Yinyoo BK2 Earbud

Disclaimer:  I purchased the Yinyoo BK2 as the Black Friday lucky bag special from Wooeasy Earphone’s Ali Store.  It was recommended to me by the rep having recently reviewed a string of earbuds.  I was told it was an earbud, but was given no additional details prior to its arrival.  I paid the full asking price for the lucky bag which turned out to be a roughly 50% discount compared to the current asking price of $59.00.    Thoughts here are my own and not coerced in anyway.


Not too long ago, I reviewed a ShoonTH, a couple of NiceHCK, and the Astrotec Lyra Classic earbud.  It had been too long since I gave earbuds much thought and quite frankly the quality has improved by the same leaps and bounds we have seen in other segments of the earphone market.  I found myself liking them more than I thought I would due to their enormous stage and finding them advantageous at times due to the lack of isolation.

The BK2 fits between the two NiceHCK offerings and about 1/3 the price of the Lyra so might be a good middle ground for those after something a bit better built than the low end plastic shells we are all used to and bit less expensive than something like the Astrotec depending on how it sounds.


Unboxing / Packaging:

My Bk2 came packaged in a red lucky bag with the standard blue and silver Yinyoo pressboard box inside along with an additional cable sent as a gift.   The additional cable was not meant for hte bk2 as it has pre-formed earhooks so won’t be included in this review.  (I’ll look at it another day).    Opening the box reveals a small black rubberized soft case bearing the Yinyoo logo.  This style packaging has become the standard for most of the Ali vendors of late it seems as more and more of what arrives at my desk is packaged in exactly this same fashion.   Inside the case are the buds, cable, 4 pairs of foams (black),  4 pairs of donut foams (red), and a shirt clip.    The kit is reasonably complete and while a few have had a leather cable strap in the kit this is of little consequence to many and easily added if desired.



The Bk2 is a typical earbud shape that I can best describe as the bowl and barrel design.  The driver is held in the bowl which is roughly 19mm wide in order to hold the 14.8mm driver. The grill is held to the bowl with a black plastic ring that also provides a smooth surface where contact with the ear is made.   the shell has one large vent at the bottom that is hidden from view by the mmcx connector on the cable when it is attached.   The bowl portion of the shell stands roughly 6mm tall.  The rear of the earbud is the barrel portion which stands another 7mm tall and provides the connector which is pointed straight down and is centered front to back.  I much prefer this style to the current offset designs as in my ear it stays in place better.    Faceplates are marked with the Yinyoo logo, name and either L or R respectively.   The buds weigh very little, but do feel solid with no flex.









The bk2 is a single 14.8mm dynamic driver with a nominal impedance of 16Ω  and a listed sensitivity of 102dB.   A search for additional details on diaphragm material etc. yielded little.   The driver works well directly from a cell phone and doesn’t really benefit from additional power as I found it easy to over-power when connected to higher power sources.  When doing most of my testing I used the Opus #1s and AK70Mk2 on low gain as it was the best compromise with the Bk2.


The provided cable is silver plated copper in a twist pattern.  Starting with the jack, the BK2 has a straight 3.5mm jack with a brushed aluminum housing and fairly short strain relief.   The wire is 4 core twisted up to the splitter and twisted pair above.  The splitter itself is a small brushed aluminum barrel marked bk2 on the side.  No strain reliefs above or below the splitter are present.  A chin slider is provided in the form of a small brushed aluminum ring that mates to the top of the slider and moves easily while still staying in position well.  This is a nice touch as I find all too often the sliders are either so difficult to move I worry about breaking the cable or so easy to move they do little good.  Termination is mmcx connectors in brushed aluminum housings one marked in red to identify L/R orientation.  Overall, the cable is well done and appropriate to an iem at this price point.









The Bk2 sits well in the ear and aligns well with the ear canal.  Once the chin slider is adjusted, I had no trouble wearing the BK2 while walking, jogging on the treadmill, or working around the house.  This is as much as I can ask of an earbud design.   Those with smaller ears may find the size a problem as the bowl portion of the earbud is on the large side.


All of my listening notes are done with donut foams installed.  If you use the bk2 with solid foams, except some differences between my notes and your listening experience.



Sub-bass which is tough for any non-sealing design is present but not prominent and roll-off below 50Hz begins to be pretty evident at times.   On the upper side, the sub-bass moves into the mid-bass without a hump and is nearly linear all the way through the bass.   Detail is good but attack is slightly quicker than decay leaving it sounding just a touch slow at times.   Overall, it is nice to see an earbud that manages to have good bass representation without sealing and without pushing it so far forward in the mix to drown out everything else.


Lower mids follow in linear fashion from the mid-bass and a mild bass bleed does lend a bit of warmth without obscuring much of the lower mids.  True mids are slightly recessed but still manage good detail retreival.  Vocals sound like you are sitting in decent seats at the arena, but didn’t quite spend the big bucks to get the first 5 or 10 rows.   At times this comes across very nicely while at others it causes a little bit of a sense of loss of intimacy.     Upper mids are roughly on the same level with the true mids and lower treble so most vocals are equally represented which I actually found nice as it does not put male behind female or vice versa as is commonly heard on some tunings.


The lower treble stays in line with the upper-mids until we reach the true treble where we hit a small spike centered around 6kHz.   This isnt enough to really get screachy but is enough to make you take notice of it.   It both adds some air and potentially makes it a bit harsh in the same motion.   A second spike around 12kHz also brings back a bit of sparkle to an otherwise only average treble extension.   Neither of these spikes are large enough to really be nasty unless the track is already prone to it.


Soundstage / Imaging:

Soundstage is above average with good width and depth and some height.  Depth is slightly better than width as at times the stage can seem a touch narrow but not cramped.   Imaging is above average with instrument seperation being better than expected and even on full orchestral pieces maintains good space.  There are occasional overlaps in orchestral pieces which is not atypical for a single driver iem.    I did find a tendency to get a little congested on tracks with a heavy bass line and lots of activity so those looking for a basshead bud may  want to keep that in mind.  Those looking for more balance will probably have little trouble with this as it had to be induced with a bit of eq tampering and tracks that are more or less designed to cause that problem.



Yinyoo bills the BK2 as a flagship earbud so it is only fair to compare against other flagships.  Having said that it is also fair to remember that the Yinyoo Bk2 retails at $55 which is substantially less than some of the competition we are comparing it with.

vs NiceHCK EBX

The Bk2 gets somewhat outclassed by the EBX as the build quality is better on the EBX and the sound a bit more refined and detailed.  Here the difference in $50 and $100 spend is evident.

vs MrZ. Tomahawk

The Tomahawk was the best of budget earbud for awhile and has been my reference point for most others.   The Bk2 is better controlled with less bass bleed and less tendency toward harsh treble than the Tomahawk.    Overall, the BK2 is a better earbud than the tomahawk at roughly the same money and should displace the Tomahawk for many listeners.

vs NiceHCK Eb2

The EB2 is the current champ for best budget earbud and the BK2 won’t displace it if only because the bk2 is considerably more expensive without being monumentally better in any measureable department.  The Bk2 feels more solid in construction while the EB2 represents a better value sound wise as it shares the driver and sound signature of its more expensive sibling the EBX.

Vs Astrotec Lyra Classic

Lyra Classic has better tonality then BK2 and a bit more detailed sound while extension is slightly better on the Bk2.   The Lyra has a more refined sound than the BK2 but the two are more similar than different in signature.


Thoughts / Conclusion:

Yinyoo is marketing the BK2 as a flagship grade earbud and it certainly has the build quality to make that claim.  The cable is good but not quite on par with the build quality of the buds themselves (based partially on the lack of strain relief at the connectors and the splitter).      The Bk2 has a near neutral signature with good detail, soundstage, and imaging but suffers some from only average treble extension.  In the overall, I find the  bk2 to be a very comfortable, very listenable earbud that will check the right boxes for many.  Its most direct competition is the EB2 which has a slight advantage in detail retrieval and sound quality but can be problematic for those with smaller ears or for use during periods of activity.   The bk2 stayed in place without worry while using the treadmill and other exercise equipment which had been a bit of an issue with the ebx and eb2.      If you are in the market for an earbud, the bk2 should be on your list to audition, it does a lot well and costs very little.