antonyfirst
Headphoneus Supremus
This review is my view of the so much talked Yuin earbuds: the PK1, PK2, OK1, OK2 and OK3. I want it to be a guide to give anyone looking for what earphone fits his needs better.
I'll add other AB comparisons I have done with other headphones I have been owning lately.
The earphones: PKs vs OKs
Like previously expressed by Kostalex, the OKs are slightly thicker than the PKs.
The Yuin OK series is much better looking, the earphones have metal parts, look sturdy and precious. I find the PK series a bit more comfortable when comparing them directly to the OKs. Both series are very comfortable as earbuds.
Presentation: PKs vs OKs
The OKs are a more homogeneous line compared to the PKs.
The PK1 and PK2 are very different, with the PK1 being warmer, more thumpy and midbassy than the PK2, and a lot bigger sounding.
The OK earphones share the same sound signature, while adding refinement and sound qualities to each step.
I feel the OKs start sharing a similar sound signature to the PK2, improving it.
PK2 vs OK3
I find these earphones very similar. The most noticeable difference between them is sensitivity. The OK3 are a bit less sensitive than the PK2. Using a MuVo and the OK3 I have to raise the volume of one notch to match the same volume of the PK2. It's a slight difference.
When I approached the PK2, I didn’t know what to expect. After reading Kostalex’ review (many months ago), I expected they sounded very similar to Koss KSC75. Furthermore, when I used to talk to Kramer about the Yuins, one year ago, I was figuring that the PK2 were “grado-like”. At that time, my only experience with a “grado” sound were the d-JAYS, which I profoundly disliked as innatural, due to the extremely nasal midrange and distorting electric guitars.
The PK2 are a lot more natural than d-JAYS (in the end I discovered that d-JAYS aren't gradoish, but this is another story). The PK2 are similar in sound signature to the Koss KSC75, but with narrower soundstage and cleaner sound, especially in the bass and midrange, where the KSC75 sounded muffled and dirty.
The PK2 are also more natural than the Grado SR-60, but the latter is bigger sounding and shows better instrument separation.
OK2 vs PK2 vs ER4P
The OK2 share the same sound signature as the PK2. Neither is bass heavy, but not as bass light as the ER4P (which used for constant AB with the OK2). Bass is not as deep as the ER4P, thus the OK2 might lack some impact compared to the Etys. The only open earbud design to have some deep bass in this review is the PK1, while other lose at bass extention.
Midrange is similar in both PK2 and OK2. The lower treble is slightly forward, which gives some sibilance with sharp vocalists like Freddy Mercury, but nothing dramatic, not as with the stock Super.fi 5 Pro and their treble spike, or the Etys and their “saw” frequency response.
Compared to the ER4P, the OK2 are free from the great sense of glare and “special effects” that Etys have. Stock ER4P are artificial, giving a fake sound signature and some sickening sense to the music.
The OK2 are slightly warmer than the ER4P and don't sound empty, like Etys do. The OK2 are quite detailed, but less and differently from Etys, that present details not meant to stand out.
I tend to like the OK2 and ER4P on the same level. The OK2 are more natural, the ER4 are more analytical and deeper. The OK2 have wider soundstage and more natural sound. The Etys would be superior if it wasn't for certain flaws that make them super-sharp.
More about the OK2 vs PK2:
Treble is similar in quantity on both OK2 and PK2, but more extended with the OK2. Both have less treble quantity than Etymotic ER4P.
The OK2 seem to me also more extended in bass than the PK2, giving better sense of rhytm.
The biggest differences between the two, anyway, come out when comparing the soundstage. The OK2 are widely out of the head, in the same league as the PK1 and the OK1. The PK2 (as well as the OK3) are in the head and don’t give the same feeling of using a small full size headphone (like the SR-60) that the other three give.
The OK2 is a PK2 on steroid.
OK1 vs OK2
The OK1 sound like bettered OK2. The OK1 improve in bass presence, upper treble precision and soundstage (especially height and depth). The two have the similar lower treble midrange response, with hints of sibilance when using not very good recordings. The OK1 give better sense of refinement, imaging and instrument separation. Instrument placement, especially, is top notch. Resolution is high too for a dynamic driver.
The OK1 don't fall short to the recabled Grado SR-60 in soundstage size.
PK1 vs OK1
PK1 are warmer, with thumpier midbass, but not much bloat as the SR-60, which makes for a gradoish sound compared to the neutral OK1. The PK1 also reach lower frequencies compared to the OK1. Vocals are fuller with the PK1, mostly due to a midrange emphasis (probably around 2kHz, adding vocals presence and sweetness, and part of acoustic guitars body), but without the same crystal-clarity provided by OK1. Soundstage is wide in both cases. The PK1 have slightly wider soundstage, the OK1 have better instrument separation and placement, which sounds cleaner as the midbass doesn't get in the way, but also because treble seems more extended and to have more quantity in the cymbals region.
The OK1 are more transparent, and certainly do better with classical and jazz. The PK1 sound more "effortless" with rock, thanks to the stronger (but not bloated) midbass energy.
OK1 vs ER4P
The Etys are brighter. They have an "empty" lower midrange. The ER4 have very deep bass, overcoming that of OK1 and PK1. The ER4P have too strong upper midrange and treble, and too much sibilance. The OK1 are not totally free from sibilance, like instead the RE1 are, anywy the RE1 achieved this only with a high treble recession (at 6-7kHz).
The ER4P have more upper mids/lower treble volume, due to spikes, which makes for a shriller sound. The OK1 retains the same level of detail of the ER4P, but without the same spikes. Thus, sibilance is a lot less sharp. This is also helped by them being out of the ear: when IEMs are sibilant, they are more painfully so due to them being closer to the eardrum. The Etys grate a lot due to this reason.
The flatter response that OK1 have over the ER4P gives a less analytical sound. Both ER4P and OK1 have tight bass, but while the bass is "right" with the OK1, and would have better quality (definition and depth) with Etys, it's overwhelmed by treble in the latter case.
PK1 with ER4P
The PK1 have more energy and fullness, especially with rock. The Etys are more glaring, ready to reveal any kind of artifacts. Everything is more separated and less blurry with Etys.
OK1 vs RE1
The RE1 sound darker and more romantic, slow paced. Anyway, they miss quite a few details that OK1, Etys and PK1 reveal. The OK1 are more forward than the RE1.
The RE1 have more bass quantity and depth compared to the two open earbuds. They seem to miss some nuances in the upper end. Treble is severely recessed and the overall tone loses something. The OK1 scale a lot better detail-wise. Soundstage is very big with both.
The OK1 and RE1 are different flavors. The RE1 occurred to me when I was sickened from sibilance, and I enjoyed them like a bliss. I listen to very bad recording rock from the 60s and 70s, and it's hard to find non-sibilant IEMs. Anyway, later on I realized I needed to increase volume too much to make treble exciting.
Treble has more volume, more "color" and nuances with the OK1, which are my favorite choice for neutrality. For classical the OK1 sound very good. Listening to Shostakovic, the increase in details and instrument separation is very noticeable. The OK1 give a better sense of "choral" work. With classical, the RE1 sound dark when not needed. The OK1 sparkle more.
The OK1 are instead a bit cold for rock, where my main choice would be the PK1.
***UPDATE: OK1 vs Stax SR-003***
For this comparison I used the OK1 amped with the Headsix, and the SR-003 amped with the SRM-Xh. The Xh is a vintage amp that should be better than the stock, portable SRM-001 that comes with the portable babystax, but not as good as the SRM-252 that comes with the newer Stax SRS-005A package.
The Headsix pairs especially well with the OK1 with its slightly warm and smooth sound.
The OK1 are dry, while the SR-003 are warmer, romantic, seductive, like a sunset and a red painted sky.
The SR-003 are very colored (at least when using them with the headband), but in a very pleasant way. I prefer the SR-003 color over grado sound signature the PK1 have. The OK1 tend to add less to the music, and to let it flow freely. Both have very good soundstage and separation, but the SR-003 are in another league compared to everything else I heard. Their resolution, even with a simple iMod, was "educative", to say the least. The SR-003 are electrostatic, and that's interesting how they are very detailed with a dark sound, without boosting the upper mids and the highs (like Etymotic do). At this point, we don't need to describe the sound signature of the OK1 any further. The SR-003, instead, have an emphasis in the midbass and lower mids. The overall tone is very pleasing, but I could use less midbass. The lower treble on the Stax is very smooth, even if a bit subdued, and controls sibilance without killing the details like what happens with the RE1. The Yuins can be a little brash with the sharpest recordings. The Stax have rolled off extremes. The OK1 have more extended highs, but not bass. The Stax are enveloping, seductive, romantic. The OK1 are neutral, less "fun", more analytical/uncolored.
Being the Stax more resolving they make me aware of any kind of imperfections in the track (like artifacts). This is a downside for casual listening. These artifacts can still be noticed with the OK1, but you don't feel like you are spotting them, one by one.
I prefer the Stax (pretty much to everything I have heard), but I rate both very highly: they are so different to be complementary).
As a guess, I think the OK1 could do really well with the Lisa III and its bass knob (so that anyone could tailor the bass at their own will), or a warm tube amp.
The SR-003 (or the SR-001) could do a better with Audiocats modded SRM-001 (portable amp), or with the SRM-1 MkI (home stationary amps).
Conclusion
The OK1 are very transparent and not as colored as the PK1, and for this reason they might appeal a different range of people. Rock sounds "effortless" with the PK1. I think the PK1 color the music, adding similar tone to many albums The OK1 make themselves less noticed, but thin recordings can feel a bit cold. The PK1 are more neutral and refined than the SR-60 (see: Grado SR-60 review, in my signature).
The OK2 are very similar in sound signature to the OK1. They don't sound as big as the PK1 and the OK1, but they are close. The OK2 are a pretty good choice for going unamped, more so than the PK1 or PK2.
The RE1 keep hitting a sweet spot for me, where Neil Young, early Pink Floyd, some Yes albums, Van Der Graaf Generator lie, with their nasty sibilance as well as their wonderful works.
Tony
I'll add other AB comparisons I have done with other headphones I have been owning lately.
The earphones: PKs vs OKs
Like previously expressed by Kostalex, the OKs are slightly thicker than the PKs.
The Yuin OK series is much better looking, the earphones have metal parts, look sturdy and precious. I find the PK series a bit more comfortable when comparing them directly to the OKs. Both series are very comfortable as earbuds.
Presentation: PKs vs OKs
The OKs are a more homogeneous line compared to the PKs.
The PK1 and PK2 are very different, with the PK1 being warmer, more thumpy and midbassy than the PK2, and a lot bigger sounding.
The OK earphones share the same sound signature, while adding refinement and sound qualities to each step.
I feel the OKs start sharing a similar sound signature to the PK2, improving it.
PK2 vs OK3
I find these earphones very similar. The most noticeable difference between them is sensitivity. The OK3 are a bit less sensitive than the PK2. Using a MuVo and the OK3 I have to raise the volume of one notch to match the same volume of the PK2. It's a slight difference.
When I approached the PK2, I didn’t know what to expect. After reading Kostalex’ review (many months ago), I expected they sounded very similar to Koss KSC75. Furthermore, when I used to talk to Kramer about the Yuins, one year ago, I was figuring that the PK2 were “grado-like”. At that time, my only experience with a “grado” sound were the d-JAYS, which I profoundly disliked as innatural, due to the extremely nasal midrange and distorting electric guitars.
The PK2 are a lot more natural than d-JAYS (in the end I discovered that d-JAYS aren't gradoish, but this is another story). The PK2 are similar in sound signature to the Koss KSC75, but with narrower soundstage and cleaner sound, especially in the bass and midrange, where the KSC75 sounded muffled and dirty.
The PK2 are also more natural than the Grado SR-60, but the latter is bigger sounding and shows better instrument separation.
OK2 vs PK2 vs ER4P
The OK2 share the same sound signature as the PK2. Neither is bass heavy, but not as bass light as the ER4P (which used for constant AB with the OK2). Bass is not as deep as the ER4P, thus the OK2 might lack some impact compared to the Etys. The only open earbud design to have some deep bass in this review is the PK1, while other lose at bass extention.
Midrange is similar in both PK2 and OK2. The lower treble is slightly forward, which gives some sibilance with sharp vocalists like Freddy Mercury, but nothing dramatic, not as with the stock Super.fi 5 Pro and their treble spike, or the Etys and their “saw” frequency response.
Compared to the ER4P, the OK2 are free from the great sense of glare and “special effects” that Etys have. Stock ER4P are artificial, giving a fake sound signature and some sickening sense to the music.
The OK2 are slightly warmer than the ER4P and don't sound empty, like Etys do. The OK2 are quite detailed, but less and differently from Etys, that present details not meant to stand out.
I tend to like the OK2 and ER4P on the same level. The OK2 are more natural, the ER4 are more analytical and deeper. The OK2 have wider soundstage and more natural sound. The Etys would be superior if it wasn't for certain flaws that make them super-sharp.
More about the OK2 vs PK2:
Treble is similar in quantity on both OK2 and PK2, but more extended with the OK2. Both have less treble quantity than Etymotic ER4P.
The OK2 seem to me also more extended in bass than the PK2, giving better sense of rhytm.
The biggest differences between the two, anyway, come out when comparing the soundstage. The OK2 are widely out of the head, in the same league as the PK1 and the OK1. The PK2 (as well as the OK3) are in the head and don’t give the same feeling of using a small full size headphone (like the SR-60) that the other three give.
The OK2 is a PK2 on steroid.
OK1 vs OK2
The OK1 sound like bettered OK2. The OK1 improve in bass presence, upper treble precision and soundstage (especially height and depth). The two have the similar lower treble midrange response, with hints of sibilance when using not very good recordings. The OK1 give better sense of refinement, imaging and instrument separation. Instrument placement, especially, is top notch. Resolution is high too for a dynamic driver.
The OK1 don't fall short to the recabled Grado SR-60 in soundstage size.
PK1 vs OK1
PK1 are warmer, with thumpier midbass, but not much bloat as the SR-60, which makes for a gradoish sound compared to the neutral OK1. The PK1 also reach lower frequencies compared to the OK1. Vocals are fuller with the PK1, mostly due to a midrange emphasis (probably around 2kHz, adding vocals presence and sweetness, and part of acoustic guitars body), but without the same crystal-clarity provided by OK1. Soundstage is wide in both cases. The PK1 have slightly wider soundstage, the OK1 have better instrument separation and placement, which sounds cleaner as the midbass doesn't get in the way, but also because treble seems more extended and to have more quantity in the cymbals region.
The OK1 are more transparent, and certainly do better with classical and jazz. The PK1 sound more "effortless" with rock, thanks to the stronger (but not bloated) midbass energy.
OK1 vs ER4P
The Etys are brighter. They have an "empty" lower midrange. The ER4 have very deep bass, overcoming that of OK1 and PK1. The ER4P have too strong upper midrange and treble, and too much sibilance. The OK1 are not totally free from sibilance, like instead the RE1 are, anywy the RE1 achieved this only with a high treble recession (at 6-7kHz).
The ER4P have more upper mids/lower treble volume, due to spikes, which makes for a shriller sound. The OK1 retains the same level of detail of the ER4P, but without the same spikes. Thus, sibilance is a lot less sharp. This is also helped by them being out of the ear: when IEMs are sibilant, they are more painfully so due to them being closer to the eardrum. The Etys grate a lot due to this reason.
The flatter response that OK1 have over the ER4P gives a less analytical sound. Both ER4P and OK1 have tight bass, but while the bass is "right" with the OK1, and would have better quality (definition and depth) with Etys, it's overwhelmed by treble in the latter case.
PK1 with ER4P
The PK1 have more energy and fullness, especially with rock. The Etys are more glaring, ready to reveal any kind of artifacts. Everything is more separated and less blurry with Etys.
OK1 vs RE1
The RE1 sound darker and more romantic, slow paced. Anyway, they miss quite a few details that OK1, Etys and PK1 reveal. The OK1 are more forward than the RE1.
The RE1 have more bass quantity and depth compared to the two open earbuds. They seem to miss some nuances in the upper end. Treble is severely recessed and the overall tone loses something. The OK1 scale a lot better detail-wise. Soundstage is very big with both.
The OK1 and RE1 are different flavors. The RE1 occurred to me when I was sickened from sibilance, and I enjoyed them like a bliss. I listen to very bad recording rock from the 60s and 70s, and it's hard to find non-sibilant IEMs. Anyway, later on I realized I needed to increase volume too much to make treble exciting.
Treble has more volume, more "color" and nuances with the OK1, which are my favorite choice for neutrality. For classical the OK1 sound very good. Listening to Shostakovic, the increase in details and instrument separation is very noticeable. The OK1 give a better sense of "choral" work. With classical, the RE1 sound dark when not needed. The OK1 sparkle more.
The OK1 are instead a bit cold for rock, where my main choice would be the PK1.
***UPDATE: OK1 vs Stax SR-003***
For this comparison I used the OK1 amped with the Headsix, and the SR-003 amped with the SRM-Xh. The Xh is a vintage amp that should be better than the stock, portable SRM-001 that comes with the portable babystax, but not as good as the SRM-252 that comes with the newer Stax SRS-005A package.
The Headsix pairs especially well with the OK1 with its slightly warm and smooth sound.
The OK1 are dry, while the SR-003 are warmer, romantic, seductive, like a sunset and a red painted sky.
Being the Stax more resolving they make me aware of any kind of imperfections in the track (like artifacts). This is a downside for casual listening. These artifacts can still be noticed with the OK1, but you don't feel like you are spotting them, one by one.
I prefer the Stax (pretty much to everything I have heard), but I rate both very highly: they are so different to be complementary).
As a guess, I think the OK1 could do really well with the Lisa III and its bass knob (so that anyone could tailor the bass at their own will), or a warm tube amp.
The SR-003 (or the SR-001) could do a better with Audiocats modded SRM-001 (portable amp), or with the SRM-1 MkI (home stationary amps).
Conclusion
The OK1 are very transparent and not as colored as the PK1, and for this reason they might appeal a different range of people. Rock sounds "effortless" with the PK1. I think the PK1 color the music, adding similar tone to many albums The OK1 make themselves less noticed, but thin recordings can feel a bit cold. The PK1 are more neutral and refined than the SR-60 (see: Grado SR-60 review, in my signature).
The OK2 are very similar in sound signature to the OK1. They don't sound as big as the PK1 and the OK1, but they are close. The OK2 are a pretty good choice for going unamped, more so than the PK1 or PK2.
The RE1 keep hitting a sweet spot for me, where Neil Young, early Pink Floyd, some Yes albums, Van Der Graaf Generator lie, with their nasty sibilance as well as their wonderful works.
Tony
