Pros: + Balanced and natural tuning
+ Musical and engaging
+ Very effective sound tuning system with four profiles
+ A real all rounder
+ Clear and resolving
+ Great technicalities for the price
+ Open sounding with accurate imaging
+ Very comfortable
+ Good passive noise attenuation
+ Easy to drive
+ Well made
+ Good quality cable and carrying case
Cons: – Soundstage is not that grand and holographic
– Sometimes bass can sound a little hollow and sluggish
– Not that impactful and dynamic
– A modular cable is really missing
The review sample was kindly provided free of charge in exchange for my honest and subjective evaluation.
I haven’t received monetary or any other kind of compensation and I don’t use affiliate links.
The price of the MD4 is $189 and can be ordered from Hidizs online shop.
Hidizs was founded early in 2009, when pocket HiFi had just become a thing.
At that time, they were pricey and badly made.
Digital music sucked in those days, but people didn’t really care.
Tamson, the founder and the CEO of Hidizs, did care.
He was an audiophile and fronted an underground rock band in college. After graduating, Tamson dedicated his life to making HiFi music players for lossless music.
As an audiophile, it was a no-brainer; music should be heard as it was intended to be.
In order to produce better quality portable HiFi audio devices at an affordable price, Tamson brought together a group of audiophiles with extensive backgrounds in HiFi audio R&D.
With a core staff of over 40 audio-obsessed professionals and decades of combined experience, Hidizs has been able to consistently produce the highest quality portable digital audio players (DAPs), earphones, USB DACs, etc.
You can read more about Hidizs history here.
The MD4 is the newest addition in the long growing Hidizs series of earphones that consists of the Mermaid MM2, MS1, MS2, MS4 and Seeds.
The MD4 features 4 custom-designed BA Drivers developed and tuned for years by Hidizs professional audio team, 2 for the lows, 1 for the mids and 1 for the treble.
A redesigned internal audio transmission structure with high-precision 3D printing straight acoustic sound tube is made to ensure continuous and clean audio output of the custom-designed 4-BA drivers, reduce overlap and interference of sounds between multiple drivers.
Effectively increasing sound density, reducing distortion and harmonic resonance to ensure accurate audio crossover, excellent performance and layering.
A 3-way electronic crossover with professional audio capacitors is used to accurately calculate the connection of different frequency bands, reasonably allocating high, ultra-high, medium, and low frequencies, increasing accuracy and clarity for all, mutually balanced and harmonized. Hidizs’ decades of experience in acoustic tuning ensure MD4’s outstanding performance in different frequency bands.
Four different tuning styles
The highlight feature of the MD4 is that the user can choose between four different tuning styles by means of a 2-level tuning switch that controls the electronic crossover.
Two tiny and very discreet micro-switches that can be set as ON or OFF are located at the bottom part of each earshell.
The available combinations are four and they offer the following tuning styles as explained by Hidizs.
Balanced: Classic Hidizs tuning, suitable for most people’s listening styles.
Warm: excellent performance at all frequencies, stronger musical sense. Suited for folk & pop music.
Treble: remarkable highs/ultra-high. Suited for rock and electronic music
Bass: boosted bass with excellent speed and a tight response. Suited for symphony and classical music.
Design and build quality
Each earshell is constructed in a combination of three different parts.
A celluloid faceplate with handmade plating: laser-cut and hand-polished, with the beautiful amber finish that is lined with EU IIA certified medical-grade skin-friendly resin.
An aluminum-alloy CNC rose-gold middle frame and aluminum alloy output nozzle.
A combination that is not only aesthetically pleasing, elegant and beautiful looking but it also guarantees output purity and stability for reduced harmonic resonance and distortion.
The MD4 has an excellent build quality and is available in black, indigo and white.
Wearing comfort and isolation
The ear shells, which are not too bulky, are anatomically shaped following the natural ear curve while the headphone connector adopts an ergonomic elbow design for added wearing comfort.
Weight is as low as 7g per piece and the actual wearing experience is very comfortable and stress-free even after extended time of use.
The ear shells fit tight and stay stable thus offering good passive noise attenuation.
The MD4 has a 0.78mm 2-pin detachable cable with gold-plated sockets for more stable and smooth audio transmission.
The cable is made from a combination of 60 high-purity silver wires + 60 high-purity oxygen-free copper wires tightly twisted in four strands and is terminated with a 3.5mm plug.
The plugs are of high quality and the cable is well built, it is soft to the touch, it has good handling, it doesn’t get tangled and has very low microphonic noise.
It is an excellent made cable but it should be noted that these days most of the competition comes with a modular plug cable for balanced connection.
The MD4 comes together with one of the most beautiful and well made carrying cases in the market.
A brown colored, handmade case from premium, water-proof, sustainable polyurethane leather, designed with magnetic clasp and iron-reinforced leather to prevent shape loss and provide maximum protection.
Inside the box you are also going to find three different types of eartips (balanced, vocal, bass) in three sizes each and a handy tool for cleaning and adjusting the tuning switches.
The MD4 has an 8Ω rated impedance with a sensitivity as high as 102dB so it is very easy to drive but it does need a quality source that doesn’t hiss like the Hidizs own S3 Pro or the FiiO KA1.
Furthermore the MD4 has quite good scaling potential so you are welcomed to experiment with higher quality sources like I did with the Violectric Chronos and Hidizs AP80 PRO-X.
The tuning switches are much more effective at altering the frequency response of the earphone than the interchangeable sound tube system.
With the MD4 you get four easily distinguishable sound profiles making for a very versatile earphone that can suit different moods and music styles.
Each setting will not only affect the frequency part that its name would suggest, instead it offers a wider band adjustment.
The “treble” and “balanced” settings share a “V” shaped sound profile that is more pronounced in the former while “warm” and “bass” don’t only boost the low end but they also bring some forwardness into the mids, adding extra presence.
All sound profiles share a well-balanced bass response that can range between the most emphasized in the “bass” setting or mildly subdued in the “treble”.
Overall sub-bass extension is more than enough for all acoustic instruments, including the pipe organ, while it is certainly adequate in quantity for synthesized tunes as long as you don’t seek a bass shuttering experience.
Some differences apply for the various sound profiles but generally speaking the bass is distinguished by its natural timbre while it doesn’t bleed into the mid-range nor coat the upper frequencies.
Technicalities range from good to very good, the bass setting offers the best of them in exchange for some extra mid-bass emphasis that results in a slightly artificially colored tonality.
Texture is not that visceral but it is well defined and controlled, clear and detailed with minimum internal masking although it could use some extra refinement.
The MD4 has fast attack and speed but it should be noted that it can sound a little sluggish and hollow in busy pieces with multiple stringed bass instruments.
Dynamic behavior is satisfying and realistic but slightly behind and not as impactful as some other earphones with large dynamic drivers.
The mids can range between slightly recessed to mildly forward according to the switch settings.
“Bass” and “warm” belong to the latter group while “balanced” and “treble” to the former.
All settings share the same natural and slightly warm timbre with realistic tonality, pluralistic overtones and excellent clarity.
Voices, both female and male, might get some different gravity according to the tuning setting but they always sound quite special, lush and engaging with a clean and well expressed articulation while the same qualities also apply to the instrumental groups.
The treble can also range from mildly forward and a touch bright (but not harsh or piercing) to slightly recessed and smooth but never lacking in overall extension at any given setting.
This is the actual benefit of the electronic crossover tuning system rather than relying on the interchangeable sound tubes.
It is always better to be able to adjust a wider frequency band rather than a narrow portion of it because this way you get a smoother tuning without excessive and unpleasant sounding peaks.
The top end is open, airy, sparkling and shimmering without overdoing it while the MD4 is resolving and quite detailed without sounding analytical.
Of course there is a great chance that some users might find the tuning as too safe even under the “treble” setting and others might wish for a more detailed and analytical sound.
The soundstage is open and spacious with precise imaging and plenty of air around the instruments but it is not that grand in scale nor too holographic or deep.
Still, the MD4 is an earphone that can do very well with the most demanding symphonic or vocal works while the listener can enjoy good clues of the recording ambience.
All in all, the MD4 is a mature and natural sounding earphone with a very homogeneous sound, thanks for the excellent driver cohesion, with a refinement that punches well above the price point but it’s greatest achievement is that it feels at home with all kinds of music.
I really enjoyed the whole of my playlist but the specialty of the mid-range combined with all the other qualities made me want to listen to large scale choral works and operas.
In the end
The MD4 is a real chameleon earphone as it can easily adapt to suit various moods and music styles.
With four different tuning profiles there is no way not to find your favorite one while no matter the setting it always sounds musical, engaging and tonally correct.
It is also very comfortable, well made, it comes along with one of the best carrying cases and the only thing really missing is a balanced cable that would make it even more versatile.
A mature and well designed earphone from Hidizs, a true “all rounder” that will easily satisfy both casual and critical listeners alike.
Copyright – Petros Laskis 2022.