The Etymotic ER-4S is a very neutral universal fit in-ear monitor that has withstood the test of time. It is quite capable for a single balanced armature, but it does lack at both ends of the spectrum. With acoustic music, it performs well, especially when it is simple and mid-centric, but electronic music and complex orchestral pieces can expose the weaknesses at both ends of the spectrum. Soundstage size width is OK, but the depth of presentation and imaging are the weak points of the ER-4S. The ER-4S still deserves to be called a reference IEM, and one would be hard pressed to find a IEM as neutral but more capable for the price.
Read joker’s full review.
