Fractal has said they used 6 mics to make those IRs.
- We already know the "dynamic" option is a SM57, but they had a SM7 mic as well.
- That means the other 4 are likely to be two ribbon and two condenser mics.
- Royer 121 and Beyerdynamic M160 are likely candidates for ribbons, though I wish they used the Shure KSM 313 because that sounds great on some of the Fractal factory IRs.
- For condensers Neumann 184 and/or Audio Technica AT4047 seem likely, possibly an AKG C414 as that was used on some of the factory IRs.
Fractal says that along with the 25 cabs in the beta, they plan to add about a dozen more.
That means that either:
- They need more work to release more mics for each cab and now want to just release all the cabs with a limited set of mics to get the feature out.
- There's a memory/storage constraint that prevents more mics. Fractal would want to allocate some space for future cabs, 3rd party Dyna-cabs etc so that space might be better left available by not having as many mic options on the factory cabs.
After trying the feature yesterday, IMO 3 mics is more than enough. Most users are not particularly picky about the specific mic model but would be interested in the character differences between the mic types and the 3 mics cover that very well, giving you plenty of options to set up the mics to complement each other.