In my experience, I agree with what others have said previously about EJ45 and EJ46 being neutral sounding strings. I'll say "neutral" as they are clear sounding and colorless. They have been this way on several guitars I have owned.
I've tried other strings that had a "golden" sound, or "brown" sound, and various bases that have varying degrees of dark tone. On one of my guitars, the Cantiga basses give a dark, silver color to the sound.
It just seems that when strung with Pro-Arte, any sound that you are getting is the sound of the woods of the guitar, without any added distraction that other, color heavy strings, seem to add.
I know, those of us who see colors in respect to hearing sounds, are probably crazy. Guilty as charged, I guess