  Applying the semiclassical model, we identify two connected effects in
intraband high-harmonic generation (HHG): (1) propagation time from the point
of emission at the source to the point of detection, (2) beyond-electric-dipole
corrections to the light-matter interaction. These effects inherit information
regarding the dispersion and cause specific features in the spectra including
even-ordered harmonics in systems with space- and time-inversion symmetry. They
can for certain experimental geometries be measured free of the dipole
background.
