While normally the reason I’m interested in a pair of Vietnamese IEMs is because they’re made in Vietnam, AYA’s first product attracted me for a very different reason: it’s bullet-shaped. In fact, the housings were made from Makarov bullets, with the brandings still very visible.

Step 1: Bullets. Step 2: Nightingale.

AYA Nightingale YK-S, so from that idea, a Vietnamese earphone maker was born. Without a prominent name at first, they literally advertised themselves as “bullet in-ears” on our online forums/fb groups. I almost thought the products were just another “unique bling bling” idea from the Chinese, but upon contacting the owner, I was quickly proven wrong. The earphones were made in Vietnam.
Yet nice-looking as it is, the bullet in-ears that carry AYA’s namesake sounded nothing out of the ordinary. Read: nothing out of the “cheaply priced, V-shaped, nicely package” that used to be the norm in my country. Thankfully though, AYA wasn’t entangled too much in the endless baseless arguments that often plagued our forums. It only took them one or two years (and 3 generations of bullet IEMs) to produce their next product, the first to get into the mid-range market: Nightingale YK-S.

Not priced for the mass

Looks great. Sounds polite.

Sold for $200, the AYA Nightingale YK-S isn’t priced for the mass market in Vietnam, where you can get a perfect bowl of pho for $2 (instead of at least $10 in the US). Its sound doesn’t aim for the mass either: instead of going for that dance-y, hip-hop-y sound that has ensnared the majority of our youths, the YK-S was made for Vocals music first and foremost.
The fact is just clearly evidenced from the bass. In comparison to its brother (the bullets), YK-S can almost be said to be bass anemic. Having a warmish source like the Chord Mojo or a ODAC-O2 with a Burson op-amp installed will help provide just enough bass for EuroPop or Lady Gaga, but still it’s not Sony or Beats or V-Moda. There’s just no comparison.

Clarity and timbre in the same package. 

But moving onto the higher frequencies, you can see clearly where the YK-S shine. It has a full and smooth mid-ranges, perfectly made for Frank Sinatra, Andy Williams or Bee Gees. Having previously used a Sony XBA-H3 and Audio Technica IM02 for those crowded, lonely Singapore train rides, I feel like the YK-S bring a feeling of timbre to the mids. It I was listening to an electronic, re-produced sound on other in-ears before, I’m now listening to the suited men singing in their natural habitat. A real feat, considering that the YK-S uses Balanced Armature drivers .
As for the soundstage and details, the trebles did a fine job. Not perfect, just fine. The soundstage expands in width, not in depth. I couldn’t “see” rockstars moving their hands during MTV Unplugged shows, nor could I hear the bite that removes the boredom from stadium AOR. Yet this weakness fits really well into the YK-S’ raison d’être: there are no sibilance of any kind when amped by a Mojo, and thus no ear-shredding when Candice Nights sing her “s” sound.
​As with the male voices, the ladies also shine on AYA’s IEMs: each enunciated word sound full and a bit sweetened. The very songs that sound lifeless and out of touch on the typical Vietnamese IEMs have become alive on the Nightingale YK-S. Alive, not lively though.

Too much wire and too much song (that song actually goes great with the YK-S).

Well in terms of sound that’s practically all the YK-S does. Of my favorite genres, the YK-S is clearly not for Metal. The way AYA’s newest IEMs blend bass and mids, and mids and trebles just does not allow for very good riffs/licks. There was no “bite” for electric guitars – though the upper mids and trebles can still provide some airy feel for male Vocalists and some sparkles here and there for some instruments. Overall, I feel for Rock, Jazz Fusion and Metal the YK-S didn’t provide enough upper-freqs energy.
The bass-oriented genres, as I’ve mentioned before, are just not for the YK-S. The bass-boost on the C5D or iFi iCan might help, even a Bursonized Objective2 helps bring about a fuller low-ranges. But no matter how you tune your system, the YK-S will never become powerful in the search for an explosive EDM experience. The genres that this pair of IEMs can play well never stray too far from relaxing Vocals-focused music: instrumental piano, instrumental guitars, instrumental saxophone (oh this one was great), faux classical (like those from Paul Mauriat), baroque Classical, non-Wagnerian Classical etc.
Which is not quite a problem for me. But still a very bold move, considering in Vietnam we’ve songs like this:

The tradition of a nice package, discontinued

What our typical V-shaped IEMs lacked in sound, they made up for in packaging. The YK-S goes the opposite way: I really like its sound, but the packaging was not quite impressive. The phones were shipped in a small case that also included 3 pairs of extra tips. The case itself was put inside a paper box that was itself covered by a cover… I know that doesn’t make a lot of sense, so this is the pic:

The cover, the box, the case.

So there’s quite some drawings on this cover, trying to look artsy and such. I’m not too impressed though. The bullets were shipped in this beautiful wooden box:

Well at least there’s the “Designed and Manufactured in Vietnam” that always make me feel proud each time I see it.

But the phones looked extraordinary

AYA’s website showed that they’ve done quite a lot of work with the housing. The results are astounding: the housings shine, not in a plastic-ky way but in a orb-y way. Upon receiving the product, I literally couldn’t stop staring at it for like 1 or 2 hours (Bee Gees was on, so of course that was as true as any sentence with “literally” in it). The finish was kind of like the “holy qilin” necklace that my wife bought me when we were still dating. In combination with a pair of white silicon tips, the YK-S has an undeniably high-end look.

Always appreciate soft, nice-feeling earhooks and a L-shaped plug. Always.

Comfort was also great. The earhook is made from some kind of soft, nice-feeling plastic, the housing was very lightweighted. You can easily change the cable, which use the same kind of connector as Noble’s and other popular IEMs. The plug is L-shaped too, so no worries when you use the YK-S with your smartphones or DAPs.
Lastly, the YK-S have truly great noise isolation. Tired of the boring sound from my QC15 on the long, 3-legged flight from my beloved Denver back to Vietnam, I decided to wear the YK-S on the way from Hongkong to Hanoi. To my surprise, the “bzm bzm” engine sould wasn’t as prevalent as I’d thought. It was certainly waaaay better than the Jelly Galaxy (a horrible sounding IEMs that somewhat put our country on the audio map because it had an indiegogo) or the XBA-H3.

The next step

As with the Notes Audio AT10, the Nightingale YK-S marks a whole new era for Vietnamese earphones. From a place where we almost had nothing special to speak of, we now have 2 truly great earphones to enjoy.

The brave and the bold.

Not that they are anything alike. The AT10, while still very hi-end in my humble opinion, is still a IEMs product that everyone can enjoy. The YK-S boldly go in the direction of Vocals and almost Vocals-only, greatly limiting its potential market in my country. Priced a few bowls of Americanized Pho higher, it will surely bring about a much difficult thought process for any Vietnamese interested.
Yet for anyone who enjoys the oldie, Vocals-focused music, or anyone that spends most of their time on slower, more relaxing music, the YK-S is a perfect choice. The beauty of its finish, the comfort over an extended session and the overall premium feels of the phones totally justify the price. It’s selective, yes, but selectively great for the right listeners.

Unlike this pic, the future is bright and full of hopes.

Looking forward, I’m really, really hoping for more products like the YK-S. Despite my country’s terrible traffic, lackluster medicals and aggressive interwebz, I still believe the people deserve the best domestically-made earphones for their enjoyment. Here in Vietnam we love the Carpenters, we love the Bee Gees, we love Celine Dion, we love Kenny G and we love many, many Vietnamese singers whose melodies come much closer to those classic artists than the modern HipHop/EDM-infused “artists” that compete for YouTube records.
And that means the YK-S should find its way to a lot of music lovers.

Source : head-fi.org