  We extend Kodama-Ishibashi and Jansen-Rostworowski-Rutkowski master field
framework to study quasinormal modes of black branes and black holes of
Einstein gravity in $D=5$ space-time dimensions with multiple scalars and an
arbitrary bulk potential. As an application, we consider a thermodynamically
unstable state of mass deformed ${\cal N}=4$ supersymmetric Yang-Mills theory
at strong coupling. The corresponding gravitational dual is ${\cal N}=2^*$
black brane with a dynamical instability of its translationary invariant
horizon. We study the dependence of the quasinormal mode spectra as the
boundary gauge theory is compactified on $S^3$ -- the black brane is turned
into the black hole.
