Speaker decoupling refers to the process of decoupling a speaker from its substrate to reduce unwanted vibration or resonance to the floor.
Most speakers generate sound waves by setting in motion a diaphragm that creates sound waves in the air. However, if the speaker is placed directly on a desk or shelf, the vibrations from the diaphragm can cause the desk or shelf to vibrate as well, distorting the sound.
To avoid this, speakers can be placed on special decoupling feet or mounts that act as insulators between the speaker and the surface on which it is placed. These decouplers can be made of materials such as rubber, foam or sorbothane, which can absorb and minimise vibrations.