Now lets take the basic RIAA (Flat Xover),
and form two more of the most popular EQs:
(D) The NARTB Standard: (Artist, Capitol, M.G.M., and many other American pressings) = (C) The 500 Hz Flat Xover + a cap:
(E) The Columbia Microgroove: (NARTB + a resistor):
Well, it shouldn't take much imagination to wire up a switch or two to eek out at least 5 RIAA EQ settings.