Higher-order topological states in sound have played a pivotal role in advancing our understanding of the intricate physics underlying sound transport, leading to new strategies for manipulating sound. In this study, we report a tunable structure for hinge skin states in a non-Hermitian acoustic metamaterial exhibiting a hybrid skin-topological effect. Our findings show that when on-site gain and loss are exquisitely introduced into acoustic topological insulators, chiral edge modes in their Hermitian counterparts are respectively amplified or attenuated at zigzag boundaries. By intentionally constructing adjacent gain and loss boundaries, hinge skin states emerge at their intersections. Through the strategic combination of non-Hermitian and topological physics, we successfully reveal how higher-order hinge modes originate from lower-order surface states and demonstrate flexible acoustic steering in a tunable non-Hermitian acoustic metamaterial. Our findings unveil that skin-topological effect could have significant applications in the design of innovative acoustic devices with unconventional functions such as multidimensional acoustic control and precise energy harvesting.

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• Edge states
• Non-Hermitian systems
• Topological insulators