  The spectral action in noncommutative geometry naturally implements an
ultraviolet cut-off, by counting the eigenvalues of a (generalized) Dirac
operator lower than an energy of unification. Inverting the well known question
"how to hear the shape of a drum ?", we ask what drum can be designed by
hearing the truncated music of the spectral action ? This makes sense because
the same Dirac operator also determines the metric, via Connes distance. The
latter thus offers an original way to implement the high-momentum cut-off of
the spectral action as a short distance cut-off on space. This is a
non-technical presentation of the results of arXiv:1305.2605
