Bass reflex speakers use Helmholtz resonators for bass reproduction. Such an acoustic resonator
is a hollow body with an opening. The
air in the opening bounces on the air cushion of the resonator.Inthis context one also speaks of the spring stiffness, which depends on the volume of the body. This spring stiffness is used in loudspeaker technology to tune the bass reflex box in such a way that the low frequencies are preferentially emitted. In practice, a tube is used as a resonance body and the resonance frequency
ischosen in such a way that the low frequencies are amplified.
The Helmholtz resonator is found in many musical instruments
It is the body of the instrument, for example the violin body. It is not the cavity resonators like those of organ pipes or those of a flute.
Helmholtz resonators can be used to boost frequencies, but they can also be used to absorb them. Such resonators are used in room acoustics as absorbers
, for example, as insulating panels with holes, each of which forms a Helmholtz resonator. The Helmholtz resonator is named after its inventor, the German physicist Hermann Ludwig Ferdinand von Helmholtz (1821-1894), who formulated the law for the conversion of energy forms in 1847.