Rooms that have unfavorable acoustic properties can often be improved through the use of well placed electronic audio systems. Likewise, even good auditoriums can often have their acoustic properties improved by the same means.
Various loudspeaker shapes have different directivity patterns.
A vertical column of speakers produces a radial beam which spreads out much more in the horizontal direction than the vertical direction. This increases the effective while maintaining a broad distribution in the horizontal direction.
Horns usually have greater radiation efficiency than cone-type speakers, though their low-frequency response is usually weaker.
A frequency-dependent electronic (or mechanical) reverberation system can be used to provide ``resonance'' to an otherwise dull room. Also, such a system can be used to vary the reverberation characteristic to best match the particular use of the room.