IKKO Audio Gems OH1S
Copyright IKKO Audio 2021

IKKO Audio Gems OH1S Review

IKKO Audio Gems OH1S is a hybrid universal IEM featuring a 10mm dynamic driver and a Knowles 33518 balanced armature. It is priced at $199.

Disclaimer: The IKKO Gems OH1s sent to us is a sample in exchange for our honest opinion. We thank the team at ikko Audio for giving us this opportunity.

To read more about IKKO products we have previously reviewed on Headfonics click here.

Note, this 2-page review follows our new scoring guidelines for 2020 which you can read up on here.

IKKO Audio Gems OH1S
IKKO Audio Gems OH1S
The IKKO Audio Gems OH1S is a good pick for people looking for clarity and good treble extensions. The IKKO Gems’ wide soundstage alone blows away the competition in the sub $150 price range.
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$129 Discounted ($199 SRP)

With IKKO’s philosophy of complementing modern ergonomic design with excellent tuning techniques, they have released their new flagship IEM, the IKKO Gems OH1s. A successor of the praised IKKO OH10 Obsidian, the IKKO OH1s Gems is a similar offering priced at $199.

IKKO has equipped their new flagship with an entirely redesigned shell, featuring a mixed-material construction. Aside from the looks, the package gets an improved stock cable, a new dynamic driver, and the inclusion of some newly designed tips.

The IKKO OH1s Gems is currently on sale with a 30% discount, priced as low as $129. The sale is only until the end of the month so do check them out for this sweet deal.

IKKO Audio Gems OH1S
Copyright IKKO Audio 2021

Tech Highlights

On paper, the IKKO Gems OH1S has a similar configuration to previous IKKO IEMs. That means a hybrid universal composed of 1 dynamic driver and 1 balanced armature driver. It uses a similar Knowles BA and a new 10mm deposited carbon nano dynamic coil drive which is tuned to balance the lows, mids, and highs.

What’s unique with IKKO Gems OH1S is its SVAS (Separating Vector Acoustic System) Acoustic Cavity Technology which makes the sound reflection and diffusion angles optimal in a small form factor. It is made from both resin and aviation-grade aluminum alloy to achieve a physical frequency division effect.

The SVAS is said to help in physical tuning, including sound dampening and minimizing mutual interference between the drivers, making the sound clean and transparent. 

The resin cavity that has a sound diffusion structure is located between the 10mm deposited carbon nano dynamic coil driver and the Knowles BA driver while the aluminum alloy cavity is on the shell of the IEM.

IKKO Audio Gems OH1S


The eye-catching play on textures on the external of the Gems OH1S is a feature unique to this monitor. The front faceplate has a matte grey-black color with a textured design resembling gem ridges while the side is accented by a purple glossy resin with a marble-like design.

The back is a smooth matte grey-black color shaped like a slanted triangular pyramid and at the tip is the nozzle there is an oval sound outlet with replaceable filters. The unique oval nozzle is an ergonomic design that follows the natural shape of the ear canal which improves comfort while wearing the Gems OH1S for long periods.

IKKO Audio Gems OH1S

Stock Cable

Unlike IKKO’s previous IEMs with a 0.78mm 2-pin configuration, the IKKO Gems OH1S’ stock cable is a detachable MMCX cable terminated with a 3.5mm gold plated jack.  

Internally, it is composed of a high-purity single crystal copper silver-plated magnetic cable, enabling a more transparent high-frequency sound transmission. Externally, the cable is a blue-red-copper colored wire with a grey tint wrapped design reducing the problems of cable winding.

The cables are thin and light enough to not cause microphonics. It is also comfortable around the ear giving an illusion as if it’s not there. A chin slider is also found to make the cable extra secure when moving around.

IKKO Audio Gems OH1S

Comfort & Isolation

With its small form factor and light cable, IKKO Gems OH1S is extremely comfortable to wear. Even in long periods, there was no pressure inside the ear and no discomfort was found around the outside of the ear.

Isolation of the Gems OH1S is average compared to other universal IEMs. Playing music at comfortable levels drowns out the low hums of the air conditioner that are otherwise heard through the IEMs.


Tips are unique in the Gems OH1S as it features a novel oval-shaped nozzle. IKKO is generous to give 2 pairs of each size (S, M, L) of silicone tips and 1 pair of each size of IKKO’s I-Planet foam tips making it a total of 18 tips.

The silicon tips have an oval-shaped exterior, complimenting the Gems OH1S’ oval nozzle while the foam tips have a circular exterior. Initially, it was intriguing how a round-shaped tip would fit in the oval nozzle, but the round foam tips took the shape of the nozzle as it was attached. Similar tips such as the Spinfits also fit snuggly in the oval nozzle.

Among the 2 tips, I found the foam tips to be more comfortable. The foam tips have a laminated layer which adds to its durability. The foam’s ability to expand and compress also gave a better seal and fit.  

The sound did change with the tips. The foam tips gave more tamed highs and slightly more sub-bass than the oval silicone tips.

IKKO Audio Gems OH1S

Packaging & Accessories

True to its branding, the IKKO Gems OH1S includes IKKO unique packaging and accessories seen in the Obsidian and OH1 such as the external sleeve with an Anime character, IKKO leather pouch, and of course, the IKKO badge pin.  

The package is securely enclosed in a black hard box with a magnetic flap with the Gems OH1S  found inside the flap, displayed with a caricature of an overview of the package and the IKKO badge. Beneath is a black envelope containing the manual and warranty card, stock tips, extra nozzle filter, leather case, and cable.

The IEM pouch is a familiar leather soft pouch in a light brown color with a minimal embossed IKKO logo with a strap to secure it. Although it does not protect the IEM from external pressures, it’s a nice inclusion that is unique and elevates the overall look when carrying it around. Inside is a plain pocket with no partitions, just enough to carry the Gems and cable.

Sound Impressions

Tested with an iBasso DX150 and AMP6.


The bass tuning of the Gems OH1S’ lows is rolled off. A deep rumble in the sub-bass is missed when listening to bass-heavy music. Nevertheless, it’s still felt, although faint. Drum hits are also a bit hollow, making drum hits sound faint and dull in certain tracks.

Good control with fast attack and delay in the mid-bass does however make up for the lack of sub-bass. It’s detailed, making note distinction to fast bass tracks noticeable.

Despite the lack of bass of the Gems OH1S, it is not muddy and it does not bleed higher frequencies, making the overall sound presentation clean and transparent, complementing the overall tuning of the IEM. 


One thing notable is that the crossover between timbre from dynamic and BA drivers was not noticeable. The BA driver was tuned properly to accompany the overall presentation of the dynamic drivers.

Along with the pleasant forward midrange tuning, the Gems OH1S have a balanced midrange region. The lower and higher midrange felt equal, such that male and female vocals are on the same positioning. Electric and acoustic guitars also sound natural and crisp.

Given the two-driver configuration of the Gems OH1S, the midrange is overall impressive. However, the timbre presentation is a bit dry and thin, which I presume to be caused by the lack of separately tuned drivers.


The strength of the IKKO Gems OH1S definitely lies in the treble region. It has a pleasant tuning with good treble extension with good presence and clarity. The cymbals also do make a prominent impression but it is a little splashy despite joining multiple instruments. Tracks are airy with a sense of brilliance, giving a fresh and crisp presentation.

There was no notable harshness in the highs, however, although the Gems OH1S tends to be bright-sounding overall. There is some amount of sibilance, it is hardly noticeable through different tracks.

Soundstage (including imaging)

Staging on the Gems OH1S is surprisingly above average. It has more depth and width seen in similarly priced IEMs. It does not feel cramped, it’s in fact, spacious in its own right. All things considered, the soundstage is impressive enough for an IEM at this price point.

Imaging is also generally good. Instruments and vocals are distinct and do not feel unidirectional. Sound layers are emphasized by tracks with backup vocals in the background wherein sound is projected in a 3-dimensional space, which is actually impressive for a hybrid universal.

IKKO Audio Gems OH1S



With a rated impedance of 32Ω and 109dB sensitivity, the IKKO Gems OH1S is not that difficult to drive. Both iPhone 12 Pro Max and iBasso DX150 can power it with no sweat. Soundstage and imaging do, however, scale with the dedicated audio player Ibasso DX150. There was also no unwanted noise observed on both sources.


With the Gems OH1S leaning on a bright tuning with recessed lows, it would be best to pair it with a warm, balance, or dark source, depending on personal tuning preference. For people sensitive to treble upticks, it would be best to pair the Gems with a dark source to balance the bright tuning.

The Ibasso DX150 (AMP6) is known to have a natural sound signature with a warm tonality. Paired with the Gems, treble has a good extension, however, the lows are still lean for my taste.

Nevertheless, pairing the Ibasso DX150 with the Gems OH1S still produced a good overall synergy. Overall tonality is pleasing with a clear and transparent presentation, which makes it easy to enjoy listening to minute details.

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