There are many differences in the acoustical properties of buildings or rooms. Some are quiet enough to hear a pin drop from one end to the other. In others, you almost have to shout to be heard barely across the room. Still others are noisy and filled with echos. There are many factors that determine the acoustical properties of buildings or rooms within buildings.
Large buildings have different acoustical properties than small ones because of echos. Sounds made in any building echo off walls, ceilings and floors, but the echo comes so quick, you can't differentiate the echo noise from the original noise. Sounds made in a large building such as a gymnasium, are heard much differently because there's enough time lag to allow you to hear the original sound and the echos.
The materials from which the floors, walls and ceilings of a building are constructed or covered have a great deal to do with the acoustics. Hard surfaces such as brick, concrete and wood reflect sound waves. Soft surfaces such as carpets, foam insulation or draped windows absorb sound waves, diminishing echo effects. If you are building a sound studio or other building where acoustic properties are very important, consider using acoustical foam panels to soak up the sounds.
The shape of a building influences acoustics. Some shapes scatter the sound waves that strike them; other shapes direct or concentrate the sounds. Buildings in which the acoustic properties are of little significance tend to be square for utilitarian purposes, or designed strictly for appearance. Buildings such as orchestra halls or theaters are designed to enhance their acoustics.
A big, empty building has drastically different acoustics than a big building filled with furniture, people, cargo or other items. The contents both absorb some of the sound waves inside the building, and randomly deflect the sounds around the building.