On the mark. However the only differences are that the 400's have a bit more bass quantity, while the 500's have a bit more extension, smoother mids, and treble emphasis (relative, due to the lowered bass quantity). One thing for certain though, The HE400's still retain the hifiman house sound (not-rolled-off bass, realistic mids and treble, great imaging and layering) not to mention physical look and weight and comfort level, would give AppleDappleman a much better idea of whether HE500's would be a good idea for him or not.