Surround sound receivers don't usually have a tape monitor loop or preamp out - amp inputs so there is no place to connect the EQ. Stereo receivers often have these connections
If your receiver has front L/R preamp outs you could buy a power amp and wire the EQ between the receiver and amp (connecting the speakers to the amp).
If you don't have preouts you would also need a speaker to line level adapter which would wire to the front speaker outs and provide a line level signal for a separate amp.