The MS4 is a W-shaped earphone with lightly warm lows, prominent vocals and a modestly bright high-end soothed by a smoother lower-treble. This grants it a grand, inviting sound that will surely provide wide appeal. Its very prominent vocal range will no doubt please Asian audiences while bold, expansive lows add scale and depth to its image. The MS4 isn’t a neutral earphone though it has nice balance between the three core frequency zones. All comments are using my preferred balanced ear tips.
The MS4’s low-end draws immediate attention with its strong extension and large, bold notes. That said, it doesn’t dominate the sound. Sub-bass has notable emphasis with a smaller mid-bass bump increasing note body and warmth. Bass notes are big and sub-bass rumble and slam are obviously enhanced as a result. That said, bass comes across as somewhat boomy and at times, ill-defined due to its sub-bass focus. As can be expected from most earphones with emphasized sub/mid-bass, upper-bass is attenuated as is the lower-midrange to maintain a tonally transparent midrange.
Bass decay is on the slower side with notes lingering longer than on most earphones. This produces a smoother bass texture so bass definition and detail retrieval are above average but not exceptional. Bass control is quite good, however, so notes don’t become smeared or muddy and performance is clearly better than earphones the next price tier down. That said, the MS4 appeals to those wanting for scale and depth over detail and definition.
Vocals stand out most in the MS4’s sound, a result of large emphasis through the centre and upper-midrange. As emphasis sustains until just before the lower-treble region, the midrange is granted large clarity. Unlike, the otherwise similarly tuned Fiio FH5, no 4K dip is present so it sounds slightly cooler and thinner but also cleaner and more extended. Vocals are clearly biased over instruments yet the added bass weight does rectify this to some degree.
As aforementioned, upper-bass and lower-mids are slightly attenuated. Though as it is to a reasonable degree and the earphone has a slightly warmer low-end, midrange timbre is quite good. Vocals are clearer than neutral and just slightly cool, but they are clean and defined. Moreover, as lower-treble is attenuated, the earphones have zero issues with sibilance and over-articulation, sounding impressively refined. Though not perfectly natural, nor balanced, the MS4 nonetheless, offers a subjectively well-tuned presentation that is clean and engaging.
It’s interesting to see Hidizs adopt a lower-treble recessed, middle-treble forward style of tuning and execute it with success. This is definitely an atypical tuning style, yet one that works wonders for this earphone’s midrange while keeping fatigue in check. As lower-treble is less present within the mix, instruments don’t have heaps of bite nor are details presented with much attack or sharpness. Rather, the MS4 has a smooth foreground with a greater focus on texture over crispness. Yet, as the middle-treble is enhanced, it can hardly be said that the MS4 is lacking detail presence. In fact, this earphone is very well-detailed, with heaps of air, openness and shimmer.
Instruments have a slightly exaggerated decay which provides the impression of greater detail. Even so, foreground detail retrieval is strong and smaller background details are brought to the fore without wearing on the ear with their sharpness. The background is not clean or dark, but rather open and expansive. This is aided by strong extension into the highest octaves that provides great resolving power and micro-detail retrieval. Upper-treble is rather linear so the earphones don’t sound overly tizzy. Though not traditional and perhaps, detail recessed to some on first listen coming from more aggressive earphones, the MS4 is very well-detailed, nicely balanced and technically impressive.
Expansion is good, stretching just beyond the head. The MS4 has an impressively rounded stage with great lateral expansion and the ability to project quite far in terms of depth which seems contradictory to its vocal forward tuning. Imaging is mediocre as bass is on the slower side and lower-treble is less prominent, it can be difficult to locate instruments and directional cues precisely. That said, centre image is strong and separation is quite good besides bass where thicker notes occupy space and diminish separation.
The MS4 has a high sensitivity of 112dB and a lower 12-ohm impedance. Due to their efficiency, they reach very high volumes from almost any portable source, however, they also pick up hiss quite easily. Being a multi-driver, a low output impedance source is preferable. In use, the MS4 is easy to drive. When driven from the iBasso DX200 w/AMP5 as opposed to the Pixel 3 with included 3.5mm adapter, the MS4 sounded noticeably more controlled with a more spacious soundstage. From subjective testing, the Pixel 3’s audio adapter does not have the highest output impedance, though the MS4 does not appear overly affected in terms of signature nonetheless.