The SR8000 is a good sounding receiver but doesn't have a place to connect an EQ. No processor or tape monitor loop. No amp inputs. So the only way to use an EQ on all sources is to connect it in between the receiver preamp output and the input of a power amp. You could connect one in between one analog source and the receiver. If you use a computer as a source you can use a software program to EQ the speakers.
https://sourceforge.net/projects/equalizerapo/
EQ can make a bit of an improvement with vintage speakers like those but it won't make them sound like a well designed modern speaker. The tech is just way to old with problems that an EQ can't fix. You can only apply a very limited amount of boost before it will damage the speaker.