Described embodiments relate to a method of manufacturing a sound absorption material. The method comprises: forming a low density fibrous web to act as a porous bulk absorber, the fibrous web containing a proportion of bi-component fibres, each bi-component fibre having a core material and a sheath material around the core material, the sheath material having a lower melting point than the core material; applying a thin facing layer to the low density fibrous web, wherein the facing layer is adhesively compatible with the sheath material; heating the fibrous web to a temperature sufficient to soften the sheath material of at least some of the bi-component fibres; and pressing the facing layer and fibrous web together under low pressure such that at least part of the facing layer contacts the softened sheath material of at least some of the bi-component fibres to form an adhesive bond between the facing layer and the fibrous web.