Yuin OK2 review and comparisons to PK2, CM700, PK1 and OK1

[kostalex]

Review notes

Upside-down review: I start from pics and conclusions, followed by all the details.

Comparison-based review: Rather than describing Yuin OK2 standalone, I compare it to other earbuds, mostly to Yuin PK2. Also I mention Yuin OK1, Yuin PK1 and Audio-Technica ATH-CM700. These all are world 5 best earbuds.

Pics and build

OK2 is built exactly the same to OK1 as well as PK2 is built exactly the same to PK1. Moreover, OK2/OK1 are built very simillar to PK2/PK1 - simple, black and solid, while have the following differences:

• OK2/OK1 are slightly deeper and have a hole covered with a tiny grill. Screw a tube with an eartip into this hole to convert earbud into canal phone.
• They have a new cord which is covered with something like rubber instead of plastic. I hope, it will keep its flexibility at a cold weather better than PK1/PK2 cord did.

Top left: OK1 with donut foam (left) and with eartip attached (right). Bottom left: PK1. Bottom right: OK2 without foam (left) and with tube attached (right). Top right: different eartips.

Summaries and conclusions

OK2 is top-league earbud and extremely refined successor to PK2. In contrary to OK1/PK1 pair, OK2 keeps the same sound sig as PK2. But overall SQ of OK2 is very much higher than PK2, so Yuin may either retire PK2 or price them differently.

OK1 is an earbud first and foremost. Its "canal phone mode" can not replace the good canal phone or IEM.

How OK2 sound quality compares to other cans

CM700: OK2 is very close to or even on par with CM700. I have to compare them face to face for final conclusion. Anyway, I prefer OK2 since CM700 is too harsh and dry sounding for me. YMMV because earbuds sound depends on the ears and ear canals shapes.

PK1: OK2 yields to PK1 in overall SQ, while may outperform it on some songs if both are unamped.

OK1: No surprises here, OK2 is definitely inferior to OK1. But a very weak source (say Shuffle) may make them level.

Rating to other cans: I divide all the cans I listened into 3 classes - Hi-Fi, Mid-Fi and Low-Fi. I divide each class further with 3 levels. So here are my ratings:

• H1 HD650, W5000, SR-404
• H2 Denon D2000, AKG 701, W1000, ER-4S, E500, E530
• H3 DT880, ER-4P
• M1 DT990, AD1000, K501, Ergo 2, UM2, OK1
• M2 DT770, SR225, HD595, AD900, K271, MDR-F1, E4c, PK1
• M3 AD700, HD555, HD280, DT660, SR80, ER-6i, CM700
• --- OK2 is somehere
• L1 iGrado, A900, HD485, K181, E3c, UE 5 EB
• L2 PortaPro, PX100, DT231, K81, D-Jays
• L3 KSC-75, SportaPro, PXC 250, K27i, UE 3, E2c, CX300, Marshmallow
• --- earbuds borderline --- PK2
• other earbuds here

Yes, I place OK2 somewhere in between Mid-Fi and Low-Fi full size cans.

OK2 sound signature

As I said before, OK2 sound signature is same to ... yeah, PK2. It is hard to describe it exactly, so digg the forum for more descriptions. Anyway, I'll do my best:

OK2 is all-arounder, very even and balanced across the spectrum. The spectrum is recessed on both ends, there are no deep bass as well as extended highs. Bass is fast and very detailed, its amount is just right. Mids are just slightly forward, neutral but lack of natural timbres, decay and harmonics when comparing to uber cans. Voices are nicely detailed with no touch of sibilance. Imaging is terrific: instruments has bodies and positions, soundstage is 3D and deep, the whole sound has a great integrity itself as well as a nice joint to surroundings. OK2 combines technical competence with fun and soul, providing you with accurate reproduction of the music itself and the emotions the music carries.


How I scored OK2 to PK2

Comparing two earphones by any parameter, I determine the winner and then evaluate its advantage using the scale from 0 to 3 points:

• 0 - Both cans are equal. They may sound differently, but no one is better.
• 0,5 - The advantage is arguable or negligible.
• 1 - The advantage is obviously here, but it is not valuable for me. I like how the winner sounds, but I also may live happily with competitor. I am not willing to spend time and money upgrading to better one.
• 1,5 - The advantage has some value for me. I am still able to listen to looser, but I am missing for winner. I will upgrade the looser to winner if someone makes a good offer, but I will not pay a lot of efforts to upgrade seeking.
• 2 - Critical advantage which is very important for me. I will do my best to get the best of two. I will avoid listening to looser.
• 3 - The comparison is not fair, the winner and looser are from different leagues.

OK2 to PK2 comparison and CM700, PK1, OK1 appearance

I used iPod Classic, Shuffle and Echo Indigo DJ for sources. Both OK2 and PK2 were used with stock foams without holes. Unfortunately, my PK2 was recabled with iGrado cable. But I did not notice that this recabling affects PK2 sound a lot. Its SQ is at least the same as it was before. So I beleive it is fair comparison. Let's go:

Sensitivity: Roughly the same. Both are sensitive enough to work perfectly even with weak sources, like Shuffle. Both are more sensitive than CM700 and much more sensitive than PK1/OK1. Amping does not provide enough benefits to PK2/OK2 to hassle with those cumbersome DAP/LOD/Amp combos.

Bass depth: +0,5 to PK2. Both roll off completely below 50 Hz and are not strong performers up to 80 Hz. So both are not on par with OK1, PK1, CM700 (listed in order of bass depth) here.

Bass impact: +0,5 to PK2. Both have the same impact as OK1, noticeably less than PK1, obviuosly more than CM700. I consider this bass amount as neutral though I prefer stronger bass. You may get more bass with other cushions, see my recommendation on earbuds cushions.

Bass quality: +2,5 to OK2. No way PK2 is a contender to OK2. OK2 bests even PK1 here (not a lot though, say +1) and yields only to OK1 and CM700 in speed and accuracy of bass.

Mids quality: +2 to OK2. PK2 sounds muddy and overwarmed in comparison, OK2 is certainly more clear and detailed. OK2 is placed between PK2 and CM700 in terms of midrange. Comparing to PK1/OK1, OK2 midrange is quite "schematic", lacking overtones and details while PK1/OK1 mids are "realistic", natural and mature. Comparing to CM700, OK2 also lacks decay and details, while provides more body and warmth to midrange. CM700 mids are dryish on comparison.

Highs quality: Draw. PK2 highs are slightly stronger, OK2 sounds softer. None is smooth or detailed comparing to better earbuds. Even CM700 sounds better here though I consider its highs as aggressive.

Details: +1 to OK2. PK2 has almost the same details but it is very muddy in comparison, thus it is not so easy to detect them. OK2 details are less than those of PK1, CM700, OK1 (listed in order of detailisation), but they are better integrated into the sound in comparison to CM700, which is overdetailed.

Soundstage size: +2. PK2 sounds inside the head, OK2 provides outside-the-head and deeper sound. OK2 sounstage size is same to OK1 and is less than those of PK1 and CM700. OK2 interacts with the real sounds surrounding you the same way OK1 does. It embeds its sound into the real space, mixing a real world with music and creating an illusion of band in your room. I like this way very much.

Instruments separation: +3 to OK2. PK2 is congested, instruments are crowding and floating without exact positions. OK2 combines the analitical presentation of OK1/CM700 with the integrity of PK1. If you listen relaxed then you hear a music in a whole. Try to concentrate just a bit and you easily pick out any instrument and its position. In terms of pure separation OK2 is on par with PK1 and yields slightly to OK1/CM700, but I prefer its overall presentation to any other earbud. OK1/CM700 are too analitical in comparison, PK1 sounds more congested on complex passages, while OK2 has the best of both worlds. Great job, Yuin!

Comfort: +0,5 to PK2. As you can see on the pics, OK2 is a tad bigger (deeper). They do not "disappear" in ears as easily as PK2 does. On the other hand, OK2 fit is more stable in my ears.

Canal phone mode

The idea of convertible earbud is great. I really hoped for OK2 to be an ultimate solution - earbud and canal phone the same time. I hate to say that, but current implementation is useless.

1) It is incomfortable, because the tube with eartip is centered. There was more comfortable Sony EX-90 where ear tips were located at the front edge of the earbuds:


2) There is no isolation. I tried different tips, including biflanges and UE foams. I jammed them into my ears with no luck. The back of OK2 is open, so there is no isolation to talk about.

3) The better seal you reach, the worse sound you get. I reached the best seal with UE foams and pretty good seal with biflanges. Most of the highs died, while the rest sound false. Bass became boomy. CX300 or JVC Marshmallow sound better in comparison.

If you don't seal the ears with OK2s ear tips, then its sound is quite close to earbud mode, just slightly worse. But why to use the tips at all? I have the only so-so answer. You may hook OK2 eartips into your ears to provide more stable fit. It will better keep its position and less likely to fall out if you are jogging, f.e.

More on the subject

Yuin OK1 review

6 more good earbuds: PK1, PK2, CM700...

And recommendation on cushions for all of them

[tstarn06]

On the covertibility front, same with OK3. The sound tube thing is a complete bust, considering how great the OK3s sound without it straight up as ear buds. Nice idea, bad implementation. Not even sure if could ever be done because of ear bud design, in fact.

[smith]

Another great review, well done looks like I will be picking up these and the OK1...

[smith]

Just a quick one, did you use the pads with holes or normal ones. How did this effect the sound. I could not use the hole pads with the pk2's due the high's and lack of bass.

[kostalex]

Both OK2 and PK2 were used with stock foams without holes. I also prefer PK2 with usual foam, which tame highs a bit.

[blehmann]

I am probably missing something, but when will the ok series be released and how will it be priced?

[kostalex]

Sorry, I do not know.

[faichiu]

Can unamped OK2 sound better than amped PK1??????

[kostalex]

No

[faichiu]

er4p is rated Hi-Fi?????

[kostalex]

Originally Posted by faichiu

er4p is rated Hi-Fi?????

Yes, entry level Hi-Fi. Pay attention that Hi-Fi is not a top category. The top is High-End which is not listed because I've not heard any. High-End includes rare cans like R10, Orpheus and so on.

[babi12]

Nice review. Any news when will it come out?
Will OK2 replace PK2 ?

[AudioCats]

hmmm, looks like PK1 performence is somewhere around the SR225 level? Interesting.

[kostalex]

Originally Posted by AudioCats

hmmm, looks like PK1 performence is somewhere around the SR225 level?

Some people rate PK1 even higher See below:

Originally Posted by tygger

... Otherwise I treasure Yuins as a best item in my modest collection, placing them above SR325i...

[nicolas000]

Hello guys !

I wandered how good is the OK2/Ipod classic (no amp (for how long? :-/)) association ?

I did not managed to find any comment on it...

Thanks !!!