TOPIC:

Could I use my EARS rig to measure loudspeakers, subwoofers and acoustics? Or do I need the UMIK-1 for that? If I were to use the EARS, which compensation file would be the most accurate for the job?

If you want to make a room measurement use a UMIK-1.
Ears are really meant to be used for "headphone" measurement. That's how we calibrated the unit.

DevTeam

I use hears for speaker room correction too because the hears shape filter room reflections with simular directivity as real ears do and i get much better sound results now what i hear and in compare to headphone. I have no omnidirectional ears. I have no good room it is L size and under the roof. I use basstraps but all damping does not change FR.  btw my measure explain wy target curves with reduce high freq are used. with omni microphone there see only 2 large room modes at 88 hz and 160 hz all other look nice. so everybody assume reduce this nodes by around 8 db and you get a good linear sound. but thats wrong and work not in my room. reduce high with a target curve also make not better sound. the minidsp hears show the true. the mids need boost . I need not reduce the room modes a EQ 700 hz q 0.5 3 db and i get amazing sound very simular to headphone. also the gap at 5.3 khz that hears show is true. because it sound even more simular when i boost this with Q 4 2.5 db. I use the HPT cal file . maybe a omnidirectional microphone make not much diffrence when have a good room, but for bad rooms it give better results when use a microphone that have directivity of ears to see the problems the ear shape do together with the room. see screenshot of measure with omnidirectional microphone and hears