$sound diffraction examples$

$sound diffraction examples$

It can be a tricky balance for an acoustic designer – too much absorption, and the room will sound dead. This absorption can be a specialist product such as those made of mineral wool, open cell foam, or recycled fibrous material like paper-waste, but absorption can also be provided by more commonplace object such as curtains, sofas or carpets.

$sound diffraction examples$

One solution to reflections is to apply absorption to the wall, which turns acoustic energy into heat – this is a kind of damping. There are two basic forms of acoustic treatment to deal with reflections: absorption and diffusion. These later reflections all blend in together, and cause reverberation. The higher-order the reflection, the further the wave has travelled and the later they arrive.

$sound diffraction examples$

Second order reflections are like shots played off two cushions, third order off three etc etc. You can imagine the waves bouncing around like balls on a pool table. In small rooms, first order reflections tend to be loud and arrive very soon after the direct sound. The diagram below shows a plan view of a small rectangular room, highlighting a first order (involving only one reflecting surface) reflection from the top wall in red. (Timbre is a French word which describes sound quality). These reflections can cause the sound to be coloured, or to put it another way, the timbre of the sound will change. The direct sound arriving at your ears directly from your hands is quickly followed by reflections from the walls, ceiling and floor. Try this experiment – go into a small bare room like a bathroom and make noise – a handclap will do. Hear the difference between a room with strong reflections and one with no reflections (anechoic chamber)

$sound diffraction examples$

Sound diffraction examples