The Adobe Connect Hub recently posted an entry which lists large lecture rooms where it is known that Adobe Connect will work well at http://meeting.psu.edu/node/591.
All the rooms have a hard wired Internet connection, usually at the podium. This is what allows audio recording to be at the highest quality. They also recommend a stand alone mike also attached to the computer at the podium.
They make addiitonal recommendations on models and what to do if a second moderator is there.