated as long as you are civil.