A room with soft furnishings produces fewer echoes than an empty room with bare walls.

The longer version

Porous materials such as fabric, carpet and padding let air move into countless tiny gaps, where friction turns organised vibration into a trace of heat. Very little energy comes back out, so a room filled with soft objects has a short decay time and feels dry and close. Absorption works best where the material is thick compared with the wavelength involved.

Bare plaster, glass and concrete are dense and non-porous, so they bounce most of the energy and let it slosh around for a second or more. Recordists judge a space by clapping once and timing how long the tail lingers. The same is why an unfurnished flat seems harsh until furniture arrives.

Where this entry sits

Sound and Music gathers facts about how vibrations move through air and water, how ears turn them into meaning, and how instruments and notation shape what listeners hear. Expect echoes, pitch, volume, acoustics, and the odd silence in between. The full list sits on the Sound and Music page, where every entry is listed in order.