Surface liner member intended to be applied onto a base surface in order to reduce, by acoustic absorption, an acoustic wave that is reflected on the base surface through the surface liner member, said surface liner member comprising: - an external wall which is provided with multiple holes, each hole individually forming an open passage through said external wall; - a spacer structure, which is connected to an inner face of the external wall and adapted to set a gap between said external wall and the base surface, so as to form at least one acoustic cavity between the inner face of the external wall and the base surface; and - tubes, which are connected to the external wall and which extend into the acoustic cavity from the inner face of said external wall, towards the base surface, each tube being open at two opposite ends of said tube and being dedicated to one of the holes in the external wall with a hole section that is contained in an inner section of the tube at the external wall, wherein a length of each tube is smaller than the gap between the external wall and the base surface, said tube length being measured along a direction perpendicular to the inner face of said external wall, so that at least 10% of the gap between the external wall and the base surface, against said base surface, is devoid of tubes, and characterized in that several of the holes in the external wall have different cross-sectional shapes, such that a quotient of a hole cross-sectional perimeter divided by a hole cross-sectional area varies between at least some of said holes, so that an overall apparent peak of acoustic absorption of the surface liner element is enlarged for acoustic wave frequencies that are less than 500 Hz. - an external wall which is provided with multiple holes, each hole individually forming an open passage through said external wall; - a spacer structure, which is connected to an inner face of the external wall and adapted to set a gap between said external wall and the base surface, so as to form at least one acoustic cavity between the inner face of the external wall and the base surface; and - tubes, which are connected to the external wall and which extend into the acoustic cavity from the inner face of said external wall, towards the base surface, each tube being open at two opposite ends of said tube and being dedicated to one of the holes in the external wall with a hole section that is contained in an inner section of the tube at the external wall, wherein a length of each tube is smaller than the gap between the external wall and the base surface, said tube length being measured along a direction perpendicular to the inner face of said external wall, so that at least 10% of the gap between the external wall and the base surface, against said base surface, is devoid of tubes, and characterized in that several of the holes in the external wall have different cross-sectional shapes, such that a quotient of a hole cross-sectional perimeter divided by a hole cross-sectional area varies between at least some of said holes, so that an overall apparent peak of acoustic absorption of the surface liner element is enlarged for acoustic wave frequencies that are less than 500 Hz. wherein a length of each tube is smaller than the gap between the external wall and the base surface, said tube length being measured along a direction perpendicular to the inner face of said external wall, so that at least 10% of the gap between the external wall and the base surface, against said base surface, is devoid of tubes, and characterized in that several of the holes in the external wall have different cross-sectional shapes, such that a quotient of a hole cross-sectional perimeter divided by a hole cross-sectional area varies between at least some of said holes, so that an overall apparent peak of acoustic absorption of the surface liner element is enlarged for acoustic wave frequencies that are less than 500 Hz.