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Inearz Zen 4 Review – Spectre

Pros –

Very low-profile and comfortable design, ADEL, Nicely extended bass, coherent and organic midrange, Spacious soundstage

Cons –

Laid-back and full vocals can lack openness, Darker treble won’t suit all

Verdict –

If you’re looking for an earphone with class-leading comfort and a sound that won’t fatigue for hours on end, the Zen 4 is a good contender.

Introduction –

Inearz is a CIEM manufacturer from Florida, USA. The company is a main player in the professional audio scene, with various offerings for stage monitoring and audio engineers. The Zen models are their universal line-up targeted more towards enthusiasts. At present, they offer two models, the 2-BA Zen 2 and 4-BA Zen 4. The Zen 2 carries a more balanced sound while the Zen 4 assumes a warmer, smoother character. Both are 3D printed with a super sleek design and offer ADEL modules to maximise wearing comfort.

The Zen 4 comes in at a $599 USD RRP. You can read more about the Zen models and buy one for yourself here.

Disclaimer –

I would like to thank Kaysen from Inearz very much for his quick communication and for providing me with the Zen 4 for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.

Specifications –

  • Drivers: Quad-Synced Premium BA in 4-way crossover (2x Low, 1x Mid, 1x High)
  • Frequency Range: 20 Hz – 20 kHz
  • Impedance: 28 ohms @ 1kHz
  • Sensitivity: 113 dB SPL @ 1kHz
  • 3D printed hypoallergenic acrylic shell

The Pitch –


This is an interesting technology that we’ve seen pop up on several models not exclusive to Inearz. It consists of a membrane with external pneumatic vent that reduces pressure exerted on the eardrum and permits greater loudness perception – hence, Ambrose Diaphonic Ear Lens. Accordingly, the module promises greater wearing comfort and the ability to listen at lower volumes without affecting the volume perceived by the listener. The ADEL module promises decreased pressure on the eardrum has been marketed to listeners with tinnitus due to its safety function. This also opens up the avenue to swap ADEL modules, which can offer varying sound signatures and levels of openness. You can see Stephen Ambrose’s explanation video here.

Unboxing –

The Zen 4 provides a pleasing unboxing experience. Unlike their high-end custom designs, the packaging is more commercial with an outer card sleeve with Velcro lid that showcase the features and specifications of the earphones. Inside is a magnetic hard box with the Zen 4 nestled in a protective foam inlet. Just below is the round zipper carrying case and, inside, a metal hard case with protective foam interior alongside stickers and papers. They aren’t the most compact cases but very protective and of quality design. There’s also a handy 3D printed ear tip holder with cleaning tool, 3 pairs of foam tips and 2 pairs of the remaining size of silicone tips, medium being pre-installed. Handily, the silicone tips have colour coded stems that denote orientation, a nice touch.

Design –

The Zen 4 is a very sleek earphone, nothing special in terms of material choice, but a well-executed acrylic design. As they utilise a 3D printing process, Inearz are able to offer a seamless unibody construction with an even, flawless gloss coating. Silver logos add dimension while etched 4’s on the inner face differentiate the two Zen models that utilise the same base design. They are extremely lightweight and super slim but with a super smooth teardrop design that means no sharp edges to wear on the ear. The ADEL modules are placed opposite the sound tube and are easily removed and replaced should the user want to adjust the sound and isolation.

Though the T2 connector is a selling point of Inearz’ product line, the Zen universals implement a more traditional 0.78mm 2-pin connector likely for more cost-effective replacement. The cable itself is the usual plastics cable that you would see on the vasty majority of CIEMs. It is soft and smooth albeit thin with basic moulded plastic terminations. The plug is low-profile and thin enough to fit into most cases, it also has ample strain relief. Meanwhile, the memory wire ear-guides hold their position well and contribute to a very stable fit especially in conjunction with the lightweight design.

Fit & Isolation –

This is surely a prime strength of the Zen 4, being incredibly compact, especially considering the 4-driver setup inside. They are especially slim with a well-angled nozzle that permits a relatively deep fit as well. In turn, they offer a very low-profile fit that doesn’t protrude at all from the ear. This makes them suitable for sleeping with and also aids wind noise to some degree in lieu of the vented ADEL modules that can be more prone to this when out and about. Otherwise, their compact, rounded design forms no hotspots over time making them perfectly comfortable.

The Zen4 isn’t fully-sealed but offers a good seal, nonetheless, with its deeper fit and compact design. In turn, they are very stable, suitable for performers and workouts where the ADEL modules do a great job at mitigating bone conduction noise. I enjoyed jogging with the Zen 4’s since they drastically reduced the thump from each foot step. In turn, isolation is not as good as a sealed model, but surely still a bit better than most vented designs. They are perfectly suitable for commute but may struggle in especially loud environments such as the metro and air travel.

Next Page: Sound, Comparisons & Verdict

2 thoughts on “Inearz Zen 4 Review – Spectre Leave a comment

  1. I have tinnitus and get easily ear-fatigued. How would you compare Zen 2/4 with an open-back headphone like Sennheiser 6XX for long listening sessions ? I ask because I would pick a headphone over IEM any day, if it weren’t for what ADEL modules promise to offer (hearing protection).


    • Hey there,

      I am not a hearing-health professional so please take my advice with a grain of salt. The general consensus is that over-ear headphones are better for ear health than in-ears as the seal is not as strong and there is reduced pressure on the middle-ear. However, the added isolation of in-ears means that you can listen at lower volumes in louder environments which can offset the advantage – for quiet environments, over-ears would be my pick from what I’ve seen. So the ADEL technology is solving a problem here that is more intrinsic to the in-ear form factor than audio devices in general, so I would not personally say that this contributes to safer listening over an over-ear headphone. Your best course of action is to decide on the most comfortable form factor and listen at a responsible volume, that may be lower than you’d prefer if you listen for long stretches each day. If you are using the headphones for travel or commute, than an isolating in-ear or active noise cancelling over-ear model will be a good investment for you.



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