Sound field
The amplitudes of the sound pressures are displayed . The calculation was carried out using the Rayleigh integral.
A sound field is the area in an elastic medium in which sound waves propagate. The five quantities listed below belong to the sound field quantities, in contrast to the sound energy quantities .
In fluids
In gases and liquids ( fluids ) the sound propagates as a longitudinal wave . The occurrence of sound waves in fluids is characterized by the following quantities, each of which describes a spatial and temporal fluctuation around a spatially and temporally constant mean value :
- the alternating sound pressure : fluctuation of the pressure p ( force per area) within the medium, in Pa = N / m 2 ,
- the alternating density : fluctuation in density ρ (rho) ( mass per volume) of the medium, in kg / m 3 , and
- the speed of sound : fluctuation in the speed v ( distance per time) of the medium particles, in m / s.
In solids
In solids , sound can propagate in the form of longitudinal and transverse waves . They are described over
and can transform into one another through mode conversion at the interfaces of the solid .
No sound field in a vacuum
In vacuum , without a transmission medium is no sound propagation possible; so there is no sound field there either.
Classification
In a closed room, the sound field is divided into a direct field ( free field ) and a diffuse field (also a statistical sound field ) or, depending on the distance from the sound source, into near field and far field, depending on the acoustic properties of the room . Furthermore, a distinction is made between the flat sound field , in which the propagation of the sound waves takes place perpendicular to the propagation of standing wave fronts .
Individual evidence
- ↑ Jecklin, Jürg: Theory of Sound Technology, University of Music and Performing Arts Vienna, Institute for Electroacoustics. Section: Sound field and sound field sizes. Vienna 8/2002