  A formula for the local acoustical admittance in a conical waveguide with
viscous and thermal losses given by Nederveen [(1969) Acoustical Aspects of
Woodwind Instruments (Frits Knuf, Amsterdam)] is rewritten as an impedance
transmission matrix. Based on a self-consistent approximation for the cone, it
differs from other one-dimensional transmission matrices used in musical
acoustics, which implicitly include the loss model of a cylinder. The resonance
frequencies of air columns calculated with this transmission matrix are in
better agreement with more comprehensive models. Even for long cones with a
slight taper, there is no need to discretize along the axis.
