  This paper focuses on the spectral properties of the mass and stiffness
matrices for acoustic wave problems discretized with Isogeometric analysis
(IGA) collocation methods in space and Newmark methods in time. Extensive
numerical results are reported for the eigenvalues and condition numbers of the
acoustic mass and stiffness matrices in the reference square domain with
Dirichlet, Neumann and absorbing boundary conditions, varying the polynomial
degree $p$, mesh size $h$, regularity $k$, of the IGA discretization and the
time step $\Delta t$ and parameter $\beta$ of the Newmark method. Results on
the sparsity of the matrices and the eigenvalue distribution with respect to
the degrees of freedom d.o.f. and the number of nonzero entries nz are also
reported. The results are comparable with the available spectral estimates for
IGA Galerkin matrices associated to the Poisson problem with Dirichlet boundary
conditions, and in some cases the IGA collocation results are better than the
corresponding IGA Galerkin estimates.
