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Yuin OK1

Yuin OK1 Review

Yuin OK1
Reviewed May 2010

Details: Yuin’s top of the line IEM/earbud hybrid
MSRP: $229 (manufacturer’s page)
Current Price: $229 from
Specs: Driver: Dynamic | Imp: 150 Ω | Sens: 109 dB | Freq: 20-24k Hz | Cable: 4.5’ I-plug
Nozzle Size:5.5mm | Preferred tips: Large single-flanges
Wear Style: Straight down

Accessories (3.5/5) – In-ear nozzle inserts (3 lengths), Silicone single-flange (3 sizes) and bi-flange (2 sizes) tips, rubber earbud covers, and 6.3mm adapter
Build Quality (3/5) – Like all of Yuin’s earbuds, the OK1 uses plastic housings and a thin, rubberized cable terminated with a straight plug. Unlike the PK line, the grilles of the OK1 are actually metal and the screw-on IEM nozzles glide smoothly into place. Like most earbuds, the plastic stems take the place of proper strain reliefs
Isolation (1/5) – The OK1 are basically conventional earbuds with nozzles tacked on. They are open-back and isolate accordingly
Microphonics (5/5) – Like conventional earbuds, the OK1 do not suffer from microphonics the way IEMs do – the ear coupling is too shallow and loose for solid conductance
Comfort (2.5/5) – Since this is an IEM review, I am only evaluating the OK1s when used as IEMs. When worn as conventional earbuds, they are as comfortable as any stock buds. With the IEM extenders, however, the OK1 become a complete disaster. The shape of the human ear is such that the ear canals are not perpendicular to the ear itself, which is why angled-nozzle designs like the Klipsch S4 work so well. Sticking a forward-facing nozzle in the center of a conventional earbud, however, results in an IEM with a gigantic driver bulge and very long stems. Finding a comfortable fit takes a lot of experimentation and deep insertion is nearly impossible. For me the longest nozzles in combination with the largest single-flange tips provided a relatively comfortable (read: 2-3 hours at most) shallow seal. Others may not be so lucky

Sound (8.9/10) – Again, since this is an IEM review, I will not be evaluating the OK1 as a conventional earbud. I simply don’t have extensive experience with other conventional buds, nor do I like the form factor. As an IEM, though, the OK1 clearly holds its own against the best of the best, though proper insertion is perhaps more crucial with the Yuins than most traditional IEMs.

From the bottom up, the OK1 is a bit different from my other IEMs both in signature and presentation. The sound it produces manages to be bright and a bit aggressive, but at the same time extremely refined and surprisingly delicate. Even with ample driving power the bass of the OK1 will probably be its weakest point for the average listener. Bass is similar, both in quantity and impact, to the Head-Direct RE0 – tight, accurate, quite fast, but lacking the rumble and texture that many bass-heavy dynamics provide. However, due to the wider and more open presentation of the OK1, instruments that rely on low notes actually sound more natural than with the RE0. Above 40Hz or so the bass is quite linear, transitioning smoothly into the midrange. The mids of the OK1 are its strongest quality – clear as a bell, detailed, and transparent, they put most traditional IEMs to shame. The midrange actually reminds me of the ATH-CK100 in clarity and transparency. However, the forwardness of the CK100 makes them sound slightly colored in comparison to the OK1. In addition, the OK1 isn’t nearly as touchy with regards to source – the midrange is always neutral and natural. An amazing property of the OK1 is the absolute lack of barrier between the listener and the vocalist, especially when it comes to female vocals, though this comes at a price – a slight loss in texture. Still, the OK1 makes sets like the Klipsch Custom 3 sound veiled. Like the CK100, the OK1 picks up emphasis towards the upper midrange and keeps going right up into the lower treble, resulting in a rather bright and crisp sound shimmering with energy. As a result they are less forgiving of harsh and sibilant tracks than the CK100. Top-end extension is good – better than with the Custom 3/Ortofon e-Q7 and company.

The presentation of the OK1 is again very different from most other IEMs I’ve tried. The OK1 has perhaps the most natural way of separating out instruments and positioning them in the soundstage – the instruments are very evenly spaced in the depth of the sonic stage. Despite not having the absolute widest soundstage around, the Yuins are quite adept at conveying both distance and intimacy, though they don’t fare too well at either extreme. Openness of sound is quite surprising as well – for an IEM the OK1 is downright airy. The resulting sound makes it quite easy to pick out and focus on individual instruments and/or vocalists. Best of all, the OK1 still sounds very coherent and musical, never sounding thin even with the widest and most spacious pieces

Amping: My Sansa Fuze barely reaches listening volume and sounds somewhat anemic with the Yuins and an iRiver T5 actually starts clipping at high volumes. An amp is therefore recommended if using these with an average DAP. Exceedingly powerful players such as my S:Flo2 can drive the Yuins fine without making them sound constrained, but the S:Flo is more of an exception than the rule.

Value (6.5/10) – If I were evaluating the Yuin OK1 on sound alone, the $230 price tag would not be difficult to justify – the incredibly airy and delicate sound of the Yuins is sure to find many fans among those who prefer a more realistic listening experience. As a total package, however, the OK1 lacks the advantages so many higher-end IEMs provide. Isolation and long-term comfort are not in the OK1’s playbook and the build quality is slightly disappointing for a high-end product. On the upside, cable noise never rears its ugly head and it is very unlikely that the OK1 will ever be stolen. In fact, their dimestore-earbud appearance may be a thief deterrent over stock apple earbuds. As usual, the true value of the OK1 comes down to personal preferences in the end. One thing is for sure – for some listeners the sound produced by the OK1 will be able to negate their shortfalls.

Pros: No microphonics, extremely airy sound, great balance, detail, and transparency
Cons: uncomfortable when used as IEMs, almost no isolation





Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


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