400 i is a lot so show and less substance than the HD 600 . I found the 400 i to be darker toned , thick thick mids that come off as really warm but much less lively and natural than the HD 600 . The bass has more oomph but not that textured . The build is somewhat unique but doesn ' t really feel any more substantial than the HD 600 . The stock 400 i cable is really just horrible . I can ' t stress this one enough I ' ve never hated a cable like I did that one . It ' s short and stiff I have literally no idea what possessed them to make that one . I liked the 400 i box , which was nice , and upon initial inspection , the thing just looks cool and classy kind of . You just don ' t get the same experience as a HD 600 though .