absolute velocity seemed higher in relation to normal-space. The physicists assured her she wasn't really moving at more than light-speed, but the practical result was FTL travel.
Still, there were limitations. The multi-dee was unusable inside the "Frankel Limit," a flexible point in stellar gravity wells which varied widely depending on spectral class and vessel mass, and though one theoretically could simply translate directly from normal-space into whatever other dimension one chose to use and vice versa, it was far wiser to translate gradually from one to another.
Dimensional energy flux could be vicious, and many things could happen to people who took liberties with the multi-dee. Few were pleasant. The alpha band—the "lowest" of all—was only about twenty dimensions across. t