The sub-bass of the IE 400 Pro has great extension. The sub-bass reproduction is agile and impact is brought out well. The bass decay is on the quicker side of things and there is high engagement level. The bass texture is rendered smoothly. The mid-bass has good body and the slam is delivered aptly. Each bass note is articulated well with precision and there is clean hit.
The midrange is presented with high transparency level and there is good details retrieval. Vocals on the IE 400 Pro are expressed well albeit with a leaner presentation. The lower midrange has fair quantity and male vocals are presented clearly without any dryness. The upper midrange has more emphasis and female vocals are more forward. The IE 400 Pro has a focused and detailed midrange.
The treble commands great extension and there is precise articulation. The treble has fair body. The crisp is well-defined and there is slight sparkle to liven up the top end. The amount of air rendered is good. The treble expression is detailed. The IE 400 Pro displays its treble cleanly.
The IE 400 Pro has a natural soundstage expansion and the width has good magnitude. There is effective amount of depth. Positioning of vocals and instruments is accurate.