Robust high-efficiency and broadband acoustic absorber based on meta-molecule cluster sets

•The absorber consists of meta-molecules could realize near-perfect absorption mainly originates from the friction loss of acoustic wave in narrow channels and orifice and also could offer absorption tenability within a wide frequency range by adjusting parameters..•The proposed absorber can achieve broadband and multiband absorption by combining meta-molecules of different parameters based on the physical principle that weak interaction between metamaterial elements.•We further propose an optimization method that achieves broadband absorption for effectively filling ‘acoustic absorption valley’ by utilizing the coupling between porous materials and meta-molecule cluster.