A Helmholtz resonator (named after Hermann von Helmholtz) is an acoustic resonator. Laypeople may be familiar with it from everyday life as a bottle that produces a sound when blown into at the neck. Helmholtz developed this resonator in 1859 to detect a single fundamental tone from a mixture of sounds entering the lower opening with his ear at the upper pointed opening. The resonator was initially blown from glass and later formed from brass sheet.
The task of sound absorbers is to convert sound energy into other forms of energy. They are used in the fields of noise protection and acoustics/room acoustics. Sound absorbers are divided into the following groups according to their mode of operation:
- porous absorbers
- resonance absorbers (Helmholtz resonators)
- combinations of both
