The earbud form factor is fantastic when utilised correctly and it takes a lot of tweaking to get just right. I’m delighted to report that Shozy have done a splendid job with the BK; it is an evolution over the Cygnus with greater balance while retaining that organic, slightly analogue character. I would still categorise the BK as a slightly darker sounding earphone, but they find much better balance than the Cygnus, especially with regards to treble presence. And behind the final result is an intriguing design process that makes the BK all the more impressive. Where the vast majority of earphones and earbuds put emphasis on the driver(s), how many there are, their special materials, maybe even their exquisite tuning, few boast nearly as much about the surrounding elements. The BK is rather the opposite, Shozy stressed to me how they focussed on the cable, housings and acoustics rather than just the driver. This philosophy was refreshing; In fact, it really explains why so many earbuds sound so off. Because earbuds are completely unlike earphones, they barely seal and resonances are far more out of check due to the larger air space. And anyone who has experience with speakers will tell you that the housing and dampening make just as much difference as the driver itself if not more. Luckily, the BK is an exemplary example of such attention to detail, it is simply a terrifically tuned earphone.
As always, this will be the most subjective aspect of my review, I have no measurements to back up my impressions and they are also subject to change due to environmental factors. Shozy are big on burn-in, I suppose their handcrafted earbuds with their enormous 14mm drivers will be more susceptible than most to acoustic changes over time. In the month or so that I’ve had the earbud in my possession, it has received over around 200hrs of burn-in from my Fiio X7. Subjectively, I feel the BK now has slightly more resolution and sounds slightly smoother. The midrange has gained slightly more clarity and the low-end some extra definition. Shozy state that these changes can be attributed to oxidation of the cable and connectors in addition to mechanical change within the driver itself. My guess is that the foam covers have gotten slightly thinner from wear over time, perhaps another reason why Shozy don’t include replacements in the box. Whatever the cause, the BK has had a notable response to burn-in, not a night and day difference as expected, but bigger than most earphones I review.
The BK exemplifies Shozy’s analogue but tasteful tuning as the most natural sounding earbud I’ve ever heard. And in terms of realism and musicality, the BK also bests some much more expensive in-ear earphones too. The BK is very balanced and just slightly U-shaped, with bass having the most emphasis. It is tonally in-between the slightly mid-forward 1More E1008 and the more bass focussed Cygnus which I found to be a really nice sweet spot. Mids are very even and quite full-bodied. While they aren’t thick, closed off or muddy to any extent, they make a lot of in-ears sound thin and unnatural by comparison.
Most earbuds are designed exclusively for home use, reasonable given that they provide almost zero isolation. But earbuds have some place on the go, the library for instance, where one can enjoy music but also maintain awareness of their surroundings. So where most earbuds pursue huge impedances with the intention of being driven from a dedicated amplifier, the BK is rather very sensitive and easy to drive from almost any source. The BK has a huge sensitivity of 115dB and a very low impedance of 16ohms. That makes it as sensitive as the Campfire Jupiter though, due to their lack of seal, they don’t sound nearly as loud at the same volume levels. The BK is similarly easy to drive as the Cygnus and considerably more sensitive than the 1More E1008. Compared to the 150ohm VE Zen 2.0, the BK is the far more versatile earbud though it ends up being just as source sensitive.
And regarding source sensitivity, Shozy actually requested I put emphasis on pairing and synergy with this earbud. Because while driver setup and impedance are usually a pretty reliable indicator of source sensitivity, the single dynamic driver BK’s are actually very picky. That’s not to say that the BK experiences impedance swing like the Sony XBA-40, but their transparency does mean their tonality is quite source influenced. In subjective listening, and according to my preferences, I found the BK to find best synergy with my Oppo HA-2 which is probably my brightest source. From the Oppo, the BK sounded slightly more open and clean through their midrange. Treble, which is a bit over-attenuated by the foam covers, is brought forward ever so slightly more, granting a more ethereal soundstage and a little more air with songs that call for it. The Fiio X7, utilising the same DAC chip, was also quite a nice pairing though I found the AM2 module to be a bit warm for the already slightly warmer BK. The Chord Mojo told a similar story, while hardly a laid back or closed off sounding source, the BK achieves more balance from more analytical sources than musical ones. Users of newer IOS devices will also be delighted to hear that the BK sounds tonally fine from the stock output, the BK is very easy to drive and benefit from my iPod Touch 6G’s slightly brighter sound though the earbuds were noticeably less revealing and nuanced as opposed to the Oppo. Despite being a very nice sounding phone in general, my HTC 10 didn’t actually pair well with the BK. I found it to sound a bit congested and lacking dynamics, perhaps the 10’s higher output impedance is affecting the BK’s tonality, I can’t say for certain, but the BK found better synergy elsewhere. So while the BK doesn’t require an amplifier, they definitely benefit from a slightly brighter source of low output impedance and scale very well with higher end sources. And though they won’t realise their full potential, I still think the BK sounds better from lower powered portable sources than similarly priced earbuds of higher impedance such as the Yuin PK1 and VE Zen 2.0.
Soundstage, Imaging and Separation –
It’s here that we start to see that open form-factor working its magic, the BK doesn’t produce the most all-encompassing stage, but it is exceptionally natural and open without compromising imaging and coherence. The BK’s stage is well-rounded and expansive, they are slightly depth focussed but width easily reaches outside the head and does so frequently. The BK’s more extended treble and increased resolution make it the appreciably more open sounding earbud compared to the more intimate Cygnus, also aiding separation. The E1008 is more spacious still but the more balanced BK is more separated and images just as well. Listening to Massive Attack’s “Paradise Circus” revealed accurate instrument placement and a strong centre image that bested both the E1008 and Cygnus. In addition, directional cues were pretty sharp and bass was appropriately expansive without becoming too woolly. Imaging still doesn’t match earphones like the 1More Quad Driver, but among earbuds, the BK does a great job. As aforementioned, separation is fantastic; booting up MGMT’s “Time to Pretend” and the BK breezed through complex synth that most in-ears mince together. In-ears simply don’t do soundstage like earbuds do, it’s like comparing closed to open-back headphones.
The low-end on the BK is well tuned, agile and snappy with great PRAT. Buyer’s need to consider that the BK doesn’t have a huge bass emphasis, rather, bass is slightly lifted from neutral and organic in nature with a touch of deep/mid-bass focus. For my tastes, bass quantity and emphasis is pretty spot on and I think a lot of listeners will find the same. The Cygnus does sound a fuller for those who prefer a bit more low-end, though its more mid-bass focussed response is looser and lacks the fabulous texturing of the BK. Being an earbud, the BK has just average sub-bass extension and no real slam to the lowest notes. Of course, few earbuds really hit that deep, but a few models like the E1008 do have slightly more extension. That being said, every frequency above that is really well done, the BK has a very linear bass response with minimal flab or bloat, far less than the Cygnus before it. The low-end is also very tight without leaning out, something the E1008 struggled to pull off. When listening to Earth, Wind and Fire’s “In the Stone”, the BK’s provided fantastic texturing that easily bested both the Cygnus and E1008. The BK also had the fastest response with great pacing and very impressive definition, making the Cygnus sound a bit sloppy by comparison. They also possess great bass detail retrieval, the BK’s low-end was considerably tighter and more defined than the more expensive 1More Quad Driver for instance and bass resolution was fabulous with great clarity to individual notes and sweeping tones alike. Similarly, when listening to Arcade Fire’s “Everything Now”, a song that has a slightly more monotonous bass line, the BK did a great job discerning details that the Cygnus skipped over entirely. So besides extension, there’s not much to dislike with the BK’s bass response. Of course, the BK is lacking the resolution of more expensive models like the 64Audio U3, but the earbud provides a truly sensational mix of linear tuning and quality that dismantles similarly priced in-ear models and appreciably outperforms similarly priced earbuds too.
Despite having such a great low-end, the BK’s midrange might be their most impressive aspect. I’m very picky about my midrange tuning, so many earphones come off as unnatural, thick or thin. I think a lot of earphones are too focussed on impressing with their pounding bass and soaring highs that they forget the majority of the information in most songs is contained within the midrange. The BK immediately impresses again with its linearity and realism. While mids do carry a slightly darker tone, they have great clarity while retaining impressive amounts of vocal body; they don’t sound as thin as the Magaosi K3 Pro, Fiio EX1 2nd Gen and even the 1More Quad Driver. This is probably the most notable aspect of their performance, that ability to present so much clarity while retaining that organic, natural tone. Lower mids are slightly warm with just a hint of bass spill though male vocals never sound muddy or thick, just slightly more full-bodied. Listening to Commodore’s “Easy”, the BK produced clear, forward vocals with nice layering and projection. They were slightly more balanced than the more bass-forward Cygnus and clarity, realism and timbre were all improved on the BK. Upper mids sit just slightly behind lower mids and retain that same kind of full-bodied presentation. The BK absolutely flatter female vocals, they have the best upper-midrange tuning I’ve heard on an earbud. Even thinner Asian vocals, which sound a bit thin and nasal on the Cygnus, sound lush on the BK while retaining clarity and detail. Similarly, thicker western vocals avoid sounding chesty or unconcise, the BK’s are more tonally consistent than the Cygnus and more natural while also sounding cleaner and clearer. Listening to “Erase” by Hyolyn, Jooyoung and the BK produced great separation between main and backing vocals and both male and female vocals were delightfully balanced. The BK also created a very pleasing rendition of strings that was smooth and unfatiguing but also clear and composed, their midrange is tonally excellent.
And quality wise, the BK’s are similarly impressive, the BK’s are more transparent and revealing than the very technically proficient 1More E1008 while also being more tonally pleasing. Resolution is also good but they are missing a touch compared to similarly price in-ears, most apparent with layering and the precision of background details. Detail retrieval is very good, the BK isn’t as aggressive in its detail presentation as the slightly peakier Cygnus, but I wouldn’t consider them to be laid-back either. Listening to George Michael’s “Faith” and the BK did a much better job than the Cygnus at reproducing each guitar strum and detail. And though the Cygnus had more forward treble details, their outright detail retrieval and resolution clearly lagged behind the more expensive BK. The E1008 told a similar story with less resolution and considerably less clarity than the BK. And while the E1008 has similar detail retrieval to the Cygnus, the BK is easily the more detailed, resolving earbud.
The high-end is where the BK falters a bit, perhaps it is a limitation of the earbud form factor at this time as earbuds don’t do end to end extension particularly well in general. The BK is among the best earbuds I’ve heard in terms of high-frequency response though they don’t extend and resolve quite like in-ears around this price do. Extension is just good in the grand scheme of things, they certainly extend further than the Cygnus and similarly to the dual driver E1008, but that really high-frequency detail is either recessed or missing. That’s not to say that the BK is missing detail in the slightest and this isn’t noticeable in the majority of songs, but the BK does have a roll-off at the very top. Tonally, treble is very natural as with the rest of the sound, notes have nice body and texturing to cymbals, strings and wind instruments is very pleasing. Lower and middle treble detail retrieval is also impressive, they aren’t super aggressive in their presentation, but a slight lower treble bump does give them just a little extra crispness. Middle treble, in particular, is considerably more resolving than the Cygnus, which rolls off sooner and the E1008, which gets uneven in the highs. The BK doesn’t possess huge air but they do have some sparkle and treble sounds generally clean and separated. High-frequency resolution still can’t match really good in-ears around this price, I still prefer the response of the RE-600 for instance, but the BK’s linearity and texturing can be favourable to the peakier Quad-Driver and the very lower-treble forward Pinnacle P1 depending on preference. They do improve when removing the foam covers though the tonality is skewed bright with a significant loss of low-end that kind of ruins their splendid tuning. Some may prefer this sound, however, and there are plenty of different covers users can experiment with to achieve their desired sound. Of the Heigi donuts, full foams (without removed centre), Monk+ foams and 1More silicone rings, the pre-installed covers were the most “correct” to my ear though high-end extension and resolution was compromised. It’s a trade-off and listeners who prefer a more mid-forward sound will definitely enjoy the BK with the Monk+, 1More or perhaps no covers at all.
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