In our mind's eye, we conceive the existence of a third dimension. My guess is that hearing is essentially a 1-D system of perception. Answering the first question is not as simple as quizzing a blind person. Secondly, although blind persons may have heightened hearing with respect of seeing persons, I doubt that any use hearing as their principal means of sensing spatial dimensions. To answer the first question, we need to know the mind of a sentient being which uses its hearing as the principal spatial sensor.
Bats perform amazing spatial maneuvers using sonar.
Unfortunately, it is hard to believe that bats are sentient. Porpoises and whales, on the other hand, probably have some degree of self-conception and may rely upon sonar as their principal spatial sensor. Perhaps we may legitimately ask how many spatial dimensions does a porpoise conceive the universe possesses. Research in communication with porpoises has been conducted for at least several decades now. In our intellect, before we developed writing but after we developed language, we used sight as our principal environmental sensor and hearing for communication.