ACOUSTIC MATERIAL
An acoustic material is intended to be mounted behind a loudspeaker 8 to decrease the resonant frequency and/or to reduce the back volume. The acoustic material includes a woven or non-woven fabric which supports highly porous particles or fibers such as particles of carbon black. The woven or non-woven is thin and light to avoid damping sound, whilst still being capable of retaining the porous material. The use of a flexible acoustic material allows the material to be more easily included with loudspeakers in portable mobile devices.
1 . An acoustic material comprising:
a flexible woven or non-woven fabric;
a porous material contained by the fabric, the porous material being made up of particles or fibres;
characterised in that the porous material is incorporated in the fabric and the fabric has a specific weight of no more than 25 g/m 2 and a thickness of no more than 70 μm.
2 . An acoustic material according to claim 1 wherein the hole size of the fabric is at least 1 nm but not more than 100 μm.
3 . An acoustic material according to claim 1 wherein the fabric is made of hydrophobic fibres.
4 . An acoustic material according to claim 1 wherein the porous material is activated carbon.
5 . An acoustic material according to claim 1 wherein the fibres of the fabric are of plastics material.
6 . A loudspeaker arrangement, comprising:
a loudspeaker cavity; and
an acoustic material according to claim 1 mounted in the loudspeaker cavity.
7 . A mobile device, comprising:
a housing;
a loudspeaker diaphragm mounted in the housing; and
an acoustic material according to claim 1 mounted behind the loudspeaker diaphragm in the housing.