Riff and bassline problem

[mphasis]

I was just wondering if anyone can help me out.I'm having a bit of trouble making my basslines and riffs sit together.The lower notes in the riff are interfering with my rolling bassline making a muddy mess.When i put a riff and bassline together with other plugins like nexus there's no problem but when i do it with my virus TI the sounds sound to big.It sounds like the cycles of the oscillators going back and forth to me making parts stick out more,but what do i know i haven't got a clue lol.Do you have to EQ the riff so the lower notes are quieter?

If anyone can help that would be great,Thanks.

By the way i'm making hard trance.