[Ojisan]

Wowsers these are AWESOME (speed and detail unmatched by anything I have heard...)

Whilst it would be unfair for me to wax lyrical about the AK Zero1 IEMs given my extremely limited exposure to them, from what I can gather there are a few elephants in the room that might need be addressed.

Firstly - I believe good audio parts manufacturers build for the resultant sound (after 'break-in/burn in, also known as 'settling' of the product), rather than the 'out of box state'.
It is fairly easy to establish that the few graphs measuring the performance of these IEMs (so far) have been done without much 'break in', even to the point of having very obvious channel imbalance generally seen in the 'planar' driver range of the sound spectrum..
This could simply be that they were not broken in with a mono'd sound source, and, ever since the Beatles established to the masses a 'layout' for setting a stage, lets face it.. different frequncies come from Left/Right speakers in 'typical music'.
With 'just a little break in' the differences in measured performance across the channels might have contributing factors that have made this so, but also leads one to concur that 'with more break in time' those 'peaks and troughs' on the graph might totally smooth out. (likely 'as intended')

I myself have witnessed various driver material compositions as altering the 'break in time', and certainly different technologies (such as the included balanced armatures/dynamic driver and planar unit) taking different amounts of time to 'find their best' performance...

The most overt showcasing of this, for me, was some metal foil dynamic drivers that took 1200 hours to 'tame their screechy peaks'.. (after which point they sounded considerably better than they did 'out of the box'.

Small dynamic drivers of a hard composite can take a long time to find their best stride.
Unbroken in planars sound HORRIBLE to me.
I have too limited experience of balanced armatures, but when the tech first came to market, my experience was against my expectation that they would not need much/any break in at all...

This isn't acclimatisation as many from the audio science sub section will demand... (and I have a back ground in tertiary psych going back to the early nineties... ; please 'lets not argue our subjective opinions on this... )

Generally I won't listen to anything straight from box...
But 'wowsers' these are so good... (even without ANY front to back imaging as a new pair 'give')

So - what was is my experience with only thirty odd hours on them... (mostly mono'd prodigy fat of the land and some holosync 'meditation' tapes, some orchestral pink floyd, and live performance by Dead Can Dance...)
OK- straight from box- incredible detail and speed, great left to right imaging.. not much reach beyond left ear/right ear boundaries... also atrocious decay that removes all positioning information as sounds do not drop off gradually but, like a square wave.. 'now you hear me/now you don't)
3-10 hours - HEIGHT info has kicked in... (very unusual, this usually is very gradual (if at all for 'many headphones'), and typically turns up slower than 'front to back' soundstage.. (which still is only a few feet deep (if on a stage), slightly better than out of box, but still not really there at all)
30 hours: sweet- some front to back staging is kicking in.. but, best of all- echo and decay is coming in strong (yes, these correlate totally)

At this point I would be dissapointed if no further front to back staging happened. To have so much height in the stage, and exceptional detail and imaging, to be without a nice stage depth would be a big achilles heel for these to be anyones 'endgame'.
I have ZERO doubt (pun perhaps?) that more than thirty hours IS needed for these to net their ultimate sound quality and designed for performance.. I have had a few pieces of headgear settle reasonably around the fifty hour mark, but they were not comlex multidriver parts (that all are playing on their own 'break in' timetables.

Anyone with a set of these with 1000 hours on them would find, in my not so humble opinion (in this case) a coherency and smotthness in the frequency plot that would be very different to those posted.. (15dB drops in 10-15khz range is not something to design for... )(unless you know the parts and what happens after some break in)

break in on 5.6mm dynamic drivers takes LONG time. Planars of such a small size is something I have zero experience with, but having broken in a couple of sets of Audeze and some Hifiman Sundara's; I'd believe that the region to kick in the most after a little break in, and 'most usefully' after a LOT OF BREAK IN, will be the Planar driver..
BAsically: three different techs all break in differently/differing times

decay time inside of 3 hours/10 hours 30 hours has shown that these are no where near being 'done'

Observations regarding the Zero1 based on the instore demo set revealed that four different amp qualities (And 'technologies') delivered wildly varying bass definition and texture.. (QP1R DAP is 'current mode' amplification, whereas a Sony PHA3 is 'class A' and of a decent quality near equal to decent desktop stuff, the iFi Diablo and the direct outputs from a FiiO M11+ and AK SE700 all being middle grounds to those extremes...)

Some reviewers have noted that these scale well with better equipment.. I wholeheartedly agree.. but I'd take the statements further (the internet reviewers qualifying that statement listed 'budget' equipment as 'upgrades' and that set a ceiling in my mind as to the tiers of equipment that these would make use of... (I figured their might be some wall of quality limited by the 'very complex'(manufacturers press notes) electronic crossover.

What is objectively confirmable is a couple of things:
Astell and Kern previous coalaborations with Jerry Harvey and Campfire was to 'lift their technologies/research and design with regards to multidriver and multi technology IEMs. (the first line of text on the product box explicitly states this)
A very knowledgeable engineer of seventeen years expereince with Knowles brought a lot of 'know how' to the implementation of the Armatures, and the customised design in this part is no doubt unique.

Clearly these were a gift to consumers to put together such an incredible part, properly, leveraging A&K market strength, ability to 'take a loss' (or 'less profit') if needed to launch a product line and gain reputation..
These are definitely a market 'litmus test'; and I would hazard are a great marriage of tech evolution/knowledge and ultimately 'achievement' in bringing something outstanding to very dense IEM market space.
With so many parts vying for our attention- many consumers do the internet 'research' thing... generally meaning a few early adopters can shape the wave of enthusiam for the product..

These 'budget' IEMs have detail akin to my 4x the retail pricepoint Ultrasone Edition 5s -
Basically anything but my best OVER EARS are slaughtered by their performance.S
ure they don't have the low bass rumble of the Sony MDR Z7, nor the front to back staging* (*yet(?!))

In their unbroken in state they are addictive to listen to.. the amount of clear lyrics and nuanced details in a range of recordings has proven their current worth (even if their sound prfile changed not one iota in the future)
I'd definately want these on my 'short list'/audition list, but then would be at the mercy of comparing a lightly broken in set that might not be representative of their ename sound.
not an issue so much if doing apples to apples comparisons, ie looking at other IEMs using three driver technologies with the same configuration (some use the planar in the mids with BAs doing the highs, where as there are other IEMS with a similar configuration to these (BAs for mids and planar for highs)

As a person who understands the value of good crossovers in speaker design (for the longest time I used AR LSTs as my mains (speakers) whilst rotating through some world class 'best' ancillory equipment), I have come to favour simplet two way speaker designs over 'more complex' multidriver designs.. the notion of multidrivers isn't a drawcard for me...
On the day I auditioned these I tried a seven driver BA IEM from a much higher price bracket, and the timing/skewing of info had me rip them out of my ears very quickly; sure I could have acclimatised to them.. but that is not what I want from my hifi rigs.

True I purchased the AK Zero1 as a 'fun IEM' and I do not think they fit this bill at all.. they are absoutely a joy to listen to ANYTHING, and I cannot believe how easily they have pulled apart some of my 'favorite recordings'

Example: I used to think Blues Brothers 2000 was a great reference disc, but these things reveal every cut and mix and background bit of noise. I still enjoy the disc (the last track alone is an all star mix of some of the worlds best blues musicians/artists), and I am not sure the kids' soprano is at the right pitch.. (something that Arrested Developments Mr Wendal and Everyday People had me questioning these IEMS timing.. like a turntable slightly out of time)..
I'd not use these as studio monitors due to their 'all over the place' (graphed) frequency responce, but more so the lack of front to back staging and the horrible 'out of box' decay time..
I would absolutely buy these if the rest of my kit wasn't a V sound curve.

These do sound right in ways that many of the headphones in my house do wrong. a fast panning 'car' driving through the soundscape on these literally gets my head to spin, like a slap to the face.
Visceral sounds when needed,.. everything isolated and not blurred of worse, 'overly etched'.. and vocals sounding like they come from a dedicated valve amp into a dedicated vocal monitor (speaker) correctly placed on a large stage is incredible.
Phase shifts and complex nuances like getting micro or marco dynamics right.. something that a multidriver affair that plots the way the few internet graphs show just doesn't align with the experience of actually listening to these.

As someone who uses a Sunfire Subwoofer- whose claim to fame is 'how small a sub can be whilst delivering such exceptional bass note quality and depth' simply requires A LOT MORE POWER TO ACHIEVE THIS. (3000 watts in case of my 'small sub')

The only achilles heel these things have is 'better quality amplification' nets major audio benefits.
At their launch price I feel many with the cash will have passed over these,.. leaving them paired in many cases with lower tiered electronics than they probably deserve.. They scale exceptionally well with better kit, and, as an example, sound like junk from an iFi Diablo amp output vs the same Diablo (as a DAC) feeding into a Grace m903 amplifier- amp quality really helps these things act controlled and likely deliver the performance they were designed to give

Buy with confidence.
The black AK Zero1 come with a 4.4mm pentaconn connector (balanced cable), the grey ones come with a 3.5mm cable.

If you can find these on sale, even better... I know this info is 'late to the party' but the internet is forever (apparently) and so I have put this up for my quick 'two cents'. (hahaha 'quick', sure!!)

I will update my thoughts on this part over the next few weeks. One of my favorite hifi bargains (a FiiO BTA30 (Pro) is a near essential buy for many too)

Nice write up! Perhaps I need to break in more.. Have the grey for sale for $350... PM me.

And there happens to be Zero2 on the horizon

 

[whitedragem]

tried using a 7Kilogram Burson amplifier.. and 'yes' it delivered even better bass note delivery'..
going back to the Grace m903 almost felt like a step backwards akin to using the iFi Diablo after the Grace m903 ..
(edit: not in the bass, but the m903 became treble rich in a way that the Diablo did.. in my case the m903 sounded nicer for this in a way that the Diablo DID NOT)

the AK Zero1 definately scale with much better equipment.

was fun playing around...

For the record.. perfect pairing with an SE700 (A&K player)
they compliment each others response curves, and the SE700 looked like a serious throwback to building for 'musicality' rather than 'spec sheet'. This marriage is goosebump inducing (with the right media), and made me feel like the first time I heard some Audeze Sine (On Ears) paired with a Chord Hugo.. (some parts just have a synergy that equals 'real music')

big stack or pocket wonder... (great for the road and for the home)
I have always been an 'over ears' headfier for home listening.. Not anymore!

update: the front to back stage is actually placed 'around us'.. depth behind me is awesome!
Very keen to try some gaming and media (movies), the soundstage on these things is looking like a big win for my typical uses!

 

[whitedragem]

Oh 'wow'.

Keeping these buds cooking...
Dire Straits- Private Investigations.. now Knoflers voice has appropraite processor echo.
the crash just prior to six minute mark is easily forward and extended a little further left than the first four hours of listening..
I know most will say it of this song, but it is like 'built for these' (IEMs)

sadly Maroon 5 played on after, generally with 'built for radio' levels of loudness.
My amp was already beyond the 1pm threshhold (volume dial), which didn't lead to a lack of driver control when playing the 'very dynamic' Dire Straits track.
The difference was that the screechyness of unbroken in BAs was in full force.. most wouldn't hear it true, but years of listening to HArmonic Distortion test tracks (why? - why not!), .1% distortion I am senstive to... not that there was any 'ringing' but treble control is off (which is true of most kit I listen to 'unbroken in')..
normally the 80 hour mark wouldn't be anywhere near close to me listening (seriously) to kit.. so , I can forgive an 'overdriven' amp playing compressed LOUD music and not having masterful accomplishment of such.

Prior to Private Investigations I had played some Gomez Liquid Skin (Devil May Ride, a favourite test track for decades now),.. It nailed this song. Bass line on song start was not quite 'tight' but definately there and very physical.. and showed me that these IEMs place sounds correctly,.. like valve amps that recreate actual point sources... you could hear the bass line, and even when the song got complex, it lost 'very little' (impressive).
again this was an amp set to louder than I would usually use it.. (with IEM volume louder than I enjoy for casual use)

These IEMs are not designed for super low level or super high level listening... their responce curve goes out of whack (at the moment)..
both of those extremes are beyond any listening I would do... (on any IEM) and the loud passages I was testing was against some Ultrasone Edition 5 that use 's-logic' (an engineered tech) that resolves the music across the entire pinnae and generally allows music twice as loud to be non fatiguing.
That level of music direct into my canal. 'Uncomfortable'.. so when unbroken in drivers linger on a frequency too long/decay not 'quick enough' I notice it. At this point it is a small part of the frequency bandwidth that is 'music' that reveals this.

compressed music, overdriven, into sensitive ears, and the wee screechyness experienced is actually nice. (I could listen to this... but would prefer to use discs that simply sound cleaner on the same kit)

Todays first tracks were from Supertramps It was the Best of Times (It was the worst of times)... a live Supertramp album that followed up 97s' "some Things Never Change". This is my least listened to Supertramp album as it is a horrible live recording, (Live In Paris, in Dolby Digital, is my preference if only for the song selection, sure).. but the musicality of the band is still worthwhile.. (whilst I went five years without spinning this disc 'at one point', it was enjoyable on these 'lightly broken in' IEMs.

I put it on to detect stage depth.
Hence "Wow" as opening word for this post.
Hearing how huge the arena is, hearing the crowd echo through the space.. hearing the fans clap the band on.. was all appropriately 'out there' and then when hearing electric guitars own physical stage space (echoing back from above) was incredible.
Every jeer and cat call from the crowd..
Listen to Me Please (from 97s STNC album) has Rick Davies go 'high register' singing nearly at the end of the song. That was 'out' to my ears vs my previous experiences.. (I look forward to coming back to that in a weeks time)
Goodbye Stranger really gets the crowd involved and made me realise that if the sound of these changed 'no more' I'd still be happy.

A little unusal though is that I have only owned a few products that get 'a little worse' before they settle (those same edition 5s were UNLISTENABLE from hours 500-800 of break in, something Tyll (innerfidelity) is famously on video for regarding some ED8 or Ed10 Ultrasones) (small metal foil drivers take a long time to 'settle')..
The Planar part in these needs taming (I found Sundaras' unlistenable out of the box, but Hifiman wanted 300 hours on them, and so I obliged).. straight from box, Cymbal hits are beautiful, and still are.. but other areas need some serious taming..
fortunately the low level info is coming in well and so stage depth is 'a thing'.

I post this mostly to correct my previous post suggesting they stage 'behind me' really well.. I was using a Topping DAC that is horrible for front to back staging (worst DAC I have ever heard even though, by the spec sheet it is 'the best in the world' or some such BS).. clearly the DAC I know isn't musically tuned (spec sheet warfare 100%) has proven itself consistent on every speaker headphone and amp it has ever been hooked up to.

Of all the DACs ever listened to (by me) it is the ONLY DAC that has no 'front staging'. It is like a ruler straight through the head.. hence when these IEMs that give every instrument airspace (grinning like an idiot I am due to this being beyond expectations three days ago) places large dynamic swings on single point sounds.. some of them sounded 'too far forward' (literally 'behind me').

removed topping DAC= fixed!

The isolation these IEms give everything, whilst layering sounds in front and behind each other reveals how well a tech marriage has been pulled off here.
If you are reading this it is probably because you have a set in your sights.. Just Do IT!

The internet never picked these up and promoted them.. (for logical reasons)
Just like their successors about to start retailing.. they are cheap vs the associated equipment that will give them their best .. (5 Ohm AK Zero2 will need certain amp pairings to sound 'best'...)

Do not be afraid of the 5.6mm bass driver... JIm Keltner has test track on TDK sampler disc (given away in the 90s) which informs how to listen to tone and texture and 'drums' in general.
These do it all and my mind wouldn't believe this if I hadn't experienced it for myself.. but is a large part of why 'good amps' scale these babies waaaaay up the ladder.

with proper driver control they show that these were a pretty masterful 'first' (inhouse) attempt.
I'd say they launched cheap to garner interest, and then were associated with low tier sound, and passed over by people with rigs to do them justice.
The tier they live in is filled with all sorts of exciting premises and tech monstrocities that may not make these stand out when doing an A/B compare.. but - if 80 hours has shown me much... these will perform way better for you at home than any stressed 'quick listen' might suggest.

I love the integration.. This is like proper home theatre speakers from a processor and poweramps.. you know when sounds become clearer (at high volume) simply due to having 'so many drivers and 'point sources' handle the playback...

vocal delivery (and instruments) when live rock concerts, at volume, are smashing it out, is just better than I expected for this pricepoint (admittedly I do have limited 'good' IEM expereinces).. but VS great speakers and headphones.. Florence playing Rabbit Heart (Raise it Up) this morning was truly an incredible listen. (musical and natural.. and no idea there is four drivers here.. just clarity and positional focus and proper dynamic power through the whole spectrum.. (although recall voices, slightly higher in pitch, seemed borderline screechy, but I was at 2am on the amp, and louder than I'd ever actually listen unless on the Edition 5s).

Keeping an eye on their evolution.. 150 hours should be the next station on this journey...
I expect 600 hours to be the present trajectory based on overt changes and the speed they have happened so far.
Again this things can be subtle to some.. and many might not even notice much happening.
At 80 hours they are vastly better in some ways than out of box, but screechy in ways they were not.. like other headwear I have seen this happen with.. just hve to 'keep on truckin'.
I have Zero (pun) doubt they will settle beautifully.. to much R&D to get to this point and 'not be aware' that a super tiny planar dirver might need some serious breakin time (and was no doubt tuned appropriately)
For second hand buyers I bet many first owners will have passed these on prior to 100 hours.. (bargain- go grab!!)

 

[XERO1]

The AK ZERO2 has been announced. MSRP is $1050.

Quad-brid with 5Ω@1kHz impedance. Some DAPs may have difficulty driving this.

https://www.astellnkern.com/product/product_detail.jsp?productNo=144

 

[whitedragem]

The AK ZERO2 has been announced. MSRP is $1050.

Quad-brid with 5Ω@1kHz impedance. Some DAPs may have difficulty driving this.

https://www.astellnkern.com/product/product_detail.jsp?productNo=144

indeed 'some amps' will have have issue with that 5 ohm target.. (bass driver control being 'arrrrgh')
listening to the 'version 1' product on all my kit.. I wouldn't be able to do that with the replacements.
I do not own DAPs good enough to be front end all the time... (on public transport doesn't bother me at all), and if I had IEMs at this price point I would WANT to use them a lot.. (once hearing something this good, going to 'home stereo' kit, south of a 10k$ US budget would be a downgrade in many aspects of the sound)..

Is why I would rather put another set of AJ Zero1s in a drawer in case my first ever need replacing.
As someone who owns 'decent' two channel.. (mostly runs pre and powers, and room tunes etc), the audio from the AK Zero1 has been a lifechainging experience.
I honestly could not afford overears that touch this level of audio.

I do believe that the new ones do a better job of establishing what tier AK audio team are selling.
The Zero 1, based on audio beyond the '100 hour mark', are simply incredible value.

My endgame IEM.
(some details are slightly masked vs what I imagine three times the price might net... I said to the missus I want to compare these against top of the tree bits to see what I am actually missing out on (with these).. It would have to be akin to having the musicians in my ear canal ("hooking the G". to quote Lois/'family guy') or else not worth it.. (to me).

I haven't been caught out in any genres yet.. but then haven't listened to anything orchestral since the first four hours.. (was flat and without decay at that point)
By hour 100 these have 'no bugbears' and are the best audio I have ever heard. (and not in a fun or fatiguing way where the next product is 'better' simply due to being a relief to 'get away' from something designed to catch your attention etc..)

AK Zero2 will probably punch above their pricepoint (if same integration as these), but only on well selected matching ancillories. (check reviews associated equipment when deciding 'validity' of the results)

 

[whitedragem]

Quad-brid with 5Ω@1kHz impedance

Quad-brid? I thought it was still a" three technologies used" ('tri-brid'), with double the armatures, double sized bass/'dynamic' driver, (double complexity crossover?), and double the cables in box...

 

[XERO1]

Quad-brid? I thought it was still a" three technologies used" ('tri-brid'), with double the armatures, double sized bass/'dynamic' driver, (double complexity crossover?), and double the cables in box...

From AK ZERO2 page:

Single 10-mm Dynamic Driver with Piezoelectric Transducer- [Low & Super High]

The Deepest Bass and Clear Treble Sound

Various types of carefully designed drivers create rich, Hi-Fi sounds. The 10-mm dynamic driver used in the AK ZERO2 is meticulously manufactured using a fully automated process. This allows the driver to recreate rich and deep low frequencies.
An additional piezoelectric transducer works in tandem with the dynamic driver, serving as a super tweeter that asserts its presence in the super-high frequency range that many IEMs struggle to recreate.
_______________________________

A&K is claiming that the dynamic driver they are using is some kind of 2-in-1 design, but whether it actually uses two distinct driver types or is just A&K getting creative with their marketing is unknown at this point.

 

[whitedragem]

A&K is claiming that the dynamic driver they are using is some kind of 2-in-1 design, but whether it actually uses two distinct driver types or is just A&K getting creative with their marketing is unknown at this point.

Brilliant; thankyou for confirming.

This seems the present audio trend... (a few companies are doing 'stuff like this')..
In terms of 'point source' for audio and 'time alignment' it no doubt does wonders, and has advantages for enclosure size and weight (and potential comfort from finding balance in the design for 'weight distribution') ..

I'd say this is 'something'.
Super tweeters do PRESENCE.

Some Bowers and Wilkins DM (domestic monitor) 1s' (from the sixties I believe) have supertweeters, and even playing back stuff not from Vinyl, offered 'something special' regarding audio playback.
It did require some equipment pairings to make use of,.. and oddly when playing back HDCD recordings I could hear an inverse of the music in a low (volume) level playing in the super high frequency range... not that we 'hear' super high frequencies.. but my anecdotal story hear suggests we do..
I believe we do, or 'some people do', but not in obvious ways and it certainly does fill in and crete presence (although that may be second harmonic dependant or some such..); there isn't a LOT of science on this cause science requires 100% repeatable results and humans all have different ear training etc (eg a conductor has phenominal ears, generally, associated with their 'line of work'. My conductor friends can determine polarity on my DAC in a heartbeat.. "can't you hear the attack on the violins" (nope! but forever scarred that my decades of audio training still had 'huge gaps' in knowledge and 'training'))..

The BASS cavity is the only one that would allow the super tweeter range to propogate properly I'd imagine.. so a bonus with regards to design implementation no doubt.

maybe we should move discussion of the AK Zero2 to the appropriate thread, assuming one is up?

regarding the tuning on the AK Zero1;
after 100 hours break in a few things happened..
the sibilance that started to occur around the 80 hour mark too a back step (yay), but now are extremely treble rich in a way they were not two days ago.. (and it isn't just me chaning tips and DACs ;'tested'!)
I can literally see 'by ear' the different drivers kicking in as the breakin happens.
This is one of only a few parts I have ever heard that 'nose dive' in sound quality (to my appreciation) prior to sorting themselves out.. (foil driver Ultrasones significantly so)..

The audio around hour 80 becoming mostly sorted around hour 100 gave me cause to rethink the schedule.. (was thinking 'beautiful' these may be 200 hours or even sub 200 hour burners..), but with what is happening at the moment.. I feel some of the drivers still need to settle. (three different technologies, yes?

Rick Davies in 'live' Listen to me Please', is now in the right register towards the song end.
Kate Bush and Florence sounding more stable when they go through their 'range' too...

the new high frequency rise is harsh on a few recordings though, and my guess is the Planar is being stubborn to 'come good'.. (low level live music and applause tracks as part of the burn in cycle, cycling volume levels a lot too)

The traits of these IEMS is fascinating at the moment.
The frequency spectrum playback at low volume and high volume being vastly different to their mid volume (what I typically listen to across ALL my gear).. the mid (volume) appears practically flatline with regards to playback.. and is a great experience.. but there is certainly some 'presence' information that needs to sort itself out.

Directions In Groove (band, a.k.a. D.I.G.)Two Way Dreamtime (track) is about the only song that keeps me going 'somethings wrong', but to be fair this was a local Canberra band and I got into them as a teenager, and probably isn't the best recording.. (but I have met Terapai- the Didgeridoo player, who toured with Billy Fields (Bad Habits/You Were in Love with Me) when 'doing Australia')
That track has ambience and I am familiar with it stretching out into the corners of the room.
It is simultaneously missing some 'darkness' whilst also being intimate and 'staging weird'. I think it is the unsettled planar killing it presently.

Hearing live 'the Prodigy' , Firestarter (an atrocious recording) ("Their Law" album) is crazy.. you can hear how large the stadium is.. (must have been one of those events that a tonne of bands play at and the audience is massive beyond belief..), but the setup makes you feel like you are behind the stage looking out at it all...

Getting back to 'live' Supertramp; "School" has some recorded sounds of 'children playing' and this being in the mix when 'on stage' and having the present 'brilliance' of the unbroken in parts/planar.. is one of the 'tells' that things are still settling.

Vs the frequency plots that the internet has on these IEMs, female vocals are 'very settled' (already), and certainly much smoother than 'out of box'/pre 80 hours runtime.

I have no idea with regards to a 'mini' planar breakin, but given how little audio information is in the region it is playing back, I expect it to take quite awhile to come great..

They are certainly 'requires breakin' IEMs.. I doubt many users played them beyond 100 hours if they don't believe in such things..
for me.. hours 80-120 was the hump to get over.
Right now, I like them almost less than 'out of box' (when at high or low volume), but the decay and hence stage setup of all recordings is 400% on what they do cold/new.

harp on Florence is to die for.
Phil Collins studio tracks are exemplary.. these things do bass notes on a range of recordings much better than 5.6mm driver has any right to do.
My guess is it is a tricky driver material, and likely 'very firm', and hence will enjoy some good hours burn in.
The multinote bass delivery and physical presense the AK Zero1 render is beyond what I would expect.
the texture of bass notes, the tracking through air space..
Phil might be singing "you can't hurry love", and that is these things 'in a nutshell'..

If the version 2s are more mature, and in any way an improvement.. (as the literature and tech developments would indicate), they are likely 'pretty special'. (/audition worthy, but make sure the team at your local head-fi store has had them 'warmed up' some..)

 

[whitedragem]

A few low resolution images DO NOT do these extremely high resolution monitors justice!

Sitting here listening to burn in tracks, simply because anything I throw at them is addictive.. You know when you mean to only put a track on but listen to the whole album- With these works of art (musical playback) I find it easy to listen to repeating albums..

Not one genre is caught out. Their staging goes FOREVER!

Inches of Darkness (TJ Eckleberg) - a long time favorite track for 'staging' information is exemplary.
Equal to the best rendition I have ever heard (a mates studio monitor setup playing back from a nice R2R DAC, with room tuning and 'sorted' system setup)- the opening 'drumming' resolves a full 50ft back in the stage.. but better than typical playbacks, the height of the drummer is seperate. His 'cough' above the surface drummed on.

Private Investigations (Dire Straits) - same thing.. (amazing sound stage setup) the 'crash' at the six minute mark now has air around it. (dark and decay removes the speakers from setup - 'you are there') the extension of the stage with north of 250 hours on the drivers has shown that the break in isn't too bad a wait time,.. but ABSOLUTELY NEEDED.

These IEMs are 3x the product they were 'straight from box'

I could list a 'lot more';

Whilst this song has never been an audio test track for me (it was an Apple Music find.. ) the original song is a very powerful track,.. this version holds strong emotion content, sure,.. but the voices, layering and positions makes a person feel like they are hovering in Sennheiser HD800 territory (for detail and placement).. (I am afraid to run Blue Man Groups' "Your Attention Please" since they completed mandatory burning in- something that at 180 hours wasn't done.. but around 220 hours started to feel like a 'complete WELL INTEGRATED package- with how they perform now, I have zero care for further burn in delay.. these are THE BEST headphone sound I have ever heard in a range of metrics)


Dynamite = very 'studio' perfection; Sony had all sorts of '20 bit mastering type strategies.. ie SBM (Super Bit Mapping), I never checked the liner notes on this album, but given earlier Jamiroquai releases all proved exceptional, this album has always proven 'very high quality'.
Talullah has these 'low level' bell sounds that are incredible to have resolve. (shows the detail retrieval capability of these insanely GREAT IEMs).


some serious listening tests jumping between a couple of DAPs to check amplifier pairing and playback quality...

An incredible aspect of the AK Zero1 sound was revealed to me..

The Questyle is a very high quality digital transport (for any who believe such things matter,.. just don't let the science thread zealots hear your thoughts on the topic!)
The QP1R, whilst being a great little music player (and uses Questyles' Current Mode Amplification), the differences when resolving a fairly simple track or three (Enigma "Dusted Variations" (not actually Enigma/M.C. Curly if I have read correctly))..

on the Questyle QP1R - whilst the bass notes and soundstage and other aspects of the song played beautifully,.. it had nothing to compete against the Piano being played back via a 'tuned for music' Astell and Kern DAP (below)

The A&K SE700 owns this track.
The difference between the playbacks was so substantial in the piano keys in particular.. the SE700+Zero1 combination just punches so far beyond what I would expect any system to be able to render.
This combination reveals an aspect of just how well the AK Zero1 scale with equipment pairings.
On the SE700, if a person cared for their piano notes, would equal a 'must buy' (vs the same IEMs on the QP1R, an auditioner might miss the glory that these 'buds are capable of)

In fairness the SE700 is a litmus test product to see if consumers care for audio>'spec sheets'. - it was a part tuned for music and the results speak for themselves.
The AK Zero1 are some of the best monitoring sound quality a human can find. (after a couple of hundred hours break in)

FiiO M11+ (offscreen source)=>Diablo (DAC)=>Grace m903 (amp)=> AK Zero1 (endgame IEMs)

I couldn't place a review up as it seems no one has done so yet.. (or I had the wrong location on headfi).
So- updated thoughts here..

Money where my mouth is - I bought a second set. (irrelevant of pricepoint these things sound better than some of the best audio kit the planet has ever made- they certainly need some 'awake' time to get the drivers singing..
Hour 80-120 was some sibilance in vocals
Around hour 220 led to the disappearance of about a 3% distortoin on the armatures (vocals) irrelevant to volume. (vol 41-71 in low gain on the SE700 revealed it 'very clearly' (other equipment too..)) It wasn't distortion from volume,.. but just a need for the drivers to find their ultimate 'full' stride.

Weaknesses: need at least 250 hours burn in (usual for many headphones really)
Low volume levels and really high volume levels (just outside my normal range of listening) the frequency response gets out of 'flatline perfection' (not ideal for users who like to rock out above 85dB) (low level 'bass boost' is argualbly a good thing, like old Yamaha stereo amplifiers that had a contiunously variable loudness adjustment.. (at low levels a little extra bass is a good thing))
Included tips didn't fit my ears or give me comfort (I lifted some dual flange tips from some Cardas IEMs and 'voila'/comfort, Your Mileage May Vary)
Strengths:way to cheap for this much sound (I found double price point part unlistenable vs these, they hold their own against the Ultrasone Edition 5 for detail and staging (and soundquality!!) OUTSTANDING)
With the right tips, extremely comfortable.. I can listen to albums on repeat an not care how much time has passed.
Partner caught me sleeping and waking listening to Enigma (first album) over and over again (a very good sign to spend three hour sessions and 'still not have enough time')
soundstage.. (incredible) front to back better than any IEM I have tried, and besting most over ears used (by me) as well. (which is a lot, especially as I buy headphones for 'soundstage' first)
height staging (probably the best I have experienced)
layering and detail.. I have picked up so many extra moments in songs I am exceptionally familiar with.

These are not just 'keepers- these are 'hunt them down' (And pair them with an SE700 if only to hear how music should sound..
The second set I nabbed are in black, and have the balanced cable. Ideally, next week I will have these running off an AudioGD R28 in balanced mode.

Thankyou Astell&Kern for 'lifting' the best IEM makers knowledge (coallaborations MY FOOT!), and making these available for 'cheap'.
They just keep scaing with better kit.
I re-rigged my best amp off my best DAC (den setup) for my portable buds' (feels wrong).. and whilst I liked using Sony MDR-Z7 (or AKG K612Pro) (both super large 'over ears') for gaming.. I must admit these are a legitimate contenders to take over 100% gaming duty.. (with advantage of not needing inline amps ie makes VR gaming one less cable for me/'safer') (I don't consider that a plus, cause most players are not 'audio snobs' and are willing to use controllers and headsets included 3.5mm headphone sockets.)

exceptional for typical listening levels,
proper bass note delivery, texture and tonality, and multinote bass equal to the best home rigs.. with a coherency and smoothness to the integration that no area of the sound spectrum feels over or underdone.. These do not playback like the plots I have seen.. (volume dependant based on my experience).. of course they are so clean in sound that turning them up to unhealthy levels is possibly a desire.
Turn them down and listen to the whole stage play out.. At listening levels we should stick with these are unbeatable by price point and technology given.

***** (five / five stars)

 

[whitedragem]

The AK ZERO2 has been announced. MSRP is $1050.

Quad-brid with 5Ω@1kHz impedance. Some DAPs may have difficulty driving this.

https://www.astellnkern.com/product/product_detail.jsp?productNo=144

I feel, for me, the usable "perfection" volume range on the AK Zero1 is in the ballpark of 65dB-80dB ;a little beyond where I like to listen and I notice the drivers lose some volume cohesion, or 'aspects of flatline'.

I have a strong feeling these (AK Zero2) are built to take that pure audio perfection and allow listeners to take them to higher volume range whilst maintaining clinical sound quality. -it would be the only real/actual (potential) weakness of the Zero1 design- for users who listen louder than I ever would...

My favorite "Pro", something many have in their daily drivers is actually a super simple 'quality of life' changeup..
The AK Zero1 has such addictive sound properties, that I take them to bed (actually built a nicer bedside setup to 'do them justice' as they scale so well to best my best kit).. where the Cardas IEMs, round in form (a single Dynamic Driver design), I need some light (at bedtime) to know left from right..
The AK Zero1 design always has me smile a bit, in the dark, as they are like 'little arrows' pointing front facing.
I can get up in the wee hours and return to bed (returning to IEM listening heaven) without the need of a phone or taking the DAP out of a cradle/"cables" (or twisting body to get my head near the DAP screen as a light source to sort my left from my right).

The AK Zero2 design that likely offers more volume range whilst holding its true performance capability is the design target that needed hitting.. (for many, no doubt).

If the AK Zero1 went louder whilst holding their exceptional sound tuning I would have hurt my ears by now.
I find it hard to tell exactly where the volume is due to how clean they prove to be (like top tier, mega heavy (home stereo kit) Class A amplifiers that are so pristine you burn out tweeters before realising 'ears are going to ring for a couple of days').
Up, Up, Up..
or as Astell seem to be doing-
"Onwards, and Upwards" (The Last Battle, C.S. Lewis)

 

[singingbee]

hi! when can we purchase the zero 2?

 

[gto88]

Zero2 surely is an interesting configuration, and quite a step up from zero1 per spec.
I wonder why AK‘s IEMs get more attentions by press/ad than in hifi world, no matter what they have to offer.
but this zero2 might do better?

 

[Maximiliano Campo]

The AK Zero 2 has been out for a few months, but theres no reviews anywhere? Very strange, I would have thought there would have been a few reviews by now.

Has no one heard them?

 

[Maximiliano Campo]

Zero2 surely is an interesting configuration, and quite a step up from zero1 per spec.
I wonder why AK‘s IEMs get more attentions by press/ad than in hifi world, no matter what they have to offer.
but this zero2 might do better?

Very strange there’s no reviews anywhere for it despite being released for a few months.

 

[gto88]

Yeah, I have been searching too, but see none so far.