  We consider scattering of minimally coupled scalars from a six-dimensional
black string carrying one and five brane charges but no Kaluza-Klein momentum.
The leading correction to the absorption cross section is found by improved
matching of inner and outer solutions to the wave equation. The world sheet
interpretation of this correction follows from the breaking of conformal
invariance by irrelevant Born-Infeld corrections. We note that discrepancies in
normalisation are caused by there being two effective length scales in the
black string geometry but only one in the effective string model and comment on
the implications of our results for the effective string model.
