You would not be able to use the 901v4 EQ with the 301s. Could actually damage them if you tried.
If you are using an AVR there will not be anywhere to connect the EQ anyway. An EQ would require a tape monitor-processor loop or preamp out-amp in which are very rare on AVRs. If you had a preamp-processor and power amp then you could connect the EQ in between them.
If you can't find the correct EQ then get a generic EQ and adjust the sound to your liking.