How should I mike a classroom for distance learning?
Reply: In general, use enough mics so that no mic is farther than 4 feet from a person speaking. At greater distances, the sound starts to get muddy (reverberant) and the gain -before-feedback becomes poor.
If the ceiling is higher than 8 feet, you might need to use hanging mics (Crown CM-30 or CM-31). Hang the mics about 8 feet above the floor. If students are seated at tables, you could use a PCC-170 mic or LM-201 mic at each table.
Run all the mics into an automatic (gated) mixer so that only one mic is on at a time. The Shure SCM810 is a popular automatic mixer.