are generalized to the multivariable case with
the goal of maximizing generality while retaining robust numerical
properties and simplicity of realization. Multivariable complex power
is defined, and conditions for ``medium passivity'' are presented.
Multivariable complex wave impedances
, such as those deriving from
multivariable lossy waveguides
, are used to construct scattering
which yield frequency dependent scattering
which can be implemented in practice using digital filters
general form for the scattering matrix
at a junction of multivariable
waveguides is derived. An efficient class of loss-modeling filters
is derived, including a rule for checking validity of the small-loss
assumption. An example application in musical acoustics is given.