when close miking as typical in the studio (or bedroom) we ARE less than a foot away. The same happens with clip ons. Omnis are a non issue in the brass world - feedback on stage as well as too much surrounding noise. 30 to 50 feet gives a very nice perspective as well as a "feel" for the room. It is also far enough that the directional qualities of the trumpet do not cause sound issues with the recording. The LF roll off of the mike does not solve the tubbiness. I don't know of any decent stage work or recordings made without EQ.