I have a pair of M22s as main monitors, a VP100 center and a HSU VTF-2 sub hooked up to an Onkyo 595. I inherited a 12 year old pair of Advent Baby II speakers that I would like to use as rear surrounds but cannot find info about the speaker's impedance. The Onkyo 595 cannot drive anything lower than 4 ohms. Does anyone know anything about these Advents?