Hidizs MD4 4 Balanced Armature Drivers


100+ Head-Fier
Hidizs MD4: Warm, well built all-BA IEMs
Pros: Soundstage is pleasingly wide
Good timbre
Effective switches (3 of the 4 settings)
Nice set of accessories
Build quality
Passive sound isolation
Cons: Cable is just OK
Pressure during ear insertion might bother some people
Firm connectors
A little BA tonality on Treble tuning (both switches down)
The Hidizs MD4 is a 4 balanced armature in-ear monitor, released in 2022.

Hidizs recently reached out to me to ask me to review this set, asking for no editorial control at all, only that I post these non-affiliate links to purchase the MD4:

Hidizs store

Amazon UK

I was definitely intrigued, especially as I had my eye on these since buying the MP145. Credit to Hidizs for giving me the freedom to write freely. When you have faith in your products, you can trust them to speak for themselves.

Prior to my review sample of the MD4, the only Hidizs products I owned were the planar MP145 and single DD MS1. The MP145 really put Hidizs on my radar: With great timbre, technicalities and an amazing sense of space, it remains my favourite planar.

Going into this review, I had 3 main questions:

  • Did the MD4 have anything in common with the similarly priced MP145?
  • Would the 4 balanced armatures give a sufficiently rich tone, especially in the low end?
  • Could a set from 2022 keep up with the newer releases?


The Opening Experience

The unboxing of the MD4 certainly gives the impression of a premium product. A smart and tasteful box opens to reveal the IEMs themselves. Subsequent layers of the package yield several sets of tips and a cleaning tool, then a storage box containing the cable.


Before getting on to the IEMs themselves, I have to say that I found the accessories to be above average. Three full sets of tips (helpfully labelled as Vocal, Balanced and Bass), and a magnetic case that feels very premium. The included cable is sounds better than the average bundled cable, though is a bit thin. I did change to a premium third-party cable, which added a little smoothness and extension. The cleaning tool is nice enough if you use them, but also can be used to flick the micro-switches – more on those later.


The MD4s have a metal body, with a pearl-effect inset on the faceplate. My set is black, but there are white and blue versions available. They feel solid and well made, and in my opinion look quite classy. The 2-pin connector on my set was a little tighter than most, but not to the point that a cable felt stuck. There is gentle contouring all around the shell, resulting in a very comfortable fit.

As far as I can tell, the MD4 is unvented. This results in pressure on the eardrums when putting in the IEMs, when using some types of tips (such as KB07). If you are sensitive to such things, that could be a dealbreaker, but it shouldn’t be a problem for most people.

The final feature I want to mention is the micro-switches. Each earpiece has 2 switches, giving 4 settings from bright to bassy. They feel solid and as well made as the rest of the IEM. I’ll talk about their effect later in this review.


The Sound

My first impression was space. I had not expected the soundstage and separation to be standout features, but from the first moments I could hear the relation to the MP145.

The timbre was much better than I expected for 2 year old BAs. These really do sound musical. The tonality is quite rich for an all BA set, and almost never sibilant.

Another big surprise was the bass. Apparently 2 of the 4 BAs are dedicated to bass, and it really shows. These slam and rumble, with quick and textured bass.

The switches give some good control over the tuning. As far as I can tell, switch 1 cuts bass and switch 2 cuts mids. The effects are significant, giving 4 distinct tunings:

  • Treble tuning” With both switches off, the sound is bright but to me it sounds less natural than the other settings. It is also the only tuning that can sometimes be sibilant. This tuning is adequate, but the MD4 seems to be held back from its full potential.
  • Balanced tuning” (Switch 1 on + switch 2 off) gives a mild V tuning. With the bass to balance the treble, the MD4 starts to sound really good.
  • Powerful tuning” (Switch 2 on + switch 1 off) emphasises mids and vocals. It does so effectively, and loses the subdued quality of the Treble tuning. Another fun sound from the MD4.
  • Bass tuning” With both switches up, the sound becomes full and rich. It might be a little too full-bodied for trebleheads, but this is my favourite tuning.

Overall the MD4s sound very good, with the layering and space of a multi-BA setup but without the thinness and low bass that is often associated with all-BA sets.


The beautiful Audiosense DT600 is the closest driver setup I have to the MD4, with 6 BAs. The shell is lighter than the MD4, and even more contoured. The build is similarly excellent, though resin rather than metal.

I find the technicalities of the DT600 to be a half-step better than the MD4, particularly soundstage and layering. On the other hand the timbre of the MD4 is ahead of the DT600, and the bass is significantly more prominent.

The tuning of the DT600 is closest to the Treble tuning of the MD4, and it does that treble-forward style much better. For richer, bassier music, the MD4 is the superior choice.

Overall these two IEMs are both very competent, but will appeal to different listeners: If you want a gorgeous all-BA treble boosted IEM with great technicalities, the DT600 is a solid choice. Should you want an all-BA IEM that sacrifices some of the technicalities for timbre, versatility and bass, the MD4 is for you.

Another natural choice for comparison is the Hidizs MP145. In contrast to the 4 BAs and tuning switches of the MD4, the MP145 has tuning nozzles and a single planar driver. The reasons for this comparison are that both are tuneable IEMs from Hidizs with a warm, spacious sound.

Physically, the MP145 is significantly larger and heavier. It also requires much more power to drive well, like most planars. The MD4 is more forgiving of weaker sources, but does scale up nicely with a better source.

To my ears, the MP145 is simply better, so long as you have a powerful source. Rich, detailed, and wonderfully spacious. The only thing the MD4 possibly does better is layering.

Despite the win for the MP145 in sound, the MD4 does have some advantages: an easier tuning system, lower price, and it is much more comfortable for those with smaller ears or who don’t like heavier IEMs.


The Hidizs MD4 surprised me, and I have really enjoyed using it as my daily carry for the last week.

While not revolutionary, this 4 BA IEM stands strong against the competition. You could believe that there was a dynamic driver producing the warm tones and satisfying bass, and it is free of sibilance and BA tonality (except on the lackluster down-down “Treble” tuning). It feels like the little brother of the fantastic MP145.

While I would not recommend the MD4 to everyone, if you are looking for an IEM that has a choice of several warm tunings, has good timbre and technicalities, is well built and easily driven, and is both cheaper and lighter than the MP145, then this is a strong option.


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New Head-Fier
Hidizs MD4 Review!
Pros: Clean, versatile sound signature.

Never sounded thin despite exhibiting an all-BA driver configuration.

Excellent tuning switch implementation.

Deep, thick bass (bass and warm config)

Fast transient decay.

Excellent resolution and technical performance (warm and treble config)

Airy, expansive upper frequencies (treble, warm config)

Excellent fit, comfort, and isolation.

Excellent build quality and visual details.

Excellent packaging and included accessories. Lovely!
Cons: Midbass bloat and muffled lower mids are present on “balanced configuration”.

Peaks and slight sibilance are present on “treble” config.

Instances of overlapping in separation and layering are experienced on “balanced” configuration.


Hidizs MD4 Review!

Good day! After 5 days of casual and critical listening, here’s my written review for the Hidizs MD4. The mermaid sings, sort of!

video review here! :

Additional Note/s here:
  • I will be using the MD4 with the stock “balanced” configuration and compare the other modes from there.
  • I don’t read and read FR graphs. I only use my ears, as how earphones should be used.
  • Hidizs sent this unit to me in an exchange for an honest, unbiased review. Rest assured that this review will do its best to devoid from any bias/es as much as possible.
  • The following remarks and observations shall be made and owned only by me.
  • No monetary compensation is/was involved before, during, and after the period of creation of this review.
  • Your mileage may (and always, will) vary.
Burn-in time: 4-8 hours per day, 5 days.

Source/s used:
  • -Hiby R3 Pro Saber
  • -Fosi Audio DS1
  • -Non-HiFi smartphone (Infinix Note 12 G96), PC.
  • -Local Files via Foobar, YouTube Music, Deezer, and Qobuz with UAPP.
IEM/Earbud/Setup configuration: stock small balanced eartips, stock cable, any form of EQ or MSEB off, 40-60% volume, low gain and high gain.

Sound signature:
  • With the “balanced” configuration set, the Hidizs MD4 exhibits a balanced, mild-v shaped sound signature. From there, the sound varies depending on the switch you configure it with.
  • The lows are slightly elevated and are a bit midbass focused. Despite being an all-BA set, the bass exhibits a slightly softer than usual character to it, but still shows a good amount of articulation and speed. No matter what genre you listen to with this IEM, the Hidizs MD4 is able to cater most tracks easily, particularly in the bass department. There is a midbass bleed present in this configuration, which leads us to the mids.
  • … is quite caved in , recessed, and sounds “off” which makes the mids not as extended and forward the way I prefer in this configuration. This is because of the midbass bleed/bloat smearing onto the mids. In return, lower mids are thick, muffled, and somewhat “boxy”. Male vocals seem to be sounding thicker than usual in this configuration. Upper vocals are slightly elevated in this configuration, exhibiting a good amount of clarity and sparkle. There are some instances of occasional peaks here and there, but nothing too off-putting for me to call it sibilant, strident, or hot.
  • The highs are fairly extended, elevated, with a good amount of air. It isn’t as extended compared to the other configurations. Instances of sibilance in this region are non-existent in this area, but I am aware that there are other inputs experiencing some sibilance in this area, so do take note of those inputs as well if your ears are sensitive to upper frequencies. Detail retrieval in this configuration is average and is improved on other configurations.
Soundstage, Imaging, and separation:

  • The MD4’s technical performance is average in this configuration and gets better on the other configurations. Its soundstage aimed for a more “pseudo-immersive” one rather than your usual wide soundstage due to its height and width nearly having the same depth. Separation and layering are mostly good for the most part, with some instances of overlapping on some heavy passages in this configuration. Imaging is precise and is able to render instrument and vocal positions clearly.
Other Driver Configurations! (U = UP, D = Down)

  • “Warm” Configuration (DU)
    • This by far is the best configuration among the 4 in my opinion. Everything is much more extended, open, clean, and airy. The boxiness of the lower mids are also non-existent in this configuration. Resolution is also noticeably better and microdetails are much more heard in this configuration.

  • “Treble Configuration” (DD)
    • Flattens the bass and extends the treble even further by making things more airier than usual. Bass is more tight, faster, and controlled in quantity. The bloat is also non-existent in this configuration, but some upper mid peaks are more apparent in this configuration. Technical performance here is identical to the warm configuration. Personally this is my favorite configuration, but most people will prefer the “warm” configuration.

  • “Bass Configuration” (UU)
    • Extends and elevates the bass even further, making things more rumbly. The bloat is slightly present in this config, but is definitely shaved or trimmed down compared to the balanced configuration. The rest are more or less the same.

  • Clean, versatile sound signature.
  • Never sounded thin despite exhibiting an all-BA driver configuration.
  • Excellent tuning switch implementation.
  • Deep, thick bass (bass and warm config)
  • Fast transient decay.
  • Excellent resolution and technical performance (warm and treble config)
  • Airy, expansive upper frequencies (treble, warm config)
  • Excellent fit, comfort, and isolation.
  • Excellent build quality and visual details.
  • Excellent packaging and included accessories. Lovely!
  • Midbass bloat and muffled lower mids are present on “balanced configuration”.
  • Peaks and slight sibilance are present on “treble” config.
  • Instances of overlapping in separation and layering are experienced on “balanced” configuration.


The Hidizs MD4 is a very good option if you are looking for a very good sounding IEM with tuning switches under 200 USD. Its versatile, all rounder sound makes it really good for most genres you pair with it. By far, the “warm” setting will suit most listening experiences as it balances both tonality and technical performance evenly, while removing the bloat on the lower mids. Not to mention its very good technical performance for its price on most of its configurations. Hidizs did really well on this set, and I am open to hear more improvements of their works in the future. I’m impressed!
Pairing recommendation/s:
  • Source: This IEM is very easy to be driven, and prefers neutral source.
  • Eartips: Eartips included are soft and good in quality, but you may always use your preferred eartips.
  • Cable: Cable is as good and basic as it gets. You may use your preferred cable as always.
Thank you for reading!

Additional Photos here:





Headphoneus Supremus
Hidizs MD4 - Resolving and Immersive
Pros: - Very good resolution
- Very good soundstage imaging
- Multiple tuning options to match your unique ears and library
- Good accessories, particularly the classy carrying case
Cons: - The default tuning does not leave a good impression (to me)
- The Midrange is still slightly unnatural due to the 1.66kHz dip
- Barely adequate bass performance
- The stock cable can be very annoying

Beyond tonality, what makes a pair of IEM or headphones "good"?

For some of us, it's all about that bass. For others, it's all about "timbre." Personally, I look for the elusive "resolution" and "soundstage." Whilst good tonality is getting cheaper with every new IEM, the same cannot be said about resolution and soundstage. Can Hidizs MD4 change that? Let's find out.

Summary for casual listeners: MD4 is a customisable IEM that sounds relatively pleasant and natural. It is good at separating elements of a recording and placing them around an imaginary sound "stage" around your head. MD4 is well suited for recordings with a sense of space and a lot going on (e.g., orchestral music, soundtracks, and some forms of electronic music). It is not suitable for genres that require a lot of bass.



  • This review is based on a review sample sent by Hidizs (Thank you!). I treat review units as long-term loaned units, meaning I can use them, but they still belong to the manufacturers.
  • I rate IEMs by A/B testing them against a few benchmark IEMs, regardless of price point. If a $1000 IEM scores the same as a $100 IEM, then either the more expensive one underperforms or the budget one is a gem.
  • I believe that great IEMs are the ones that can achieve multiple difficult things simultaneously: (1) high resolution (meaning lines of music are crisp, clear, easy to follow and full of texture), (2) 3D soundstage with a strong sense of depth, (3) bold and natural bass with a physical rumble, (4) natural timbre, (5) relaxing and comfortable tonality. IEMs achieving those criteria are rated highly in my ranking list
  • I use frequency response measurements to double-check my subjective impressions.
  • Ranking list and measurement database can be found on my IEM review blog.

Non-sound Aspects

In the box:






The size of MD4 is above average. However, the earpieces are not as large as I imagined when reading others' reviews. The body of the ear pieces is noticeably thicker than Aria, roughly the same size as S12, and a bit smaller than Blessing 2.

The nozzles of MD4 are average in both diameter and length. They are not chunky like Blessing 2's or short and stubby like S12's. However, they are too large for deep fitting, so the earpieces do not fit snuggly against my conchas like a few other IEMs, such as Monarch Mk2 and Meze Advar.

MD4 earpieces are fully sealed, so you can have a vacuum-like feeling in your ears when putting the IEMs on. On the plus side, the noise isolation is above average, though far behind deep-fitting IEMs from Etymotic and Westone.

I find MD4 average in terms of comfort and usability. I primarily use these IEMs for commutes and daily walks as they are stable, effective in blocking noise, and easy to put on and remove.

Cable and connector:


I can't say I am a fan of either the connector or the cable. The 2-pin connectors used by MD4 are not recessed (best) or flushed against the shells (meh) but popped out from the shells similarly to 64 Audio universal IEMs. I'm not too fond of this design because it can place a lot of pressure on the metal pins. I fear I would snap off the pins and get them stuck in the connectors. Still, nothing has happened, and the connectors seem durable so far.



The cable is soft and good-looking, no doubt. However, it has three issues at once:
  • The QDC-like connector at the 2-pin side. These angled 2-pin connectors are annoying with KZ/CCA IEMs, 64 Audio IEMs, and MD4.
  • The pre-formed ear hooks have a very aggressive angle. They wrap tightly against your ears and curl around themselves when not being used (see the photo above).
  • The braiding of the cable makes it curl around itself automatically (see the photo above). This braiding is also used with ALO (campfire audio) cables and a cable from Dunu. I'm not too fond of any of these cables due to how tangly and generally unpleasant they are to use.

In the end, I tamed the cable by removing the ear hooks and stretching and twisting the cable until it softened.

Tuning switches:


MD4 has two switches at the back. They are not simply "treble" and "bass" switches but have a noticeable effect across the entire frequency response of MD4. If you are curious, I have a detailed breakdown of what these switches do base on measurements at the end of this article.

For simplicity, I would use two numbers to denote a switch configuration in this article. For example, "11" means both switches are switched to ON.

How it sounds


Listening tests were done with the following source chains:
  • (For A/B test) Android Phone / iPad Pro (Apple Music, Hiby App, YouTube) =(USB-C)=> Fiio KA3 =(3.5mm)=> Hidizs MD4
  • Android Phone / iPad Pro (Apple Music, Hiby App, YouTube) =(USB-C)=> Hidizs S9 Pro =(3.5mm)=> Hidizs MD4
  • Hidizs AP80 Pro-X =(3.5mm)=> Hidizs MD4
  • Nintendo Switch => Creative X1 => Hidizs MD4

Local FLAC files ripped from CDs or bought from Qobuz, and Apple Music Lossless were used for most casual listening and A/B tests. My test tracks can be found on Apple Music here.


Tonality and Timbre: 3.5/5 - Above Average


Frequency response of the "bass" configuration of MD4, which I used for all of this review. Measurements were done with an IEC-711-compliant coupler and might only be compared with other measurements from this same coupler. Visit my graph database for more comparisons.

When I saw the graphs of Hidizs MD4 for the first time, I was immediately interested due to their noticeable dip around 1.5kHz. This kind of dip appears in 64 Audio Trio, one of the most spacious IEMs I have heard. However, this tuning trick is a double-edged sword that can make an IEM sound hollow and unnatural. How well does Hidizs execute this tuning?


Midrange: My first impression of MD4's sound was not positive. In the default tuning ("balanced"), the IEM sounds unbearably stuffy and boxy. Vocal such as Ed Sheeran's in Shiver sounds dull and muffled. Not warm, but muted.

The culprit was the excess energy in the lower Midrange (250Hz to 500Hz) that created a "veil" all over the music. The ear-gain region was barely enough to pierce through the "veil". With some brain burn-in and suitable music, such as "Father and Son" by Cat Stevens, this sound signature might be desirable or even charming to some, but not for me.


Luckily, the tuning switches of MD4 bring about noticeable differences. The "treble" tuning (switch configuration 00) completely lifts the "veil" and extends the soundstage in all directions. In this configuration, the ear gain is pushed to around 13db above the lower Midrange, making it easy for midrange elements to cut through the mix. However, the strategic (accidental?) dip at 1.66kHz and 3.5kHz prevent MD4 from sounding in-your-face or piercing. Harsh recordings such as Shivers by Ed Sheeran are borderline shouty with MD4, similarly to Blessing 2 and other IEMs with Harman-inspired tuning.

If the "treble" tuning is too much, you can try the "warm" tuning (switch configuration 01), which flattens both the bass and treble by a couple dB. I find this sound signature closest to a "well-tuned" sound. However, the dip at 1.66kHz is not as pronounced, so the immersive soundstage imaging of MD4 is somewhat diminished.

My favourite tuning of MD4 is the "bass" tuning (switch configuration 11). It keeps the overall tonality of the "warm" tuning but brings the 1.66kHz dip back and reduces the ear gain just a touch more. The result is a pleasant, mostly natural, and spacious midrange. I say "mostly natural" because some vocals are still ever-so-slightly nasally.


Treble and air: Well done across all configurations. Sparkly and resolving, but not harsh or piercing. Cymbals and hi-hats cut through the mix but do not stab the ears. This effect might be due to the strategic dip around 6kHz.

The "air" frequencies of MD4 are competent but not outstanding. You can hear airy reverbs and decays around musical notes. However, the energy level in the air region does not reach the level of top performers, such as 64 Audio IEMs with TIA drivers.


Rating: Beside the boxy tuning of the default configuration, MD4 generally sounds natural and pleasant. The existence of the 1.66kHz, deliberately or not, adds a sense of spaciousness to the Midrange without making it hollow. However, I did need to jump through some hoops to reach that sound. Therefore, I knock half a point off the tonality of MD4, giving it 3.5/5 - Above Average.

Percussion Rendering: 3/5 - Adequate

Percussion rendering reflects how well the tuning and technical performance of an IEM work together to recreate realistic sound of a drum set. Good drum hits have a crisp attack (controlled by frequencies from 4kHz to 6kHz), full body (midbass frequencies around 200Hz), and physical sensation (sub-bass frequencies around 50Hz). Good technical performance ("fast" driver) ensures that bass notes can be loud yet detailed. IEMs that cannot control bass very well tend to reduce the bass' loudness to prevent muddiness.


MD4 has the typical bass response of BA woofers and sounds quite similar to Campfire Audio Andromeda 2020. This bass response lifts the region below 1kHz by around 5dB rather than having a distinct bass shelf from 250Hz. It means that the bass of MD4 sounds like a large "boom" rather than a tight and deep "punch".

Is this bass tuning wrong? Not really. Because bass notes tend to disappear faster with BA woofers, the bass response of MD4 still feels clean, snappy, and relatively impactful.

Let's dig into some test tracks to see how MD4 compares against benchmarks:

Dragonborn: MD4 produces a bit of rumble at the beginning of this epic soundtrack. Throughout the piece, it manages to reveal the tempo and rhythm of the underlying bass line. However, the drums lack grip and texture. They sound "boom" or "poof" rather than "brrrm". This lack of texture makes this soundtrack a bit mushy, as it has a lot going on in the bass region. It should be noted that my Moondrop Blessing 2 (3.5/5 - Above average) is no better in this regard. MD4 and Blessing 2 are easily outperformed by a fully-powered FF3 (4.5/5) or E5000 (5/5).

Despacito: The first bass notes at 0:10 are soft and smoothened on both MD4 and Blessing 2. However, MD4 lacks the large and sudden volume swing that Blessing 2 can create at the first bass drop at 1:05. Both MD4 and Blessing 2 lack the bass texture and top performers like FF3 and E5000.

Based on the above comparison, it is clear that MD4's bass is adequate for casual listening. Drums are rendered with decent weight and body compared to ruler-flat IEMs like ER2SE (2/5 - Not good). However, the bass is inadequate for folks who are picky about bass performance or require a lot of bass in their music. Therefore, I rate MD4's percussion rendering 3/5 - Average.

Resolution, Detail, Separation: 4.5/5 - Very Good


Resolution is a strength of MD4. Even with the less-than-stellar default tuning of MD4, I was still intrigued by how crisp and separated the IEMs render busy music. A/B tests against my benchmark IEMs further intensified rather than diminished my initial impressions.


Let's dig into some test tracks and see how MD4's resolution compares against Blessing 2 (4/5 - Good) and Andromeda 2020 (5/5 - Excellent):

G.O.A.T. by Polyphia: The difference in overall clarity and separation between MD4 and Blessing 2 is quite shocking in this track. MD4 sounds crisper, more precise, and more separated throughout the whole track. At the same time, Blessing 2 is splashy, blurry, and even congested when the music becomes busy. The contrast between closer and further away sounds is obvious with MD4 but ambiguous with Blessing 2.

Andromeda is still half-step ahead of MD4. "Effortlessness" is the key word here. Despite sporting a "thicker" tonality, Andromeda allows you to follow individual elements of the mix with little effort. In back-to-back A/B tests, MD4 feels a bit softer, less crisp, and less separated than Andromeda.

Summer by Janine Jansen and friends: MD4 again sounds noticeably crisper and more separated than Blessing 2. Even though Blessing 2 is no slough by itself, back-to-back A/B tests highlighted blurrier note attacks, more congestion, and surprisingly more grainy violin sound.

Again, Andromeda is still half-step ahead of MD4. Back-to-back A/B tests show that every instrument on MD4 has a little less detail and texture than Andromeda. The gap exists even when I boost the volume of MD4 to a loud level to take advantage of "louder is better".

Synchro (Bom-ba-ye) The hand claps at the beginning is an excellent test for the micro-details, treble resolution, and "air" of an IEM. MD4 passes with flying colour, revealing more nuances in the claps and slight reverbs and decays at the end of the claps. Blessing 2 is splashier and not as crisp. Is the difference day and night? Not really. Because MD4 and Blessing 2 are resolving IEMs, distinguishing nuances like micro-details requires careful listening.

MD4 vs Andromeda is ... interesting in this test track. The slight "air" and reverb in the clapping section are better (!) on MD4. Still, Andromeda separates the individual claps a bit clearer.

Based on the above comparisons, I rate MD4's resolution 4.5/5 - Very Good. It soundly outperforms my Blessing 2 and just half-step behind my Andromeda.

Stereo Imaging (Soundstage): 4.5/5 - Very Good

Stereo imaging or "soundstage" is a psychoacoustic illusion that different recording elements appear at various locations inside and around your head. Your brain creates based on the cues such as the loudness and phase differences between the left and right channels. Most IEMs do not differ significantly, nor can they compete with headphones or loudspeakers. However, some IEMs offer a more spacious soundstage than others. Best IEMs can create multiple layers of sound from closer to further away and make some instruments float slight above your head.


The soundstage imaging capability of MD4 depends significantly on the tuning configuration. To my ears, the default "balanced" tuning creates a tunnel-like soundstage: narrow but deep. This kind of soundstage reminds me of Fiio FA7s, which I found "uncanny". However, some folks find FA7s to have a massive soundstage, so the "balanced" tuning might work.


To get the most out of MD4, I recommend either "treble" or "bass" tuning. The "treble" tuning opens up the soundstage in all directions. The "bass" tuning - my favourite- shrinks the soundstage a touch compared to the "treble" tuning. However, it brings the 1.66kHz dip back, which works wonders in tricking my brain into thinking that sounds come from different distances or "layers" in the soundstage. I crave this "3D" effect.

Let's dig into a test track:

G.O.A.T. by Polyphia: MD4 does this soundtrack justice. Sounds pop up from all directions in the 270-degree cone in front of me. Some effects even pop up from slightly behind my ears. The sense of contrast in terms of distance is immense: some sounds are right next to my ears, whilst some blips and blops fade away in the background as if they come from the room. Back-to-back A/B tests show that Blessing 2 is flat, congested, and lacks the sense of 3D that MD4 can create.

Can MD4 challenge Andromeda's famous "holographic soundstage"? Nearly there. Both IEMs are neck-and-neck in terms of placing instruments on the stage with pinpoint accuracy, not just left to right but also closer to farther. However, I still think Andromeda is half a step ahead of MD4. The extra 8kHz energy of Andromeda helps with creating the illusion that cymbals and hi-hats come from above. Andromeda's more modest ear gain also makes the illusion of depth a bit more intense and convincing.


Based on the comparison, I rate the stereo imaging of MD4 4.5/5 - Very Good. I want to emphasise that this score does not mean that MD4 has the largest soundstage (that honour goes to Sony IER-Z1R). What MD4 does in that soundstage is what makes it great: Sound is rarely congested but layered from closer to further away with a clear contrast between near and far.


What makes an IEM "good"?

For me, it's all about resolution and soundstage imaging. Hidizs MD4 is unique because it achieves both at a modest price tag (in the "audiophile" world. It is still an expensive toy in the grand scheme of things). Sure, the bass performance takes a hit, and the tonality is not quite "audiophile-approved". However, if you crave that resolving and "3D" sound, MD4 receives a recommendation from this reviewer.

- Very good resolution
- Very good soundstage imaging
- Multiple tuning options to match your unique ears and library

- The default tuning does not leave a good impression (to me)
- The Midrange is still slightly unnatural due to the 1.66kHz dip
- Barely adequate bass performance


Appendix: What exactly do tuning switches do?

The left switch controls the frequency from around 1kHz. Turning it on dips this region by approximately 2dB and introduces a significant drop at around 1.66kHz.


The right switch controls the whole frequency response. Turning it on flattens the curve below and above 1.66kHz, making the dip less noticeable.

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Good review and great breakdown of exactly what the tuning system does. Diagrams on resolution/attack/decay and soundstage were also illustrative of concepts that get frequently thrown around and often misused.


Headphoneus Supremus
Pros: -Good imaging
-Good resolution
-not too agressive W shape signature
-fast attack speed
-tuning switch for adding warmth, bass or treble sharpness
-excellent construction
Cons: -slightly artificial tonality and timbre
-lack of note weight and natural resonance
-compressed vocal and mids
-rolled off and uneven bass
-treble can be distracting
-intimate soundstage

TONALITY: 7.2/10
SOUND VALUE: 7.5/10 (due to the tuning switch)


HIDIZS has been around since 2012 and are mostly known for their DAP and dongles offering, but they make earphones too! Their hybrid driver, the MS2, might be the one that get the most praise in audiophile community.
Today, i will review something different from them, the MD4, which is a 4 balanced armature IEM with a tuning switch that permit to have 4 different tonal balance.
Priced 190$, the MD4 use 4 custom BA of unknow model, have 3 way crossover and this very intriguing tuning switch.
Let see in this review if the MD4 can deliver appealing performance and charming musicality!



When it come to built quality, Hidizs rarely disapoint and here we have sumptuous design with excellent craftmanship. The built is both sturdy and elegant, with much of housing made of CNC allumium with a back plate made up of amber and gold lettering of the logo. This back plate is pure eye candy yet doesn’t feel over the top or bling bling. Glossy elegance made with taste.
And it’s comfortable due to organic housing shape, long nozzle and small enough shape.
2pin connector is perhaps the only part which could be improve, a recessed metal one would have been better to secure and guide connection.

The cable is very nice, it’s a 4 cores pure copper silver plated wires with 0.78mm 2pin. The ear hook is a bit too tight for me but construction seem durable.


When it come to packaging, that’s a quite generous one. It include 9 pairs of silicone eartips, a cleaning brush, a beautifull carrying case. It would have been nice to have the possibilities to choose between single ended and balanced cable like numerous audio companies do, alas, it isn’t the case.


(Gear used: Tempotec V6, Tri TK2, Moondrop Dawn and Questyle M15)

Tough the tuning switch did inflict on tonal balance, overall tonality of the MD4 go from warm W shape to sharp W shape where upper mids and treble is the more boosted.
Treble switch will add air and improve sens of imaging while warm or bass filter will smoothen attack edge, add a bit of lower mids warmth and just tiny bit of bass slam.

Honnestly i’m still waiting for an IEM with just one switch: Basshead and Crisp neutral tonality, something that really offer 2 different IEM instead of 4 slightly different sound dynamic presentation.

Bass is fast and gently boomy, with short sustain and resonance, it can offer a fuzzy sens of rumble, but the lack of proper edge definition make it a bit blurry in resolution-separation. BA bass is even a hint boomy with flagship IEM like the T800 that use 8 knowles BA, but here the boost is mostly in mid bass but have warm high bass too, so extension is rolled off and doesn’t dig deep, making bass line dry and foggy. We have fast non edgy punch, and warm to dry presentation depending of tuning switch choice, yet these aren’t for basshead nor bass lover.

Mids are crisp with smoothen edge, organic texture and decent transparency. They feel well layered too, and most of the energy come from upper mids which aren’t too agressive, but sometime can go shouty at high volume with bright source. With both male and female vocal, their a hint of breathyness to it, and timbre isn’t too thin for balanced armature. I mostly listen to female vocal, which are clean and centered, not very open and wide but smoothly bright with good texture and just very rare instance of sibilance, especially with Treble tuning. With Warm tuning switch, vocal gain a bit of timbre density and presence wideness and body. So I hear the mids to be lifted in lower mid which add meat and BA lushness, lean in mid mids and sharp in upper mids yet softed in dynamic loudness to avoid it getting too hot. Piano sound clean and clear enough, with impressive definition especially when the keys are hold so you even get sustain details but the release cut short as expected, yet, presentation have more energy than I expect, making fast jazz piano trio sound sometime very immersive since saxophone too sound very good. Are these made for jazz? Well, unless you wish to focus on bass player, I do think so.

Treble is fast and technical yet not very snappy and just a hint sparkly. The bite too is softed as say, so this affect attack lead and stole the air it should project after impact. In the other hand, it make the highs feel full and not too trebly or distracting, yet they have dense amount of sound info, just a bit darkened in crispness here. We have some brilliance nonetheless in upper highs and speedy attack speed as expected from BA. Treble tuning switch will add sharpness, some air and attack edge, yet it’s limited in texture micro nuance.
This is unique analytical treble section, which have concentrate sens of energy in lower and upper highs, sometime it can be a bit shouty because of this, while other time it will boost definition and dynamic of percussions section with good result. Yet, for my hearing, MD4 is the kinda IEM that is impresible in loudness behavior, so you can be tempted to raise or lower the volume depending of music type or dynamic mastering.


This is the good part to me, since MD4 is very capable in this department. Attack speed is fast with short sustain that permit to have good enough separation in imaging.
Resolution is generous in micro details and tend to extract them with enough precision, especially in not too complex tracks.
With fast busy track like ”Skink” for jazz rock band Elephant9, this short but blurry sustain-release show it’s limit and tend to go muddy-shouty.
Harmonic distortion do occur, and bass is borderline distorted at high volume or with sub bass heavy track, yet a gentle blur tend to warm these imperfection so it’s not that bad and overall sound is clean enough.
Spatiality isn’t the most open, but with eartips like Kbear KB07 its pretty wide and tall enough with decent deepnesss, just not very far from your head in spatial perception.


I will not turn around the bush too long about this: i’m not a fan of musical presentation of the MD4 and none of the tuning switch change my distant emotional response to them. These are very technical, yet safely tuned multi-BA…at the same time, while safe, pina gain is quite important and upper mid range can distract me from bass and highs. This mids-upper mids are damped in sibilance, thats good and bad since it affect definition clarity.
Vocal doesn’t sound open enough to me, they feel fowards yet compressed in middle of instrument. As well, timbre while a bit dark in texture isn’t very natural nor very bodied.
In term of dynamic, this is the type of IEM that favorize loudness impact over weight note heavyness and resonance, which is common in multi-BA IEM and not something i’m very afound off.
All in all, the MD4 have a romanticized clinical musicality to me.




The excellent Golden is more neutral and balanced, have a weightier sens of dynamic and note impact and fuller more present bass. The bass is dealed with a dynamic driver here, so even a cheap one will be superior to balanced armature in term of fullness, chunkyness, roundness and flexibility-elasticity of attack and extension. While the MD4 boom is more excited, it lack the well define authority and presence of the Golden as rumble density. Both quantity and quality is superior to me, definition too have more grip but separation is on par yet feel less artificialy detached than the MD4.
Mids are leaner and fuller with the Golden, less prompt to slight shoutyness and better define. Timbre is more textured and natural too. Sens of immediacy is higher with MD4 but more compressed-resonant in layering.
Overall treble is a bit sharper and more open airy with the MD4, while fuller and more organicaly balanced with the Golden.
All in all, Golden is a fuller sounding and better balanced MD4, with similar technicalities, yet a more natural tonality.

VS IKKO OH10 (1DD+1BA-160$)

Notably more V shape and bassy, brigther and more energic and open sounding too, the OH10 bass quantity and quality beat both Idun and MD4 here. Heavier chunkier hit, deeper more vibrant extension and better texture and definition as well as attack control and separation. Mids are brighter and more upper mids focus, female vocal have more dynamic presence and are more textured. Lower mids are thinner dryer with OH10. Treble is smooter with MD4, richer in layers amount with similar snap but perhaps more brilliance. Level of micro details feel higher yet sometime overly fowarded compared to better balanced OH10 in that regard.
Sounstage is more open wide with the OH10, deepness is similar but overall presentation feel more compressed and distant with MD4, yet hint more holographic too in a strange artificial way.
Imaging is overall superior with the MD4 due to higher amount of sound layers that are freely extract.

All in all, these 2 are very different in tuning, yet while both are no master of natural timbre, I do prefer the OH10 bassier and more evenly balanced musicality.



The Hidizs MD4 is a very interesting IEM with lot to love about, it’s highly revealing yet smoothed in edge to avoid agressive peak.

The tuning switch permit to add hint of warmth or treble edge as well as much needed bass weight when need. The construction is marvellous and overall tuning well balanced in it’s own unique way that will be hit or miss depending of your conception of musicality.

All in all, while i’m not charm by musical performance of MD4, i’m sure impress by it’s technical one whic offer a highly resolved sound with precise attack in treble and a sens of exciting immediacy that will be able to charm those audiophile seeking for well balanced analytical sound signature.


PS: I would like to thanks HIDIZS for sending me this review sample. I’m not affiliated to this company nor have been financially compensated. As always, this is my unbiased audio impressions.

You can buy the Hidizs MD4 for 179$ here:https://www.hidizs.net/products/md4?spm=..blog_bbe08951-c1d0-428e-bb7f-5553f37762ae.header_1.1

For more honest audio reviews, give a look to my NO BORDERS AUDIOPHILE website HERE.
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I love your idea for one switch, brighter or warmer, take your pick! Way better than "Would you like the red pill or the blue pill, or the funnily little green one, or the capsule with what looks like little M&Ms in it or..." :ksc75smile:
@Carpet indeed, as we say: ''too much is like not enough'', so just one choice between 2 very different tuning would be great. Dunu Talos seem to try this, but mids and bass stay the same, so im thinking more about something like 2DD+2BA+1EST where we have basshead and crisp neutral tuning choice...ah, we can driam, cant we?!

Headphones and Coffee

Previously known as Wretched Stare
4 in one
Pros: Looks fantastic, super well-made and accessories are plentiful as well as good quality. 4 tuning modes and a nice balanced and detailed signature
Cons: Sub-Bass is weak, mid-Bass lean, some would find it boring.

Let's cut to the chase. Yes, the package is impressive, it comes with a lot of good and necessary accessories. the build is top notch and looks so pretty. I like the stock tips and cable; the leather case is large and useful. Comfort is excellent as is isolation.

Bass: The lows are fast and detailed but lack impact in the Sub-Bass, mid-Bass has a decent kick and is neutral and well controlled. this is defiantly more quality than quantity.

Mids: are well represented and have a rich and warm tone, the level of details is above average and has an organic timbre, notes have good weight and vocals are natural and pleasant.

Treble: Is airy and has a perfect amount of sparkle and details without harshness. In my opinion it is well tuned and refreshing.

Soundstage: Presents with a larger than average field, the imaging is quite accurate and sounds very good on live performances.

Conclusion: The MD4 with its tuning and tuning switches make it unique offering, while it may not be for everyone, I for one have grown to like it, especially on the ifi Gryphon where it sounds very good to me.

Brief and to the point. I find your YouTube content good too. :L3000:


1000+ Head-Fier
Organic Technique
Pros: 4 tunings for the same price. Plus extra tuning with the various tips as standard.
- Organic and analytical sound, a good mix.
- Great presence of all bands, generating a sensation of a wall of sound, full, wide, ample, solid, complete and musical at the same time.
- Remarkable definition, resolution, clarity, transparency, separation and amount of air.
- Very good packaging and quality of accessories.
- Great relationship between design, construction, beauty, ergonomics, level of fit and isolation.
Cons: Different and daring tuning (It can be an advantage or a disadvantage).
- Cable with balanced connection cannot be chosen.
- Pushed to the limit (high volume and bass-saturated music), the low end may suffer, generating a certain feeling of distortion.

There is no doubt that Hidizs (the well-known audio brand founded in 2009 by Tamson) follows a straight and determined path. It became famous for pursuing the best quality/price ratio in its DAPS, seeking as an absolute premise, the best sound, thanks to its professional audiophiles in its R&D department. After a few years and with several models under their belt, they thought of creating IEMS as well. Until the present day, this progressive development has led them to present the model that I am now going to analyse. It is the Hidizs MD4. As you can see from its name, it is an IEMS with 4 BA drivers designed and customised by the brand itself. They have a double switch to select 4 different tunings and a 3-way frequency divider. The body is made of multi-metal. It has a high precision 3D printed straight acoustic sound tube. It is fitted with a high quality 4-strand cable with silver and OFC wires on a 2Pin 0.78mm gold-plated connection. It is available in 3 beautiful colours, black, white and indigo. Its outer face exhibits a marbled pattern to match the body colour. Naturally, Hidizs accompanies the set with a careful staging, packaging and quality accessories to elevate the premium feel of the product. Let's take a look at the rest of the qualities of this great product.

Hidizs MD4 01_r.jpgHidizs MD4 02_r.jpg


  • Driver Type: 4 BA drivers designed and customised by the brand itself, 2 for bass, 1 for midrange and 1 for treble.
  • Frequency Response: 20Hz-40kHz
  • Sensitivity: 102±1dB@1kHz
  • Impedance: 8Ω @1kHz
  • Power rating: 3mW
  • Construction: Aluminium alloy body, CNC fabricated; rose gold centre frame, handmade celluloid faceplate, aluminium alloy output nozzle.
  • Jack Connector: 3.5mm SE
  • Capsule Connection Type: 2Pin 0.78mm gold plated.
  • Cable: Four 4-strand mixed braid, 2 strands made of high purity silver wire and 2 strands made of OFC wire.
  • Cable length: 1.2m in length.
  • Approximate weight: 14±0.3g, excluding cable.

Hidizs MD4 03_r.jpgHidizs MD4 04_r.jpg


First, I should comment that the colour of the reviewed model is black. The box matches this colour and is an almost cubic package, which on its upper side shows a realistic photo of the capsules, with the cable in place. Its dimensions are 125x125x92mm. In the upper left corner is the Hidizs logo inscribed in gold. At the bottom left is the model name and a short description. At the bottom right is the Hi-Res Audio logo. On the back side there are two columns: the left column is written in Chinese, the right column in English. You can read the specifications, the contents of the box, a schematic with the position of the switches and their corresponding frequency responses, and the brand's markings.
When the box is opened, the capsules are encased in a dense, black foam mould, lined with a dark cardboard cover with the model name and a slogan inscribed in gold lettering on the bottom. Once this first layer is removed, there is another mould containing three sets of silicone tips and a tool for cleaning and moving the switches. The third layer consists of a square box, with rounded corners, made of brown leather, on the top of which is the brand's seal. The complete contents are as follows:

  • 2 MD4 capsules.
  • 1 x 2Pin 0.78mm cable and 3.5mm SE plug.
  • 1 brown leather carrying case.
  • 3 pairs of white silicone tips, with vocal enhancement.
  • 3 pairs of black silicone tips, with bass boost.
  • 3 pairs of white silicone tips with black core, balanced.
  • 1 cleaning brush.
  • 1 user manual.
  • 1 warranty card.
  • 1 explanatory card with the modes of the switches and their FR.

What I like about Hidizs is that they design a compact packaging with a great content, a high quality and very attractive box, as well as 3 pairs of silicone tips, which allow you to fine-tune the sound of the MD4 even more. I can only miss some silicone tips, to be very strict.

Hidizs MD4 05_r.jpgHidizs MD4 06_r.jpg

Construction and Design

It is clear that the entire design and manufacture of each capsule is complex and laborious. Starting inside, there are 4 BA drivers customised by Hidizs. Two are dedicated for the lower range, one for the mid-range and one for the upper range, up to an extension of 40kHz, resulting in a Hi-Res certified sound. The internal audio transmission structure has been redesigned to house the drivers. A straight, high-precision 3D printed acoustic sound tube ensures a continuous and clean audio output. The entire body allows for increased sound effectiveness, reducing distortion and magnetic resonance. Each capsule incorporates a precise 3-way frequency divider, which helps to harmonise and balance each sound range.
Two micro-switches allow 4 different tunings to be achieved, enabling quick switching between high and low impedance.
The external construction of each capsule consists of 4 parts. A handmade, laser-cut and hand-polished celluloid outer plate with a marble/amber finish. The centre frame is a CNC machined piece of gold-coloured, rose-gold aluminium alloy. The output mouthpiece is also made of aluminium alloy and the body is constructed of EU IIA certified medical grade resin for the skin.
The shape of the outer face of each capsule is the classic African continent silhouette with stylised apex. Both the outer plate and the inner body are black on my model. The metal parts (outer rim and mouthpiece) have a golden-pink colour, which I prefer to call golden champagne. The IEMS are not very big, rather medium-sized, but their body has a thick rim, which houses the micro switches. In the space between them and the plastic base containing the 2Pin 0.78mm connection, next to the frame, you can read the brand name and a mole indicating the channel in white letters. The inner side is smooth, with a soft micro-sandblasted surface, no holes and an ergonomic shape, but with very light protrusions. The aluminium alloy mouthpiece has three levels, a small initial ring, a narrower and longer central cylinder, a slightly larger outer ring. The largest diameter is 6mm and the smallest 5.4mm. The protective grille is also made of metal and has micro-holes.
The cable has the classic Hidizs parts and is the same as the MM2 model. The 2Pin connectors of the cable protrude on a smooth surface, consisting of a translucent, angled sleeve. Each sleeve has a coloured dot (red or blue) to identify the channel. The cable, up to the sleeve, is made of two coiled strands and is sheathed in a semi-rigid, transparent plastic, which gives it an over-ear shape. The jack connector is the same as the cable of its siblings MM2 and MS2. The plug is 3.5mm SE gold-plated. The connector sleeve that covers it is a 19.5mm long cylinder with a diameter of 9mm, which is made up of 4 pieces. The first and closest to the connector is black, almost 14mm long. Then there is a beautiful copper ring, just over a mm long. Again, there is another black cylinder, on the inside of which is written the name of the brand. This piece is not movable and does not rotate. Finally, the top ring is again copper, in a colour that I like much better than gold. The dividing piece is simpler and is a relatively small black metallic oval piece. The pin has a similar shape, but is half as small and is a pinkish copper colour, like the pin sleeve parts. It is worth noting that the pin does its job perfectly and allows the cables to be fixed without slipping out of place unintentionally.
The cable consists of high-purity oxygen-free copper (OFC) and high-purity silver wire, stranded from 60 wires respectively. They all form 4 coiled strands, with one pair being a dark golden colour, while the other is more silver.
On this occasion, the design is somewhat more classical in its form, but not in its content. I think both the internal and external design are excellent, very neat, very beautiful and attractive. All three colours look highly elegant and I like them all. My only drawback is that such a nice cable does not have a balanced plug.

Hidizs MD4 07_r.jpgHidizs MD4 08_r.jpg

Adjustment and Ergonomics

A more classic shape contributes to simpler ergonomics that are also more proven and efficient. Hidizs returns to a semi-custom design with a medium size, smooth and soft inner body, with hardly any protrusions or anchorages. The mouthpiece is medium and a deeper insertion could be assumed, but the diameter of the mouthpiece prevents this, unless other tips on the market are used. With my large foam-filled tips, I get a very high seal, a very firm and durable fit, and a very occlusal fit that promotes great isolation. The rotation is small and the firmness is high, the set is suitable for daily and outdoor use, it is very insulating.

Hidizs MD4 09_r.jpgHidizs MD4 10_r.jpg



I have to be honest and say that I found the graphs a bit strange. It is a two-zone profile, almost split at 2kHz. The first half is a rounded curve, slightly excited in the mid-bass. The level of sub-bass will depend on each tuning, as well as the linearity of this half. Before reaching 2kHz there is a valley which is more or less pronounced, depending on the position of the switches.
The second half starts with a double-peaked growth curve towards the high-mids and first treble, and then gradually and smoothly descends towards the inaudible high end.
The jump between the first and second half is very obvious and large in dB, augmented by the valley just before the jump in some tunings. Not so big is the downward jump after the first treble. Actually, this upper zone is quite common in all tunings and what changes is the emphasis on the rest of the curve. You could take the 10kHz as a junction reference and in that way you could see, perfectly, the differences of each profile. And this is what the frequency responses actually offer. Between one tuning and another there is not only a change of profile, but also a change of volume, as a result of the change of impedance that the switches generate.
All these characteristics led me to expect a rather polarised sound. Well, the final mix is better than the graph shows. But, it is true that it is not a common tuning, at least, from my point of view. But I can't give a profound opinion either, because I am only a reviewer, not a tuner.
Here is the result of my measurements and the comparison provided by Hidizs.


It's difficult to decide on a tuning. As a good bass-lover I always tend to start with bass tunings. I find that it can satisfy me on occasion, but I find an emphasis on mid-bass beyond my preference. I tend to lean towards a higher sub-bass boost and a cleaner, descending mid-bass. On the other hand, this is not an obscure tuning, and the MD4's profile is quite technical, with a certain analytical edge. Without losing too much bass, but linearising the area and the transition between the first and second half, the warm tuning is the one I have used the most. It is not without clarity and I think it has the best overall balance. The treble tuning is also consistent and will be the best technical level of the ensemble. Whereas I find the balanced tuning blander and the valley between parts more pronounced.
Most of my impressions have been taken with the warm tuning, unless otherwise specified.


The Hidizs MD4 uses a dedicated dual BA driver for the low end. Its profile is biased towards the mid-bass and, although it has depth, the incidence of sub-bass is not very pronounced. Generally speaking, BA drivers tend to colour the bass response, giving rise to a different vibration than a dynamic driver. In this case, this statement is still quite valid. The sub-bass is produced as a coloured oscillation. But the 40Hz point sounds fairly realistic. From this point on, the pure tones return to the BA sound I am familiar with. You can't judge a BA driver, two in this case, by the pure tone test. But it is a test to visualise its performance and realism.
The execution of the bass is fast and agile. It gives a good punch, but the air movement is not very large. This detracts from its credibility, realism and energy. Although the impact on the sound is clear, in order to remain, the lower range is stretched towards the mids. In this way, the lower range has adequate body and density, generating good volume throughout the range. Although this can be a danger in the transition, more pronounced in the low tuning, while in the high tuning, this effect is much more controlled. In warm tuning this effect is somewhat minimised, but maintains a characteristic warmth. Hence, of course, the name of this setting. Although the effect persists, you can live with it, and I find it quite pleasant. The technical ability of the MD4s contributes to a better transition than the same tuning with a dynamic driver and the speed of the set manages to untangle the mix.
Back to the sonority, the lower bass drums are quite rounded, smooth, with a point of projected energy, limited power, quick recovery and no aftertaste. The colour and intrinsic BA properties detract from a certain depth, viscerality, the sensation is less physical and sensitive. Clearly, bass-lovers may miss these qualities that dynamic drivers do provide. By contrast, the MD4s make up for these shortcomings with a special, descriptive roughness. The timbre is not the most accurate or pure in the sub-bass area, but the texture is remarkable. Thanks to the agility of the drivers, the bass has good layering, is well defined, does not mix and disperse frequencies easily, as well as generating planes with simplicity and has the ability to define complex passages, without mixing or blurring the rest of the sound and without losing the thread of the bass. In this respect, the level of resolution is remarkable, and clean, well-recorded electronic genres are reproduced with quite good technical class, which makes the sound more dynamic and allows the rest of the sound ranges to shine.
I would have preferred a tuning more inclined towards the sub-bass, but I think that for BA drivers it can be a more complex task, in this price range. Finally, the energy level they can withstand is high and the performance is clean at certainly high volumes. But they will never hold as much as a dynamic driver, so that's something to keep in mind.

Hidizs MD4 11_r.jpgHidizs MD4 12_r.jpg


If the bass has a colour that detracts from its purity in the lower frequencies, in the mid-range we are on the other side of the coin. It is here that the MD4s express their most realistic and faithful level of realism and fidelity, as well as generating a vast, but well-spaced and airy body mass. I could say that the MD4s' midrange sound is organic, very natural for coming from a BA driver. I think I have to swallow my initial thoughts about the frequency response and acknowledge that the result is very good in this midrange. In addition, the incidence of the switches, as well as the tips used, allows us to adjust the tuning to our liking. To begin with, the first half of this range is very well represented. In the warm position I like the body of the male voices and the density of the instruments. The timbre is very appropriate and that is part of that organic character, mixing an analogue point with analytical nuances. This combination creates a particular sound, while the tuning enhances the mass, bringing it closer to the listener and filling the scene. I have to admit that the sound is very big, full, intense, but never crowded or heavy. There is no darkness, no attenuation. You can even get a more neutral mid-range, which can never be blamed for a lack of homogeneity or balance, although it may seem otherwise. And I am referring to those mid-highs that I might have feared. It is true that the jump exists and the warm tuning brings the levels closer together. But I must surrender to the evidence and discover, with pleasure, that the FR does not reflect the reality as I thought it did. I thought it was going to be more intense, brighter, more uncomfortable, more uneven. However, it is much better. I can't say that it is a totally balanced strip either, but the result is well compensated. And again I appeal to the switches and tips to adjust the result. Both halves of this stripe complement each other, they don't fight each other, they don't overshadow each other, they don't overlap. Rather, everything flows in the same direction and under a premise of mutual respect and synergy. The first part offers body, mass, density and the second, exuberance, clarity, transparency, sparkle and vigour. The result is a great symbiosis ready to be enjoyed by the listener.

Hidizs MD4 13_r.jpgHidizs MD4 14_r.jpg


This mix of organic, analogue and analytical character persists in the high end. The treble may stand out more or less, depending on the selected tuning. But everything is kept in check and well placed. It may seem that the sound is more vivid, both in the mid-highs and in the highs. That's why I use the warm tuning. But you may also want a brighter representation for some occasions. That's what the switches are for. So it's great to be able to activate them at will. The result is not long in coming and it is worth remembering that the character of the MD4 is never lost in these combinations. The upper zone is descriptive, with a good energy point. The notes are not completely thin, but have a subtle softness that gives them a certain thickness. The level of resolution, however, allows their representation to be precious, with a point of delicacy, well outlined, with visible and palpable edges. In this way, the trebles are well modelled, keeping their naturalness, without losing any sparkle or air. The tapering extension redesigns a new control zone, and this is another success in the tuning of the MD4s. The top end is not very high, but the technical capabilities of the drivers act to help the projection of this zone to be adequate.

Hidizs MD4 15_r.jpgHidizs MD4 16_r.jpg

Soundstage, Separation

I find the scene vast yet frontal, as if it were a wall. And it is a big, high wall, which looms overhead. There is a close presence that lifts the sound almost overhead. That's why there is a good ethereal feeling, but also because of the excellent separation, amount of air and the analytical capacity of the ensemble. The laterality and stereo feel is also very appreciable and this is helped by the explicit positioning of details: it is very easy to locate nuances and small musical features. There is space between notes, air, a good dark background, more than enough resolution to discern where some elements end and others begin. The only thing I could miss is a greater depth: the grandeur of the sound and the proximity work against a clearer expansion on the longitudinal axis. Although, I must conclude that the generation of planes and layering of sounds is pleasing and insightful.
Needless to say, the recreation of the scene is realistic and obvious, without getting out of one's head, but generating a good holographic feel, thanks to the remarkable layering and stratification qualities already discussed.
At the limit, micro detail exists, but without becoming critical, cold or too clinical. It is remarkable, but not superior.

Hidizs MD4 17_r.jpgHidizs MD4 18_r.jpg


BQEYZ Autumn (Normal)

I like to compare IEMS with similar profiles. But on this occasion, I found it difficult to find a similar frequency response. In the end, I have decided on a great model. This is the BQEYZ Autumn with normal filter. It is a single Dynamic Driver with a system of interchangeable magnetic filters (three), which offer a great level of detail, musicality and performance in all bands. Undoubtedly, this is a premium model on a par in design and construction, very attractive as well. Only the Hidizs' level of accessories would be superior, although I like the Autumn's cable better, and it can be chosen in three terminations (2.5mm BAL, 3.5mm SE, 4.4mm BAL).
From the outset, the sound is different. The different profile is instantly noticeable. The Hidizs are more sensitive and possess a greater frontality across their entire spectrum. Their close, almost overhead mids contrast with the Autumn's more relaxed sound. You feel the deeper, more natural and realistic sub-bass of the BQEYZs, with the low end being more linear and cleaner. The MD4s' bass is more restrained and compact, faster and more fleeting in its recovery. There is a more natural and realistic elongation in the BQEYZs, and they are able to withstand higher pressure without suffering. The mid-bass of the Hidizs, more swollen, also exalts the first part of the mids, being more dense, full-bodied, close, present and big. In this same zone, the Autumns are thinner, feel more delayed and need more power to gain physicality and find more balance with the Hidizs. The MD4s offer more immediate, undemanding performance throughout the midrange. Their sound is wider, closer and more evident. The Autumns are thinner in the first half and this is noticeable in the body of the male voices. Their mid-high tuning seems more delicate, less aggressive. While the Hidizs persist in the evidence, even in the details, being more analytical and explicit. The timbre shifts from one to the other. The warmer tuning of the MD4s is noticeable in this position, while the normal tuning of the Autumns is more neutral. Both have a great ability to extract detail, only the MD4s have a more prominent and palpable ability, while the Autumns offer an almost similar performance, but with a more forced performance: just as the bass reproduction of the Hidizs is more critical, because their drivers lack the suffering ability and dynamic driver performance of the BQEYZs, so it is with the mid-highs and highs of the Autumns. These generate a good performance, but everything seems simpler and less forced in the MD4s, which have a greater expressive facility in this phase than the Autumns. The BQEYZs also present the details, but perhaps at the cost of a more incisive sound, while the Hidizs have managed to blend smoothness and analytical ability.
There is a critical point with Hidizs: when playing bass-heavy electronic music, with very detailed mids and very defined highs, they are able to discern very well in the mids and highs. But bass tends to suffer at the limit, if you enjoy it at high volume. There is more control throughout the range in the Autumns, but you feel a sharper and more penetrating upper-midrange and early treble.
The Autumn's soundstage is deeper and more oval, with good laterality, but it's smoother and more vaporous. Whereas the Hidizs stand out for their wall of sound, closer presence, higher pitch and a slight point of better separation and amount of air. But at the end of the day, it's a different staging in both IEMS: it's like comparing a dense, wide plane (Hidizs), with a semi-oval (Autumn).



OK, I know that graphs don't say everything about the sound. But in this case, the example is even clearer. The FR of the MD4s surprised me at first, because it was different and not very homogeneous. But once you put it on, it is neither one nor the other. The sound is much better. Except for the classic BA-ness of the low end, there is an effort to recreate bass in the best possible way, within its price range. To hardcore bass-lovers and electronic music lovers, they may still be a little coloured. But for all other music, such an effort is remarkable. In the mid-range there is no doubt, the tuning works: the speed of the drivers, the great technical capabilities, coupled with a great mix between low and high mids, generate an excellent range, close, full, wide, big, detailed, clear, transparent, quite natural and with a good timbre. All this, without losing neutrality or fidelity. The treble is no slouch and maintains the level without being critical or too bright. Hidizs has generated a good tuning with them and a drawing that unites control and sparkle, to vitalise the sound. Finally, that synergistic union of organic and analytical sound delivers a big, loud, ethereal, spacious and very well-defined scene.
The final touch is a compact presentation, with good accessories, both in quality and quantity, and an elegant, luxurious, comfortable, ergonomic design, with three pleasant and attractive colours.
As a final point, the Hidizs MD4s win when compared. At first glance, the sound may be relatively good. But when you go back to other models, you realise that they are better and you start to miss those features that you didn't see as virtues at first. And you don't experience that with just any model.

Hidizs MD4 19_r.jpgHidizs MD4 20_r.jpg

Sources Used During the Analysis

  • Hidizs S9 Pro.
  • Hidizs AP80 PRO-X.
  • S.M.S.L Sanskrit 10th MKII + iFi ZEN CAN.
  • HiBy R3 Pro.
  • Earmen Colibri.
  • Earmen Sparrow.
  • xDuoo Link2 BAL.
  • Tempotec V1-A + Hidizs DH80S.
  • Tempotec Sonata HD V.

Hidizs MD4 21_r.jpg


  • Construction and Design: 93
  • Adjustment/Ergonomics: 92
  • Accessories: 93
  • Bass: 72
  • Mids: 93
  • Treble: 91
  • Separation: 92
  • Soundstage: 92
  • Quality/Price: 87

Hidizs MD4 22_r.jpg

Hidizs offered me this model, in exchange for writing an honest review. I want to make it clear that all my opinions written in this review have not been conditioned by this fact, nor will I ever write anything that I do not really think or feel here. I will only write about my personal opinion in relation to the revised product.

Hidizs MD4 23_r.jpg

Purchase Link

Hidizs MD4 24_r.jpg

You can read the full review in Spanish here

Hidizs MD4 25_r.jpg
Nice review. I'm also a sucker for IEMs with unusual tuning (that works). This IEM seems like a well-priced addition to the market.
Good review.
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100+ Head-Fier
Hidizs MD4 Review - 4 Sound Sig for the price of one?
Pros: Balanced sounding with various tuning modes
Versatile and able to switch sound signature anytime
Very easy to drive
Natural sounding timbre and also good technicalities
Cons: Bass might be lean for some (Not for me as i'm not a basshead)
Certain tuning mode made the vocal slightly recessed

Hidizs was founded in 2009,and since then,they have been producing high quality products which garnered a lot of positive feedback from fellow audiophiles.Today i have the MD4 with me,it is a 4 custom balanced armature developed and tuned by Hidizs.One BA for the high frequencies,one BA for the mids,two BA for the lows.

On top of that,you also get 4 types of tuning which is adjustable via the switches on the IEM itself.This is all done via electronic crossover.

Premium,premium,premium!I have to say it thrice because it looks very premium.
Upon unboxing the MD4,I am greeted with an abundance of eartips,in fact,three types of ear tips all with three sizes,so there isn’t a reason where you can’t find a suitable size for your ears.

The brown storage case has a “leather-ish” look and it feels very sturdy and classy looking. I am very sure whichever IEM you store inside,they are bound to have good protection from the storage case.

MD4’s build quality is superb,from the unboxing experience until holding the IEM,it screams premium all the way!The faceplate is handmade according to Hidizs,the frame is made out of aluminium alloy with rose gold framing,even the nozzle itself is using aluminium alloy as well.There is certainly nothing that seems or looks cheap on MD4.

The shell size is slightly bigger than most of the IEMs I own,but in terms of fitting and comfort wise,I have no issues with them at all,comfortable to listen to for several hours without feeling discomfort,no weird edges that cause discomfort to my ears.


Foobar2k -> TRI TK2 -> MD4
Tidal -> Questyle M15 -> MD4
Hidizs AP80 Pro-X -> MD4

Sound (Based on Warm tuning with FInal Type E eartips)
I personally liked how the warm tuning gave me a good sense of balance between musicality and details. To me,it is slightly colored yet the detail retrieval capability is there and not compromised.It sounds pretty organic to my ears.

  • Bass is fast and tight,evident in Alice Cooper’s Go To Hell,the kick drum has got good thump and texture to it,certainly not thin sounding
  • In terms of speed,it exhibited good performance in Slipknot’s Duality,no problem keeping up with the speed of the drum
  • Sub bass perhaps is the weaker part of MD4,slightly rolled off,definitely not for basshead nor listening to EDM,you can still listen to EDM but you will miss the “fun” factor as the rumble is not that much
  • Overall,i like how the bass is tuned and it is nicely done and not overly emphasised nor rolled off
  • Vocal’s positioning on warm tuning is somewhat intimate and very pleasant to listen to
  • Male vocal and female vocal has got good texture and organic sounding on warm tuning mode,i find them to be very pleasant
  • Instruments in this range has got good note weight and the timbre is realistic
  • The lower mid range is lush sounding on orchestral track and the upper mids are tuned right to my ears and it’s not harsh/fatiguing to listen to
  • Safe to say,sibilance and harshness is not something you will find in MD4’s warm tuning mode,even on treble’s tuning mode
  • The treble on warm tuning mode is smooth and has good speed and good note weight
  • On warm tuning mode,i am kinda surprised to hear that it also has a good amount of air and sparkle to it
  • Instruments in this range does not sound harsh and very pleasant to listen to


  • I am actually quite surprised that the soundstage on MD4 is good given that it has no vent at all and using a straight tube design,but do take into consideration that the eartips that i am using might be contributing to this bigger soundstage perception that i am having
  • Soundstage of MD4 has good width,which i perceive as slightly out of head and good height as well to complement to this big soundstage that i heard from MD4
  • Imaging is no slouch either,instruments can be pinpointed easily even on complex track such as Slipknot’s Duality and some orchestral track

Comparison between different tuning modes (Listening to the same track RHCP’s Black Summer on all modes)

  • On this tuning mode,everything seemed to sound forward and intimate
  • In terms of tonality and timbre,they are more or less the same as warm tuning mode
  • Note weight remained the same
  • However i do notice that the vocal seemed to sound a little bit pushed back despite everything else has been brought forward
  • Imaging capability remained the same but soundstage is more in your head rather than wide but still retaining good sense of height

  • The vocal positioning is similar to warm tuning mode
  • As the tuning mode suggest,the low end has been slightly lifted to give the extra thump,however it is still nowhere near basshead level but it definitely add some fun factor to the listening experience
  • It is slightly darker sounding compared to the other two modes earlier,the treble response is smooth and non fatiguing
  • Both male and female’s vocal texture sounded a little thicker
  • Soundstage rendition is similar to warm tuning mode

  • Strange that the vocal positioning is similar to balanced tuning mode,it seem to sound a little pulled back
  • Soundstage is similar to balanced mode
  • As the name suggested,the highs are slightly boosted to give a perception of more details but it is nowhere near analytical of course nor fatiguing or harsh to listen to
  • Bass is fast and tight,punchy but of course lacking some of the impact from both the warm and bass tuning mode

  • MD4 is very easy to drive being a pure BA set
  • It is not picky in terms of source,they seem to pair well with both TRI TK2 and Questyle M15
  • Doesn’t seem to benefit from giving it more power
  • It will sound good even from Apple’s Lightning Dongle,but of course it does better job when paired with better dac/amp

Final Thoughts
To me personally,MD4 is not some IEM that wowed me upon first listen,it is something that grew on me,as i listened to it much longer,i grew to like its versatility that it offers in terms of the tuning switches.The tuning switches does actually impact how the music sound by altering the frequencies response via the crossover based on the input from the switches.

This to me is a big win as I am getting four kinds of sound signature which I can switch whenever I want,but I am sticking to the warm tuning mode as it is my preferred sound signature paired with my setup.A recommended set overall for anyone that’s looking for versatility!

*MD4 is sent over by Hidizs F.O.C in exchange for this review.I am in no way influenced by Hidizs to produce this review nor do i receive any compensation for this review

If you are interested in getting a pair of MD4,head over to the following link
Hidizs MD4

Cons: Bass might be lean for some (Not for me as i'm not a basshead)
So that makes you a treble-head "Wot are proper audiophiles"? Try not to be condescending in making references to other peoples preferences. "I'm" not "i'm" and "bass-head" will also help in not offending your spool chucker.

There isn’t a fixed definition to what is an audiophile, there are a lot debate to it but I’m not gonna go into that.

I’m not a treble head nor bass head and also I’m not condescending in making any references other than merely stating what I think.

If you’re offended, feel free to pass :) peace out @Carpet


Reviewer at hxosplus
The Chameleon
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.

About Hidizs

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.


Hidizs MD4

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.


Technical highlights

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.



Associated gear

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.


Listening impressions

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.

Test playlist

Copyright - Petros Laskis 2022.
Last edited:
Dunu Falcon Pro etc.
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What does the Hidizs SE Pro do for this set up. I see it connects to the type C plug which seems like an advantage, as in less change of damage to headphone jack. I am waiting the arrival of the MD4 earphones to go with my Hidizs AP80 PRO-X. Appreciate your review. Thanks

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Thank you.
The Hidizs S3 Pro is a good USB DAC dongle for enhancing your listening experience when you are on the move.
The AP80 PRO-X is of higher sound quality.


500+ Head-Fier
Hidizs MD4 - Switching The Way to Great Sound
Pros: -
- Big open sound, natural and fluid, highly organic
- Close to neutral sound curve, well balanced
- Highly user configurable tuning switches
- Great technicalities
- Comfortable usage despite being larger than most IEMs
- Premium packaging and accessories
Cons: -
- The shell may be larger in size for some ears
- Does not include stock foam tips (just silicones)
- Soundstage width not as wide as top tiered IEMs


  • This unit was provided by Hidizs for review purposes
  • My MD4 has undergone over at least 200 hours of playtime
  • I don't do measurements, I just describe what I hear, from my own POV
  • I don't use EQ
  • The entirety of my impressions was done with my own Foam Tips
  • Ultimately, my reviews are purely subjective and biased to my personal preference in sound
  • CEntrance DACport HD
  • Cayin RU6
  • NotByVE Avani
  • LG V50 ThinQ
  • HiBy Music Player (USB Exclusive Mode)
  • FLAC Lossless Files
The Build

Right off the bat I was impressed with the packaging of MD4. My unit came with an arsenal of tips selection and some accessories which will prove useful for longevity of usage.

As with the common practices for IEM of this pedigree, MD4 comes also with premium SPC cable made of 60 high-purity silver wires + 60 high-purity oxygen-free copper in twist braid formation. The cable itself terminated in 3.5mm Stereo Plug which actually looked so cute for being bantam length and adorned with gold circles. Hidizs official website does not mention the option to select 4.4mm or 2.5mm BAL options, however for my own usage, 3.5mm is more than enough. The IEM side termination uses classic 0.78mm pins, QDC style.

One thing that I wished Hidizs could have done better, please include at least a pair of foam tips....pretty please? I have never been able to wear silicone tips as they seem to impart odd resonances and reverbs to my hearing ability. Foam tips does not have that sort of anomalies.

Wearing the MD4 will require a bit of adjustment. I think the shells are slightly larger than most IEMs that I am familiar with. Similarly sized to SeeAudio Bravery and perhaps only the duo of 7Hz Timeless and Eternal are bigger. Once adapted, I was pleased to find out that despite the size, comfort was present and listening to MD4 for hours on end proved possible. No wear fatigue or complaints from my ear cavities.

Housed inside the slightly larger than usual shells, four custom tuned Hidizs Balanced Armatures with 3 way crossovers and a pair of tiny dip switches to allow the user to toggle for 4 different tuning. The switches can only be flicked with small pointy devices like a Phone Sim ejector....or needles.

Amazingly, MD4 comes with just 8 Ohm of Impedance rated at 102db of sensitivity. The first time I looked at this spec I told myself this one going to be one easy IEM to drive....or is it? haha

Tuning Switches

Let's have a look at the tuning switches a bit more. These sort of options most of the time can be seen on top tiered multi drivers or hybrid IEMs. At the price point of MD4, I think it is quite a luxury option to have - provided that the switches perform as intended. Well I am happy to say that the switches does work!.

As can be seen in the pic above, there are four selectable tuning:
- Balanced
- Warm
- Treble
- Bass

After spending some time fiddling with the switches, I settled with "Treble" option. To my ears that tuning set offers something which I regard as properly balanced without sacrificing upper range sparkle and shimmer. However, I can imagine that for users that are more Treble sensitive, may find the Balanced set to be a bit more dampened on the upper frequencies brightness. Frankly, I personally don't like the sound of both "Warm" and "Bass", they just sounded too colored and dark for my taste - I am a Diffused Field Neutral junkie after all and the "Treble" option is just right for me. Despite being labeled as Treble, it actually offers great balance from one end of the spectrum to the other end. I will talk more on this later. Suffice to say, this feature Hidizs bringing into the price point of MD4 is something very welcoming. Few years ago, this sort of feature would cost us in the region of over $500....

Sound Impressions

The entirety of my sound impressions were done with "Treble" setting and my own Foam Tips.

Sound Impressions



I would describe MD4 as a W curved sounding unit. What my ears telling me, the Lows, Mids and Highs exhibiting mild elevation that still edges closer to neutral territory. What's more important, they are very well balanced.
MD4 exhibited great organic timbre despite being an all BA outfit. Perhaps most important, I can clearly sense good coherency between the four drivers, all behaving in harmony to project fluid and mature dynamic transients. Dynamic vibrancy is amply fun as it is polished - no hint of overdoing it. I also observed that for some genre, especially Jazz and Bluegrass, the Mids would appear slightly more pronounced as compared to when listening to Rock/Indie recordings. Perhaps this indicate how transparent is MD4 with reflecting the mastering curves recorded in those songs.
Tonal wise, MD4 lived up to my expectations of being realistic. Attack, decays and transient interchanges appeared natural with no unrealistic aggression or prolonged decays.



Neutral is the theme for MD4 Mids. I must say that being neutral, MD4 will only serve to present what the sources fed it with. There's no hint of aggressive coloration of Mids being overly boosted, perhaps on some genres, I can feel there's mild elevation as noted earlier. What is important to me, instruments and percussions sounded believable. The sequence of attack and decays are timed correctly, the tone organic and wholesome. There's ample air and sparkle in upper Mids, lower Mids being rich and naturally dense. I think reflecting on the overall theme of MD4 Mids, I would say it offers just about right - the placement, tonality, transient interchanges and timbral balance. Tried as I might, perhaps I can say only very few IEMs that can outshine MD4 on this element - and these IEMs are the likes of Shure KSE1500 and ER4SR that I am referring to. Otherwise if not comparing side by side, MD4 assuredly offers great Mids for my taste and preferences. And yes, vocals wise, again the same can be said for MD4. Both Male and Female vocals appeared natural as how they are meant to sound like. The contralto of Diana Krall & Sinne Eeg, the Soprano of Alison Krauss, the Baritone of Nick Cave - all sounded realistically natural to my ears.



Now, this depends on which Switch being selected. What I am describing here reflects the usage of MD4 on "Treble" set. Over the years, I would have describe myself as more prone to being favoring "brighter" neutral sort of sound that I get from the Etys. With this perspective, MD4 offers the sort of Treble presentation that I like - it has good sparkle, air and shimmer with the right amount of vibrancy. There's great details to be had, I can hear subtle upper frequency nuances especially for tracks that offer lots of splashy percussions and airy stringed instruments. Take Kitaro for example, Matsuri being his all time top recordings. I was actually mesmerized by how properly sparkly and lively the percussions are, yet there's good smoothness to retain realistic decays on the splashy edges. The best part, treble also sounded crisp and smooth at the same time, not an easy feat to achieve. It never gets fuzzy or overly edgy.



MD4 offers some of the best Bass I have heard within this price point. I would even say it is on par with what I heard from the likes of SeeAudio Yume Midnight (which is a neutral Harman Curved unit). For one, Mid-Bass offers rich yet well controlled body mass and density. Perhaps a bit subdued for most Bassheads, but for me the amount and vibrancy is just about right. It has speed, texture and ample punch to keep things exciting and polished. Perhaps most importantly, how versatile it is with different type of Bass. With stringed Bass, I can clearly hear convincing vibe of bass notes that is super tidy and crisp. With percussion Bass, the the tempo being realistic and vibrant - yet never overbearing. With Electronic Bass - now this is where MD4 somehow manage to transform itself into a Basshead sort of device haha. Hans Zimmer's Mombasa and KRAFTWERK's "Radioaktivität (2009 Remaster)" jumped at me with groovy and thumping Bass performances - the sort of sound that makes the head bobbing to the tunes.
The chemistry between Mid-Bass and Sub-Bass is well orchestrated to say the least. Both respecting each other spaces. Mid-Bass never attempting to overshadow the lower segment - also respecting the territory of lower Mids, always well behaved and tight. Sub-Bass itself being subtly rich and dense, offering deep enough extensions with believable decays



Technically, MD4 offers great prowess especially with layers separation, details retrieval, spatial imaging, holographic positioning and depth of soundstage. MD4 offers big sound, period.
If I am to nitpick, perhaps I wished that soundstage width could be a bit wider. Not that it is narrow, in fact it is quite on par with many others that I have ever used. But because the sound presentation itself is rather large, a wider soundstage could have made it perfect. Nonetheless, I am still satisfied with the depth and breadth of sound to allow even the most complex of composition with their own spaces without intermingling with each other cramped.
Being strong with imaging and spatial positioning, I have found that MD4 will serve amazingly great as well for FPS and TPP gaming, where environmental sound will prove critical for immersive experience. Footsteps and shots directions being succinctly clear and precise.
Additionally, MD4 has the speed and resolution no matter what I threw at it. Be it 200 BPM Black Metal or highly complex Sinne Eeg Jazz composition, MD4 exhibited great agility to handle those demanding output thus avoiding any muck up or congestion.



Now this is interesting. Officially MD4 is the lowest impedance IEM I have ever had. I was initially quite skeptical with that low 8 Ohm resistance.....with the majority of my sources being at least 2 to 4 Vrms. And true indeed, MD4 exhibited audible floor noises when paired with VE MEGATRON and Ovidius B1 - however, the floor noises aside (only on silent passages), MD4 also exhibited amazing scalability with all the power pumped in. For my own usage, I have found that MD4 sounds the absolute best when paired with CEntrance DACport HD and Cayin RU6 - we are talking about some serious near TOTL like synergy here. Despite being lowly with impedance (and high on sensitivity), MD4 never ended up being shouty or edgy.
I must say though, MD4 will already sound amazing with lower powered sources as well. With Abigail and Avani, both 1 Vrms rated I can totally be satisfied and would probably not miss my No.1 DAC/Amp of DACport HD.
So I must say that this amazing versatility of MD4 is one hell of value to be appreciated with.


Final Thoughts ❤
Alright, there it is. To summarize I will not hesitate to say that Hidizs MD4 comes highly recommended - especially for those looking for great balance between fun and polished IEM performances. Hard as I tried, I have not been able to find any glaring flaws worth complaining about - except that I wished the Soundstage could be wider....or Hidizs making Foam tips included in the package. Sound wise, subjectively for my taste and preferences, I find MD4 to be a wholesome and very satisfying unit. It has great organic balance devoid of any metallic or dry deposition that can be found in many other offerings (especially for BA IEMs), not forgetting how equally great MD4 are with technicalities.
Let's also not forget, MD4 offered very usable tuning options, that alone being totally worthwhile for the price asked.

In my book, Hidizs MD4 is a legitimate winner.


Cheers :D
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As always, well written, and just the right length of a review. Not too long not too short. We will be having this in a tour, and your review makes me excited to listen to it. Thanks for sharing your thoughts mate. 😎
Nice review. I am also enjoying the MD4 with the "Treble" setting, I tried the others and this is so much clearer and better balanced with a superior soundstage. I did find a big improvement with a change of cable, I tried the KBEAR Limpid Pro and the TRI Through which I am now using, there is just a tad more bass without colouring the mids. The stock cable makes the MD4 sound a bit thin. Really good synergy with the Hidizs AP80 Pro X DAP.
I think your cons are a little off track. Otherwise a good review. :L3000:

Cons: -
- The shell may be larger in size for some ears
- Does not include stock foam tips (just silicones)
- Soundstage width not as wide as top tiered IEMs

The shells will always be larger regardless of the size of your ears. They may however be too large to fit smaller ears.
The absence of foam tips being a con is subjective.
You are effectively criticizing their soundstage, for not being as good as a better IEM?

(I admit to being a little OCD)