I own the IE 40 Pro and had the chance to audition IE 400 Pro - IE 500 Pro. I'm more active on FB, and there I said, unequivocally, that IE 40 Pro is playing in the $300 league sonically. Sadly to say, the big brothers also play in that league. IE 400 Pro is good, nothing problematic standing out, but also forgettable. IE 500 Pro has, IMO, a dark sound. Some folks in the SE846 camp may enjoy that. But my AKG N5005 shattered IE500 Pro with much better tonality - bass - mid - treble - speed. And I have sold my N5005 because my LZ A6 (with a bit of foams) offers a slightly better sound at significantly lower price.