Hidizs Mermaid MM2 IEM Review






Hidizs Mermaid MM2 IEM Review  



Hidizs Technology Co. Ltd. was founded in 2009 and offers a wide variety of portable audiophile equipment’s such like Digital Audio Players (DAP), Digital to Analogue Converters (DAC), DAC/AMP Dongles and In-Ear Monitors.

The Mermaid MM2 is a Hybrid IEM that comes with an uncommon driver configuration, which is a combination of 1x 6mm dia. Low Voltage Magneto-Static BM (Balanced Membrane) + 1x 10.5mm dia. Dynamic Driver with a PEK Macromolecule Polymer Diaphragm. This driver combination is located inside an Eco-friendly Resin Body that features a Lozenge-Cut Faceplate. The MS2 offers also 3x Sound Tuning Valves and a detachable cable with 4core Hybrid Wires (2×High Purity Silver Wires & 2×OFC Wires).





I would like to thank Hidizs for providing me the Mermaid MM2 IEM as review sample. I am not affiliated with Hidizs beyond this review and these words reflect my true, unaltered, opinions about the product.




Price & Availability:

The Hidizs MM2 is an In-Ear Monitor that is priced under the 100 US$ price level and is actually available for 79,00 US$. More information can be found under the link below;





Package and Accessories:

The Hidizs MM2 comes inside a black plastic box with a top cover that is wrapped with a cardboard that that sports the Hidizs brand logo and the illustration of the product.


The box of the comes with the following contents;

  • 1 x pair of Hidizs Mermaid MM2 In-Ear Monitor
  • 1 x 4 Core Hybrid Wire Cable with 2-Pin Connectors
  • 6 x pairs of silicone ear tips
  • 1 x Protective Leather Case
  • 3 x pairs of Sound Tuning Valves (2 pairs are located on a metal plate)
  • 1 x Print Material


The MM2 comes with a fairly rich set of accessories, including 3 pairs of silicone ear tips with wide opening and 3 pairs of silicone ear tips with long nozzle and small opening.

The stylish leather case is of high quality and has a colour combination of black and brown with the Hidizs brand logo on the front.

Inside the box is also a metal plate with two pairs of sound tuning valves, which looks very stylish.



Design, Build Quality and Fit:

The Hidizs MM2 features a very comfortable and lightweight monitor shell that is made from ECO Friendly resin material. The monitors are available in two colour option, which are the one with semi-transparent black shell+black faceplate and the one with a transparent shell+silver faceplate like my review unit.

On the front to the monitors is a very stylish looking faceplate with a so called Lozenge-Cut Faceplate design.

Here is also one of the 3 available sound Tuning Valves that you can screw and unscrew to change the sound character of your Mermaid MM2.

The rear main body features the sound nozzle, the 2-Pin female connector and the left right indicators. The sound nozzle is made from metal that sports a mesh on the top to avoid the insertion of unwanted particles like dust, ear wax, etc.

On the top of the rear part is the 0.78mm diameter 2-Pin female connector which has a small elevation. At the rear side of the monitor shell is the web link of the company that is printed on the surface.




Detachable Cable:

The Hidizs MM2 comes with a 4 Core Hybrid wire cable, which has a combination of 2x High Purity Silver wires & 2x OFC wires.

The cable has a transparent insulation made of soft plastic material.

The cable features 0.78mm diameter 2Pin male connectors that do fit pretty tight to the female connectors that are located on the top of the monitor shell. Each connector features a transparent plastic housing and each side has a left & right indicators. The indicators are not very visible which is my only complain about the cable.

Near the connectors is a transparent ear guide that will offer higher comfort on the go.

The Y-splitter is made of metal that has a textured surface in rose gold and silver colour. The y-splitter also made of metal material in rose gold colour.

The 3.5mm TRS headphone jack has a strait profiled metal housing in the same colour combination of silver and rose gold. The housing sports the Hidizs branding and a transparent plastic strain relief for extra protection.

The overall build quality of both the cable and the monitor shells is pretty good for a product at this price range.




Fit & Isolation:

The monitor shape of the Hidizs MM2 pretty comfortable and didn’t hurt my ear concha even after longer listening periods. The isolation on the other hand is on an average level which is sufficient for moderate noisy environments like the bus, metro or train.


Paring & Drivability:

The Hidizs MM2 is an easy to drive In-Ear Monitor thanks to a pretty low impedance of 18Ω and sensitivity around 104dB, which makes it very compatible with relative weak sources like a Smartphone or Tablet.







Technical Specifications:

  • Driver Configuration   : Hybrid Driver Configuration 1x MS BM + 1x DD
  • Magneto-Static Type  : 6mm dia. Low Voltage Magneto-Static Balanced Membrane Driver
  • Dynamic Driver Type : 10.5mm dia. DD with a PEK Macromolecule Polymer Diaphragm
  • Frequency Response : 20Hz-40kHz
  • Sensitivity                   : 104dB±1dB@1kHz
  • Impedance                  : 18Ω@1kHz
  • Rated Power              : 5mW
  • Cable Material            : Hybrid 4Core Wires Cable (2×High Purity Silver & 2×OFC Wires)
  • Cable Length              : 1.2m
  • Plug                            : 3.5mm




Equipment’s used for this review: 

  • IEM’s              : Hidizs MM2, IKKO OH2
  • DAP/DAC       : Hidizs AP80 Copper, iFi Audio xDSD Gryphon




Albums & tracks used for this review: 

  • Adele – My Little Love (Spotify)
  • Hayley Westenra – Odyssey Album (Dezzer HiFi)
  • Sarah McLachlan – Angel (Flac 24bit/48kHz)
  • Sertap Erener – Aşk (Flac 16bit/44.1kHz)
  • Edith Piaf – Non Je Ne Regrette Rien (Flac 16bit/44.1kHz)
  • Diana Krall – So Wonderful (DSF)
  • Aretha Franklin – I Say A Little Payer (Flac 24bit/96kHz)
  • David Bowie – Heroes (Flac 24bit/192kHz)
  • Elton John – Rocket Man ((Flac 24bit/96kHz)
  • Isaac Hayes – Walk On By (Flac 16bit/44.1kHz)
  • Sting – Englishman in New York – (Flac 24bit/48kHz)
  • Dave Gahan – Kingdom (Tidal Hi-Fi)
  • U2 – Sunday Bloody Sunday (Flac 16bit/44.1kHz)
  • Armin Van Buuren – Vini Vici (Flac 16bit/44.1kHz)
  • Massive Attack – Angel (Flac 24bit/192kHz)
  • Lorde – Royal (Flac 24bit/48kHz)
  • Gogo Penguin – Raven (Flac 24bit/192kHz)
  • Portishead – It Could Be Sweet (Spotify)
  • Charly Antolini – Duwadjuwandadu (Flac 24bit/192kHz)
  • Michael Jackson – Billie Jean (Flac 24bit/192kHz)
  • Ferit Odman – Look, Stop & Listen (Flac 24bit/192kHz)
  • Chopin – Nocturn No. 20 In C-Sharp Minor (Flac 16bit/44.1kHz)
  • Fazıl Say – Nazım Oratoryosu (Live) (Flac 16bit/44.1kHz)
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Deezer HiFi)
  • Otto Liebert& Luna Negra – The River (Flac 24bit/192kHz)
  • Lunatic Soul – The Passage (Flac 16bit/44.1kHz)
  • Photek – The Hiden Camera (Spotify)
  • Muse – Hysteria (Flac 24bit/48kHz)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Opeth – Windowpane (Flac 16bit/44.1kHz)
  • Megadeth – Sweating Bullets (Tidal Hi-Fi)
  • Rush – YYZ (Flac 16bit/44.1kHz)
  • Slayer – Angel of Death (Spotify)s
  • Liquid Tension Experiment 2 – Acid Rain (Spotify)
  • Yosi Horikawa – Bubbles (Spotify)






About Sound Tuning Valves:

The Hidizs MM2 comes with 3 pairs of Sound Tunings Valves, which are the Bass, Balanced and Treble Valves. Two Treble and the Bass Valves are located on a stylish looking small metal sheet that shows the description of each Tuning Valve. The Balanced Tuning Valve came pre-installed on the top of the Monitors.

Each Sound Tuning Valve has a mesh on the top, while all do have a different color. The mesh of the Bass Valve is in red, the one on the Treble Valve is silver, while the mesh of the Balanced filter is in Rose Gold.


Bass Valve:

The Bass Valve has a slightly warmer tonality of all shells and shows smoother overall presentation. The bass is slightly more highlighted and impactful, while the midrange is reproduced with a smooth yet moderately transparent character. The upper midrange and treble are sounds slightly less pronounced and more relaxed compared to the Balanced and Treble Valves.


Balanced Valve:

The Balanced Valve offers a slightly more balanced tuning with a relative linear and fast bass character, while it is inferior to the Bass Valve in terms of bass depth and emphasis. The midrange is slightly more transparent and airy compared to the Bass Valve. The treble range of the Balanced Valve is more successful in terms of extension, sharpness, control compared to the Bass Valve, but inferior to those of the Treble Valve. This Sound Tuning Valve can be described as the Reference tuning of the MM2.


Treble Valve:

The Treble Valve is the one with the brightest tonality. It shows slightly more treble emphasis compare to the Balanced Valve. The Bass sounds a bit tighter but losses volume compared to the Balanced Valve. The upper midrange and treble region is produced with a higher sense airiness and sparkle, while it sounds a bit less controlled and natural compared to the Bass and Balanced Valves in the upper register.



The Sound:

The Hidizs MM2 is an In-Ear Monitor with a fairly warm tonality. It offers in general a smooth and fatigue free listening experience, while it shows in general a moderate sense of clarity from the lows up to the highs. The bass is impactful and fairly controlled, the midrange on the other hand has a warm tonality and shows a moderate level of transparency, while the treble response is pretty smooth and fatigue free.

This review has been written after a Burn-in period of approx. 50 hours. Please note that my sound experiences below are based on the Balanced Tuning Valve, which is the reference filter of the Hidizs MMS2. I have used the stock cable and silicone ear tips with the wide opening. Sources are the Hidizs AP80 Copper and iFi Audio xDSD Gryphon.


Bass / Midrange / Treble / Soundstage:

The subbass region of the Hidizs MM2 shows a sufficient level of depth extension, while the level of clarity is on a moderate level. It has a warmish tonality and a full bodied yet soft character. It is possible to feel the some good level of rumble in songs like Massive Attack’s “Ange” and in Lorde’s “Royals”.

The midbass region is impactful and fairly controlled, while it can sound a bit muddy in bass heavy track. The impact will satisfy most listeners with exception of hardcore bassheads. The bass shows in general a good level of impact, tightness and speed. Instruments like snare drums and bass guitars do have an average level of extension, while bass guitars do sound a bit soft in tonality.

The Hdizs MM2 comes with a warm midrange tonality that has an average level of transparency and airiness. The lower midrange shows a good grade of depth and moderate sense of clarity. Male vocals do have a warm, romantic and intimate tonality with good level of detail and extension. Instruments such like violas, trumpets or acoustic guitars do sound bassy, smooth and emotional.

The upper midrange mildly highlighted, fairly detailed and smooth in its presentation and shows in general a sufficient level of clarity and extension that does avoid a veiled or dry presentation. Female vocals do sound slightly more detailed compared to male vocals and are reproduced with an efficient level of extension and crispiness without to sound peaky sibilant or harsh.

The Hidizs MM2 has a mildly bright and pretty forgiving treble presentation that is less dominant than upper midrange and lower frequency region. The transitions from the upper midrange to the treble region are in general controlled.

The general brightness level of the treble range is on an average level, extension and resolution do decrease towards the upper register. The Hidizs MM2 is missing some sparkle and airiness. The general treble presentation can be described as fatigue free and ideal for longer listening periods.

The Hidizs MM2 offers a sufficient soundstage performance for an In-Ear Monitor at this price range. The separation and placement of instrument and vocals is fairly accurate. Moreover, the soundstage shows a moderate sense of depth and airiness, while the wideness is on an efficient level.




Hidizs MM2 versus IKKO OH2:

The Hidizs MM2 has in general a warmer tonality compared to IKKO OH2 that sounds more neutral in direct comparison. The MM2 has the upper hand when it comes to the subbass depth and intensity, while the OH2 shows a more neutral tuning in this area. The midbass region of the Hidizs MM2 has the upper hand in terms of impact and extension, while the IKKO OH2 offers a slightly better performance when it comes to clarity and resolution and control.

The Hidizs MM2 has a warmer midrange tonality and fuller presentation in this area, while the IKKO OH2 shows a more neutral tuning with slightly better sense of clarity and resolution Male vocals do sound more musical and emotional when I listen to the MM2, while both IEM’s are successful with female vocals. However, the OH2 sounds slightly more airy and offers also a bit more micro detail in this area.

The treble range of the IKKO OH2 is more highlighted and bright in tonality compared to the Hidizs MM2, which sounds more relaxed and forgiving in this region. The OH2 sounds a bit dry in the upper register, while the MM2 offers a fuller and sweeter tonality.

Both IEM’s do offer a fairly precise separation and placement of instruments and vocals. However, the Hidizs MM2 has the upper hand in terms of soundstage depth, while IKKO OH2 has the slightly edge when it comes to the wideness and airiness of the stage.




Hidizs MM2 is a stylish looking In-Ear Monitor with that offers some new features like the unique Sound Tuning Valve’s and an uncommon Hybrid Driver Configuration, which is a combination of one pretty small Low Voltage Magneto-Static Balanced Membrane Driver + one Dynamic Driver unit. The MM2 offers a smooth and relaxed sound profile from the lows to the highs, which is ideal for longer listening periods.




Pros & Cons: 

  • + Smooth & Relaxed Sound Profile
  • + Stylish Faceplate Design
  • + Unique Driver Configuration
  • + Rich Set of Accessories


  • – Limited Technicality
  • – Relaxed Sound Profile may not for everyone
  • – Average Midrange Clarity


Thank you for the Read!




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