The shape of MS5 is interesting, they are incredibly comfortable in practice, and the outer shell looks like they would be semi-open, but they actually isolate really well from the outside noise, with in between 22 and 28 dB of passive noise isolation, depending on the frequency. The inner shell is made of aluminum, and it is anodized with aluminum oxide for the best resonance and hardness, while keeping it as thin and light as possible.
The overall signature can be described as natural, U-Shaped inspired, with a strong low end bass, strong bass, natural sounding midrange, and a sparkly, energetic treble. The soundstage is quite surprising, it has a natural size, but the instrument separation is quite excellent, and there’s a really good sense of resolution in all frequency ranges. The midrange is really rich, detailed and clean, with no distortion regardless of the volume, and MS5 handles dynamics really well.
The price / performance ratio of MS5 is insanely good, and it quickly became one of my favorite sounding IEMs, it is really impactful and has a good sense of dynamics, plus a natural soundstage, and a really nice high-end package with a practical transport case, and a selection of pneumatic filters if you want to tune the sound. Even in their default state, the performance is surprising, and they have detail and resolution to be competitive in the midrange market, showing that HIDIZS can totally keep up with the currently active IEM market, and making a good entry at that too.