Select all that apply.

A. Smaller halls are better able to reflect bass notes from the side walls and the ceiling, which is an important factor in the quality of symphony sound. B. Old halls are a part of history and heritage, so people think they sound better. C. Old concert halls with good acoustics tend to get maintained and preserved, while ones with suboptimal acoustics get renovated or replaced. D. The atmosphere is more intimate in an older concert hall—visually as well as acoustically—because the concertgoer is relatively close to the musicians.