  We present a survey of how the spectral features of black hole X-ray binary
systems depend on spin, accretion rate, viewing angle, and Fe abundance when
predicted on the basis of first principles physical calculations. The power law
component hardens with increasing spin. The thermal component strengthens with
increasing accretion rate. The Compton bump is enhanced by higher accretion
rate and lower spin. The Fe K$\alpha$ equivalent width grows sub-linearly with
Fe abundance. Strikingly, the K$\alpha$ profile is more sensitive to accretion
rate than to spin because its radial surface brightness profile is relatively
flat, and higher accretion rate extends the production region to smaller radii.
The overall radiative efficiency is at least 30--100% greater than as predicted
by the Novikov-Thorne model.
