  In this paper, we investigate the stability of the linear wave equation where
one part of the boundary, which is seen as a lower-dimensional Riemannian
manifold, is governed by a coupled wave equation, while the other part is
subject to a dissipative Robin velocity feedback. We prove that the closed-loop
equations generate a semi-uniformly stable semigroup of linear contractions on
a suitable energy space. Furthermore, under multiplier-related geometrical
conditions, we establish a polynomial decay rate for strong solutions. This is
achieved by estimating the growth of the resolvent operator on the imaginary
axis.
