  In his recent work, Voiculescu generalized his remarkable formula for the
quasicentral modulus of a commuting $n$-tuple of hermitian operators with
respect to the $(n,1)$-Lorentz ideal to the case where its spectrum is
contained in a Cantor-like self-similar set in a certain class. In this note,
we treat general self-similar sets satisfying the open set condition, and
obtain lower and upper bounds of the quasicentral modulus. Our proof shows that
Voiculescu's formula holds for a class of self-similar sets including the
Sierpinski gasket and the Sierpinski carpet.
