This mini review is actually a small part of a larger review/thread covering all of the T-Peos Altone series. Here is a link to the review:
 
http://www.head-fi.org/t/774084/t-peos-altone-series-thread#post_11751591
 
T-Peos Altone 350 ($379 on CTC Audio’s website)
http://www.ctcaudio.com/collections/t-peos/products/t-peos-altone-350-3-way-hybrid-earphones

 
The 350 carries a similar package to the 250, with titanium housings and the same cable options. You get two cables (one with a single button microphone in black and a red cable with not mic/remote). The 350 takes things a step further with more tips to choose from and a high qualtiy leather case to hold everything.
 
The 350 takes a road less traveled in the IEM world. If you are sensitive to treble, STAY AWAY! Without an EQ adjustment, the Altone 350 are flat out sibilant in my opinion. Your mileage may vary, just be warned that these are not for those sensitive to forward treble response.
 
The Altone 350 is a triple hybrid design with a 10mm HPS driver and two Knowles armature drivers playing the high frequencies. They really do have a dynamic tuning that provide a level of timbre that the others don’t (with the exception of the 250 being relatively close). Everything plays with fantastic resolution and clarity, but the tuning is not neutral or natural to my ears. There is a boost in the mid bass range. While it doesn’t bleed or overshadow the sound like the Altone 250, it is very forward and sounds unnatural to me. There is also the previously mentioned Treble boost that jumps out in front of the rest of the mix.
 
I will go as far as say that these are different from the pack and some will really like them for what they are. What they are not is neutral or natural sounding. If you want a very aggressive tuning with enhanced dynamics these are right up your alley. Their dynamic tuning and resolution will impress those who are looking for this type of sound.

INTRODUCTION

My first experience with T-Peos was almost a year ago, when I had the chance to review their (at the time) new budget based triple hybrid IEM – the Altone 200.  The Altone 200 set a new benchmark for me in sonics – especially at the introductory price (at the time) of USD 125.00 – an incredible value.  In fact I was so impressed that I actually purchased the Altones from T-Peos (although I could have kept them as a review pair).
 
For anyone who hasn’t heard of T-Peos, the parent company SWP Shinwoo (http://swpshinwoo.com/) is a Korean electronics company founded in 1986 who started developing earphones in 2012, changed their company name to T-Peos in 2013, and at the same time launched their first 3 way hybrid IEMs.  Their focus is on quality (reading their website is impressive), and it definitely showed in the T-Peos Altone 200. The commitment to build quality continues with the Altone 350.
 
DISCLAIMER
 
I was provided the Altone 350 as part of a tour organised by CTC Audio through CTC Head-Fi Sponsor Empj and facilitated by veteran Head-Fier [b]svyr[/b].  The tour unit will continue back to Australia at the completion of this review.  I am in no way affiliated with T-Peos, or CTC Audio - and this review is my honest opinion of the Altone 350.  I would like to thank (again) svyr and Empj for making this opportunity available.
 
I’ve now spent a 7 days with the Altone 350, and have around 20-25 hours listening time with them. Normally I would like to take a minimum of 10-14 days before I write a review/impression – but owing to tour restrictions, 1 week is the maximum time I could dedicate to the review.  I do feel I have a good idea of the strengths and weaknesses of the Altone 350 in that time though.
 
PREAMBLE - 'ABOUT ME'.   (or a base-line for interpreting my thoughts and bias)
 
I'm a 48 year old music lover.  I don't say audiophile – I just love my music.  Over the last couple of years, I have slowly changed from cheaper listening set-ups to my current set-up.  I vary my listening from portables (Fiio X5, X3ii, X1 and iPhone 5S) to my desk-top's set-up (PC > USB > iFi iDSD).  I also use a portable set-up at work – either X5/X3ii > HP, or PC > E17K > HP.  My main full sized headphones at the time of writing are the Beyer T1 and Sennheiser HD600.  Most of my portable listening is done with IEMs - and up till now it has mainly been with the Fidue A83, Dunu Titan, Trinity Delta, and DUNU DN-2000J. A full list of the gear I have owned (past and present is listed in my Head-Fi profile).
 
I have very eclectic music tastes listening to a variety from classical/opera and jazz, to grunge and general rock.   I listen to a lot of blues, jazz, folk music, classic rock, indie and alternative rock.  I am particularly fond of female vocals.  I generally tend toward cans that are relatively neutral/balanced, but I do have a fondness for clarity, and suspect I might have slight ‘treble-head’ preferences.  I am not treble sensitive (at all), and in the past have really enjoyed headphones like the K701, SR325i, and of course the T1 and DT880.
 
I have extensively tested myself (abx) and I find aac256 or higher to be completely transparent.  I do use exclusively redbook 16/44.1 if space is not an issue.  All of my music is legally purchased (mostly CD – the rest FLAC purchased on-line).
 
I tend to be sceptical about audiophile ‘claims’, don’t generally believe in burn-in, have never heard a difference with different cables, and would rather test myself blind on perceived differences.  I am not a ‘golden eared listener’.  I suffer from mild tinnitus, and at 48, my hearing is less than perfect.
 
I’ve used the Altone 350  from a variety of sources, but for this review, I’ve mainly used it with the iDSD, X1+E11K combo, and straight from the headphone-out socket of my Fiio X3ii and also my iPhone 5S.  Although I have tested them with an amplifier, I do not think they benefit from additional amplification.  In the time I have spent with the Altone 350, I have noticed no change in the overall sonic presentation.  I am not worried about burn-in for the purposes of this review as they are a tour unit and have already clocked up at least a 100+ hours during the period of the tour.
 
This is a purely subjective review - my gear, my ears, and my experience.  Please take it all with a grain of salt - especially if it does not match your own experience.

THE REVIEW

PACKAGING AND ACCESSORIES          
 
The Altone 350 arrived in a retail box, in two tone grey and reddish orange. The box is reasonably smart looking with a picture of the Altone 350 on the front, and a list of specifications and accessories on the rear.
 
 
Opening the outer packaging reveals a black inner box with a bright yellow windowed tray cover over a moulded foam tray which snugly houses the Altone 350s.  Lifting this foam tray then reveals a second clear plastic tray which houses the accessories.
 
 

The accessories are generous and well thought out, and include:

1. 3 pairs of hybrid tips (two tone)
2. 3 pairs of standard silicone tips
3. 3 pairs of dual flange tips
4. 1 pair of genuine Comply Tx200 medium tips
5. 2 detachable cables – one with mic, and one without
6. 1 x 3.5-6.3 mm jack adaptor
7. One shirt clip
8. One pair of ear guides
9. One warranty card (printed in Korean only)
10. One zipped leather carry case

 
 

The quality of the accessories is very good – and especially so the case which does appear to be leather with a good quality zip and 2 compartments (although the divider does not actually go all the way to the bottom.
There is a good variety of tips to suit most ears, and I like the inclusion of the short dual flanges as an option.
 
 

The shirt clip is the mechanical type, very well engineered, and although reasonably large – does it’s job well. The ear hooks are the generic rubber type with a split to insert the cable, and as you’ll see later in the review, quickly became the most essential accessory in the entire package for me.
 
TECHNICAL SPECIFICATIONS
 
(From T-Peos)
 
FREQUENCY GRAPH
 
There are some graphs out there of the Altone 350 already – but as I wanted to compare them directly to my Altone 200 and DUNU DN-2000J, I decided to measure them myself.  It takes a little more work – but gives me a better baseline for understanding what I’m hearing.
 
To do this, I used a calibrated SPL meter (not an iPhone app – proper meter), measured using the C weighting, and then translated to adjusted dB levels (ie what we would actually perceive).  This is done by set formula, and I would like to shout out to @twj321 (for providing the spreadsheet and formulae) and @DJScope (for helping me format the graphs). I used a louder than normal listening level and set tones – so I could measure accurately and be above the noise floor.  All readings were checked twice.
 
So here are the measurements for the Altone 350 (after conversion), and below is the graph. A graph comparing the Altone 350 to the 200 and Dunu DN-2000J is posted later in the review.
 
 

 
What I’m actually hearing is a very a clear mid-range, but without excessive treble sparkle, and a very prominent low end.  Treble response is quite well managed, but there are signs of a sibilant peak which very occasionally shows itself with some vocals.
 
BUILD QUALITY / DESIGN / MICROPHONICS
 
The Altone 350 is in a word – “solid”.  It has a traditional bullet design, with a two piece all titanium shell (with black plastic accents/inserts).  Each shell measures 22mm from base to tip, and has a circumference of 12mm at its widest point.  The nozzle is 5mm long and the lip is a little over 5mm wide. The nozzle itself has a black filter mesh at its end. The shells are relatively smooth, and comfortable to wear.
 
 

The connectors for the Altone 350 are the new DC connectors, and on this unit, they feel both sturdy and snug.  As far as overall durability goes – I like these a lot more as a connector than the mmcx.  There are L and R markings on the shell, and also the plug. The shells are easily identifiable though as the right is red and the left is black. One of the issues of seen with this unit though is that the paintwork (rings) on the IEMs is actually coming off. Not the best craftsmanship on a flagship earphone. The DC connectors have good relief below the actual plug.
 
 

The cable is a twisted pair on each side going to a larger twisted four below the Y split. The black cable has a single button microphone above the Y split.  This works well with the iPhone (single push play/pause, 2 pushes next track, 3 pushes previous track).  The microphone is relatively clear on this unit, and hangs just above my chin (cable over ear), and about 70mm below it (cable down).  The red cable has no microphone or push button unit. Both Y splits are tubular with good relief.  Sadly the red cable does not have a cinch (huge omission IMHO). Both cables terminate in 3.5mm right angle gold plated jacks – the black with a 4 pole jack, and the red with a traditional 3 pole. Both Jacks have very good strain relief.
 
 

Both cables are IMO a little over engineered, prone to memory (the red kinks really badly) and are pretty microphonics. The black cable seems to be a little more pliable, and I can wear it over ear without any guides.  The red is very unruly, and I have to wear guides to get it to stay.  A simple cinch is all that is needed.
 
 

FIT / COMFORT / ISOLATION
 
I have one ear canal slightly different to the other one (my right is very slightly smaller) - so I tend to find that usually single silicon flanges don't fit overly well.  Rather than trying the included tips (remembering it is a loaner unit), I instead went to my faithful Sony Isolation tips (perfect fit for me).  There was no driver flex and a really good seal.
 
Spin-fits, also fit well, as did most of the various tips I tried – including spiral dots, Ostry tips and Complys (T400s actually fit pretty well – although T-Peos do include Tx200s). The most consistent, comfortable and best seal was with the Sony Isolations though, so I used these throughout the review.
 
 

Comfort and fit are both pretty good over ear, but the unruliness of the cable does mean that if you’re going to be doing anything physical, you’ll want to fit the ear guides. These work pretty well, but can get frustrating at times.  By far the biggest gripe I have is with the red cable.  A simple cinch is all that is needed (you have one on the Altone200 T-Peos!), so why they omitted this is beyond me.  For an over ear cable wearer – the red cable is just a nightmare without one.
 
Isolation though is very good for a hybrid.  Although I’ve looked for a vent, I can’t find one – and there is no driver flex for me so far.  So if they have managed to avoid a port – well done. It’s not going to isolate as good as Shure, but it is as good as I have had with a hybrid so far.
 
SOUND QUALITY
 
The following is what I hear from the Altone 350.  YMMV – and probably will – as my tastes are likely different to yours (read the preamble I gave earlier for a baseline).  Most of the testing at this point (unless otherwise stated) was done with my Fiio X3ii and iDSD as source, and Sony Isolation tips.
 
Tracks used were across a variety of genres – and can be viewed in this list http://www.head-fi.org/a/brookos-test-tracks.
 
Thoughts on Default Signature
T-Peos house sound for me so far has often been V shaped.  I was hoping to get the same clarity as the Altone200, and maybe a little less quantity but more quality with the bass.  This does not describe the Altone 350.
The Altone 350 does possess an extremely clear mid-range and lower treble, but sadly both mid-bass and sub bass are both a lot more prominent than the Altone 200. The lower treble has been shelved a little, so it isn’t too peaky, and most of the time delivers consistently clear detail – but there is a secondary peak in the 8-10 kHz range which sadly does hit a little sibilance with some of my female artists.
 
So what we end up with is a very clear overall signature – but with quite a boomy bottom end.
 
Overall Detail / Clarity
No issues with detail in my usual go-to tracks (“Gaucho” and “Sultans of Swing”). Cymbals are clean and clear, micro detail is good, nice guitar crunch, and yet vocals are still nicely presented.  My issue is predominantly with bass.  In Sultans, the bass guitar dominates, and after a while the track becomes a little monotonous.
 
Sound-stage & Imaging
The Altone 350, despite its bassier tuning, actually exhibits a reasonable sense of space with Amber Rubarth’s “Tundra” – just bordering on out of head. I’m not sure if this is related to come of the slower decay in the bass notes. The imaging is OK – but the bass does tend to take away from the crystal clear mid-range a little. Directional cues are average, but pretty consistent.
 
McKennitt’s “Dante’s Prayer”was up next, and the overall presentation was pretty good. McKennit’s vocals were maybe just a little too subdued (compared to other more balanced headphones), but piano and cello were very good in tonality and texture, and the whole track blended well. With the applause at the end of this track, there was a slight feeling of connection with the crowd though – so the sense of width and depth is not bad for an IEM.
My last test was with Amanda Marshall’s “Let It Rain” and this presentation was really good. This track does tend to be slightly brighter in presentation, so this suited the Altone 350 well – and the naturally holographic sense of the recording came through wonderfully. This was one of the moments that the Altone 350’s shone during my time with them.
 
Bass Quality and Quantity
By now I knew the Altone 350 could deliver on bass quantity – but how was its overall quality? Mark Lanegan’s “Bleeding Muddy Waters” was interesting, because there was plenty of thump, but to be honest I wasn’t particularly impressed by the overall quality.  Just a lot of mid-bass thump, and no real definition to it.  Mark’s voice had great timbre, and tone though.  Switching to Lorde’s “Royals” took the Altone 350 impressively low and once again that huge impact was very present. When the bass guitar kicked in though, the depth of sub-bass was pretty impressive.  Too much for me though. Ella’s vocals were really clear, but the whole track was just too massively V shaped. Some may enjoy this – I’d want to EQ some bass out.
 
Female Vocals
Like the Altone 200, the Altone 350 has a mid-range which should be just perfect for female vocals, and I was looking forward to testing it. My first test is always Agnes Obel’s “Aventine” and the Altone 350 was really excellent with this track.  Vocals were sweet, clear and effortless, and the bass really performed well when the cello kicked in.  Thoroughly enjoyable.
 
London Grammar was equally as good.  Hannah’s voice had its usual magic, and once again the bass didn’t seem quite so onerous – still cavernous at times, but not obviously overpowering things.  So I played through my usual test tracks, and it was mostly very clean, very clear, and very dynamic. Feist at times was bordering on too much bass (and I don’t usually ever make that comment), but FaTM was very good, and Gabriella Cilmi’s “Safer”, which never fails to move me, had a real connection. Norah was her usual captivating, wonderful self (has that girl ever sounded bad for me on any headphone?), and I think it’s safe to say that I really like the Altone 350 with my female artists.
 
Male Vocals
You’d expect that the Altone 350 with its V shaped signature and combination of clarity and bass impact would really excel with a lot of my rock tracks – yet strangely this is where (at times) the excessive and unbalanced bass just got a little too much.
 
Male vocals were actually rendered pretty well among all my artists, but anything with a lot of bass guitar became slightly monotonous at times.  Some of my older classic rock – 10CC, Jethro Tull and the Eagles sounded brilliant – but whenever I got to anything slightly bass heavier (Alter Bridge, Green Day) I just wanted to grab an EQ and dial down the bottom end.
 
“Immortality” and “Keith Don’t Go” are both acoustic tracks which were presented wonderfully by the Altone 350, and the one thing I noticed with both was that with the absence of bass guitar, the midrange had a chance to really shine.
 
My litmus test is always Pearl Jam. This was pretty good overall, great detail, and plenty of cymbal and snare action.  Eddy’s voice was its usual magic – but again, if I could chop that bass guitar back just a little ……
 
Genre Specific Notes
For Rock and Alt Rock – the Altone 350 was a little hit and miss.  Plenty of dynamics for the most part, and I was impressed time and time again with how clear the mid-range was despite the overpowering bass.  Floyds “Money” was stunningly clear, but sadly the detail was again overshadowed by the bass guitar. PT’s “Trains” was also pretty good – but again that bass – what were T-Peos thinking with this tuning?
 
For Jazz, Blues and Bluegrass, it was a hit and miss affair dependent on the artist.  Portico Quartet was good up to a point, but even the double bass got to me after a while. Yet Miles as a lot better - the combination of trumpet, cymbals and a mellower double bass playing style was quite pleasant. Dust Bowl Children was really good – with the banjo and guitars able to shine (loving that mid-range), but switching to Beth Hart’s “Lifts You Up” (which is recorded a little hot) brought the sibilant peak into play – almost eye watering. Bonamassa in contrast was really good – just not as dynamic as I’ve heard it on an IEM like the 2000J.
 
Rap, Trance and EDM was where I expected the Altone 350 to come into its own, and to be fair, lovers of these genres may well be impressed with the Altone – but again I found them simply too bass heavy. I’d enjoy the first 30 seconds or so of each track, then after a while the bass monotony would kick in and just leave me overloaded.  I really enjoy the EDM I do own, but not with the Altone 350.  The most enjoyable “electronic” track in my rotation ended up being The Flashbulb – and I’m pretty sure this was simply because it’s not an overly bass heavy track.  In fact I could listen to both of TF’s albums all the way through and have a thoroughly enjoyable time.
 
Pop and Indie fared a lot better but still a bit hit and miss for me.  Adele was really good (female vocalist, not bass heavy), but Coldplay’s “Speed of Sound” suffered from monotonous bass line kicking in again by about the 70% stage.  Band of Horses was brilliant - a really dynamic listening experience, but sadly with Wildlight’s “Dawn to Flight” – while Ayla’s vocals had their usual magic – again that lower and mid bass just ended up spoiling things for me.
 
Classical was surprisingly good – on everything I played, and particularly so with Netrebko & Garanca’s duet from Lakme.  Kempffs rendition of Beethoven’s Piano Sonatas was truly breath-taking, as was Zoe Keating’s performance with Cello.
 
AMPLIFICATION REQUIREMENTS
 
The Altone 350 is easily powered straight out of the portable devices I have, and I haven’t experienced any issues with the iPhone 5S, or any of the Fiio Daps. With typical pop/rock songs on the iP5S I’m usually at a volume level of around 35-40%, and on the X3ii around 35/120.  I did try amping with the X1 and E17K, but noticed no obvious signs of improvement.
 
EQUALISATION
 
As you’ve probably noticed, the biggest issue I have with the Altone 350 at this stage is simply too much bass. So with the X3ii I applied a smiley shaped cut (centred around the mid-bass), and then revisited some of the tracks I’d previously had issues with. For my tastes, this is so much better, and so much easier on the ears.
 
COMPARISONS
 
I thought for this section I’d look at two differing points of comparison.  First I’ll look at T-Peos’ own Altone 200 – as it is also a triple hybrid, and should pose a natural question – did T-Peos actually improve with the new release? Secondly, we’ll look at DUNU’s current flagship – the DN-2000J and see where that sits comparatively.
 
I graphed all 3 – using test tones, a calibrated meter, and spreadsheet conversion program. The graph is below, and very much tells its own story
 

 
 
Altone 350 vs Altone 200

Both are triple hybrids.  Both are tuned to have quite a V shaped overall signature with emphasis in the bass and also in the upper mid-range.  Both are very clear IEMs.  Overall build quality would probably go to the 350 – but if we look at what is practical, I’d take the 200 every time.  Sonically the 200 is definitely thinner (comparatively) but next to the 350 seems a lot more cohesive and balanced. I never feel (with the 200) that I need to EQ the bass down. The 200 is also smaller and more comfortable to wear.  Whilst the cable isn’t detachable, it is better behaved (more pliable), and it has a cinch so it makes over ear wear easy. And most importantly it is around ½ the price of the Altone 350, and I personally think it sounds a lot better.
 
Altone 350 vs DUNU DN-2000J

Not everyone will like the 2000J  - it is relatively well balanced, with a brightish tilt to it. Compared to the Altone 350 – the build quality and accessory package is similar, and where it doesn’t have the replaceable cable, it does have a cinch and also innovations like the cable tidy. Sonically the bass quality on the DUNU kills the Altone – it’s not even close.  The DUNU has wonderful speed and texture, where the Altone just has quantity and a monotonous boom. Both are very clear through the mid-range, but I personally don’t find the DUNU quite as peaky in the upper end.  Value wise the DUNU is slightly cheaper – yet sonically (IMO) far superior to the Altone.
 
VALUE
 
The Altone 350 has a RRP of $379 on CTC’s website currently, but it’s a price I really struggle to see any value in.  It’s not overall a bad sounding IEM – and some will probably like its default tuning.  But it’s not the sort of tuning you expect in a flagship – especially when the IEM it is essentially replacing is cheaper, but an arguably better overall proposition.
If you’re a real bass lover, and like a very V shaped signature – this might be to your liking.  But in the $350-$400 range, the Altone 350 just doesn’t scream anything but “meh”.
 

ALTONE 350 – SUMMARY

I was so hoping the Altone 350 was going to be a winner.  I loved the original Altone 200 from T-Peos.  It scored a 4.5 starts from me when I first reviewed it, and I still get it out every now and again when the mood takes me, and I am still wowed by its tonality and overall “package”. At the time it redefined how good a triple hybrid could be for sub $200.
 
Sadly – the Altone 350 is very much a hit and miss proposition for me. While its build is on the whole pretty good, its design has some flaws (over engineered cable, missing cinch, paintwork issues). Sonically it has a gorgeously clear mid-range, enough upper end to convey detail without getting too peaky (most of the time), but it has a flabby, over pronounce bass presence which actually detracts overall from its signature.
 
It’s almost like the designers forgot they were building a flagship – and decided they would tune it for todays bass loving younger generation.  The problem they have is that the same younger generation is unlikely to shell out close to $400 for an IEM when they can get bassier signatures for a lot cheaper.  And the people who typically will par more for a quality IEM are often not the type of consumer who want this much bass. I know I’m stereotyping here (and I shouldn’t), but the Altone 350 really strikes me as being totally confused as to its target market.
 
Sadly – I would not recommend the Altone 350 to anyone I know – unless they really love a lot of bass with a very V shaped signature. There are far better IEMs out there.
 
I struggled with how to grade these – because they aren’t “that bad” sonically, but they aren’t flagship quality either.  For me – they are a 2.5 stars at best – and I know on Head-Fi this shows as a negative – perhaps for the money being asked, this is a true reflection (on my scale anyway) of their current performance.
 
Once again though, I’d like to pass my thanks to svyr, Empj,  and T-Peos for giving me the chance to try these.
 
RECOMMENDATIONS TO T-PEOS
 
Start again from the Altone 200 – and build a better more balanced IEM from it as a base. I really look forward to seeing what you can do with a different direction.

I've never put in-ears with different drivers in my ears before so I had no idea of what to expect when it came to the T-Peos Altone 350 Hybrid 3 driver IEM. 
 
So thanks to CTC Audio who put the 350s out on tour I plugged them into a Cayin 6 which is also on tour and let fly. My first impression is somebody had plugged a cable directly into the bass guitar. Listening to Bob Marley's Legend was an overwhelming experience. There was a whole lotta music coming into my head and it was tough to sort out. The bass was distinctly present as were the mids and the trebles. I couldn't get them to resolve into the milky (maybe soupy when compared to some of my cheaper headphones) sound I was used to hearing around here.
 
So I kept listening and within about five minutes my brain started to make coherent sense to what I was listening to.
 
There's a whole lot of other guys out there who can describe in more technical terms what I was hearing but what I was hearing was good...it was very good....once I got used to it.
 
The 350s made my Shure 535s sound awfully tame. 
 
That's not necessarily a bad thing. the 350s are really amazing and I'll call it a hot sound. They are by no means as hot a sound as the diminutive $36 T-Peos D-202Ns which CTC Audio characterizes and I think rightly as a "fun sound" and have to be the bargain of the century IMHO. My 535s are a way more laid back and for whiskey-soaked voices of females singers out of the American sound they are perfect but when it comes to Bob Marley singing Buffalo Soldier the 350s take you to Jamaica. It's a humid, hot night and the outdoor stadium is alive with music and ganga and danger. You don't get this from the 535s! LOL I think there's a black man somewhere inside this old white body who knows how to dance!
 
There are a couple of different folks who are going to read this review.
 
Audiophiles are going to find a lot to talk about when it comes to the 350s. They're a little pricey in comparison to all that's out there and the sound is more over-the-top than neutral. The cable is a little microphonic as I can hear the sound as it crosses my jacket zipper. It's not anywhere near as bad as my Seinnheiser CX-300s but it's present.
 
But the good news is if we're going to do a comparison, the 350s are way closer to my Audeze LCD-X sound than my Momentum on-ears. This is a good thing and it gets better. The 350s create an amazingly wide soundstage. I like big soundstage sound. It might not be to everyone's taste but I like what the 350s can do to separate instruments from each other and from singers. There maybe better wider soundstage headphones out there but the 350s are standouts when it comes to my collection of headphones.
 
The other folks who are going to read this review are likely going to buy one set of in-ear headphones to match their one set of over-the-ears or on-ear headphones. So you've got your $400 or so and you're thinking....decisions - decisions.
 
I've not listened to everything that's out there but I've got the LCD-Xs, a Grado 60 (like it so much I bought a set for my teenage niece), a closet full of Sennheisers from the 590 to 439s and more and I can recommend the T-Peos Altone 350s if you're looking for really well-built in-ears that fit (at least they fit me) and create a good seal and are comfortable after a couple of hours of listening. BTW you do get a second set of cables, titanium housing and the regular assortment of accessories. Also I've found CTC Audio folks pretty easy to deal with and that's an important factor these days when so many of us are shopping online.
 
I think it's pretty safe to say the T-Peos Altone 350s (which are T-Peos flagship model) can bring you into the premium quality in-ear headphone world at a decent price especially when you compare what you could spend elsewhere for less. I'll be sorry to see them go back on tour.

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Before I start my review, I would like to Thank CTC Audio for a review loaner in exchange for my honest opinion.

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Last year hybrid IEMs were the talk of the town, and I got a chance to review a few 2-way and 3-way hybrids from different manufacturers.  Among those was Altone 200 from Korean manufacturer T-Peos which left a noticeable impression with me after the review.  It looks like T-Peos hasn’t been sitting still, and following the popularity of Altone model they decided to release an updated lineup with Altone 150, Altone 250, and Altone 350.  Cleverly partitioned into a single dynamic (A150, w/aluminum housing), 2-way dynamic and BA (A250, w/mix of aluminum and titanium housing), and 3-way with a dynamic and 2x BA (350, w/all titanium housing), T-Peos made these new models similar in exterior design with removable cables but distinct in the quality of housing material, amount of accessories, and obvious sound difference driven by additional drivers.  I got a chance to preview their flagship A350 model and would like to share with you my impressions.  Here is what I found.
 
Arrived in a premium quality packaging, I enjoyed a clear front image which covers design details and acknowledges about the removable nature of the cable.  Back of the packaging goes into details of specification list, accessories, in-line remote functionality, and also provides an internal design diagram of components inside of the shell.  I personally enjoy when manufacturer goes in depth with internal design details; it shows a pride and a confidence they have in their product, and it's an eye candy for tech geeks such as myself.
 
Out of the exterior packaging shell, you'll find the inside box with another cover.  Not sure the purpose of that, maybe to add to the premium appeal, but once removed you will find a foam insert tray with cutouts for A350 on display and a large cutout for both of the cables.
 
Unboxing.
 

 

 

 

 

 
 
With everything out of the box, you are presented with an abundance of the accessories in addition to Altone 350 IEM.  First and foremost, you have 2 sets of removable/replacement cables: one is red audio only cable, and the other one is black with inline remote.  You also get a large selection of eartips, including 3 pairs of S/M/L generic medium bore opening silicone gray tips, 3 pairs of bi-color hybrid S/M/L tips with a softer cap dome and slightly larger bore opening, 3 pairs of double-flange black silicone tips with a slight design variation, and a pair of genuine Comply foam Tx-200 tips.  There was also a pair of earhooks, 6.3mm adapter, and a rather interesting cable clip (never seen such before, definitely not a common generic part).  Furthermore, T-Peos included a premium quality leather zipper case.  While the other accessories felt like premium in quantity, I found this case to be unique enough to stand out as a premium quality accessory.
 
Accessories.
 

 

 

 

 

 
 
Before talking about the design, let me first start with a cable.  Both audio and smartphone cables are nearly identical in design with an exception of cable shield color and the inline remote with mic.  Starting with headphone plug, it has a sturdy 90deg connector with a nice strain relief.  Moving up to y-splitter, it has a nice metal cylindrical shape and rubbery ends to form a good strain relief as well.  The inline remote of the black cable was rather bulky considering it has only mic and a single control multi-function button, while the metal frame around it kind of looks like it has touch volume buttons, but it actually doesn't.  Cable is terminated with a slim DC connector (similar to power plugs).  Even so I enjoyed the ease of dealing with such basic connector in comparison to a more common MMCX, you have to be careful not to bend the protruding metal part of it.  Also, due to this being an uncommon connector, don't expect too many aftermarket replacement alternatives.
 
Overall, the cable has a nice sturdy construction, but it's very springy and doesn't stay straight all the way.  It is not as much problem when you wrap it up for storage, which is actually quite manageable to keep under control, but more of a nuisance when you wearing it because I felt it contributed significantly to microphonics effect.  This is where that cool alligator clip might come in handy to keep the cable from rubbing against your cloth.  Also, speaking of wear, I was able to have these in my ears both with wire down and wire up, but felt that wire down had a more natural fitment because A350 doesn't have a deep insertion and shells stick out a bit thus creating not the most comfortable cable fitment angle with wire up (even with earhook).
 
Fitment.
 

 

 
 
The shell itself has a nice weight to it, though it still felt quite comfortable once in your ears.  You definitely feel a premium quality of the build and the titanium material used in the design, and I personally like a cold feel of the metal when these go into my ears (but enough about my fetishes lol!!!).  Even so the fundamental shape of the shell is cylindrical, it has a lot of cool design details when you look closer.  I'm still trying to figure out if there is an air vent opening on the back of the shell since I found soundstage to be above average in width, but at the same time they have a pretty good isolation.  Either way, I couldn't find any obvious pin hole openings.
 
To distinguish left and right sides of earpieces, right one has Red accents and left on has Black accents on the back side, L/R markings, the plastic dc connector base, and a pair of all around grooves filled with corresponding color.  While the rest of the color markings are solid and permanent, those grooves were filled with some kind of a temporary marker color that wipes off.  Since it's inside of the groove, you can't just rub your finger over it, but a brush with a nail wipes them right off like a temporary marker.  Don't think it was even necessary to add color in those grooves, so not a big deal, just a bit strange.
 
Now, going back to the remote control, I think it was a good decision to include only a single multifunction button to make it more universal for Android and iOS phones, since volume implementation control differs between hardware of these two OS.  I would prefer to have the remote a little bit smaller, but it still work fine to Play/Pause/Call with a single click of the button, and skips track forward with a double click.  Triple click to skip back didn't work.  Also, phone call quality was good, though I don't have access to super "noisy" environment.
 
Design.
 

 

 

 

 

 

 

 

 

 

 
 
I approached the sound test of A350 with a little caution.  Even so I was impressed with 3-way hybrid design and build quality of Altone 200, for my personal taste a region of upper mids and treble was too hot while at the same time the quality and the resolution of bass was among the best I heard.  With A350 roles got reversed.  Ironically, while I was looking to use narrow bore large size tips to tame down A200 treble, with A350 I was looking for wide opening bore tips to get the bass under control.  YMMV since this is a matter of a personal sound taste, but I felt a lot better after applying 3dB cut around 60Hz region to get the weight of the bass under control.  But without any EQ, here is a more detailed perception of A350 sound.
 
As I already mentioned, low end feels a little heavy due to elevated sub-bass and mid-bass hump.  At the same time, I didn't feel any spillage into lower mids, more like overshadowing it.
 
Mids felt a bit recessed relative to low end due to a contrast between elevated bass and thinned out lower mids.  Upper mids were bright, clear, detailed and slightly grainy, maybe even closer to analytical level without feeling too harsh.  Unfortunately, lack of body in mids made vocals sound thin as well, definitely less organic.
 
Never thought I'm gonna say this, but I actually found treble to be my favorite part of A350 tuning.  It is no longer as sibilant and harsh as it was with A200 (relative to my perception), and it still has a great extension and crisp details.
 
As I stated before, I found soundstage to be above average in width with just an average depth.  Separation and imaging was better at lower volume, but as I raised the volume up a sound became a bit shoutty and slightly congested.  Headphones itself were relatively efficient and didn't require any amping.  Also, as mentioned before, they respond great to EQ where I had to apply a cut to tame down the bass.
 
Relative to other IEMs, I found the following while doing a/b comparison.
 
- vs A350, A83 bass has more punch with less sub-bass weight, mids are a little thicker and more forward (lower mids have more body, while upper mids are similar), treble is crisp but doesn't extend as far though it's a bit harsher in comparison to A350; soundstage is wider and deeper and a sound has a better layering/separation.
 
- vs A350, IM03 has a lot warmer and smoother sound with a better balance of lower quantity sub-bass and faster mid-bass, thicker mids (more body in lower mids and smoother upper mids), treble is smoother and not as extended; soundstage is similar.
 
- vs A350, W40 has a lower bass quantity with a more relaxed mid-bass and less sub-bass, mids are more balanced as well and slightly more forward in comparison, also mids are smoother and with more warmer body, treble has less extension and not as bright; soundstage is wider.
 
- vs A350, CKR10 has warmer and smoother sound, a more controlled bass with a better balance between sub- and mid-bass, thicker and more upfront mids that sound more organic and smoother, treble has a good extension but not as crisp as A350.
 
- vs A350, A200 has a more v-shaped signature, bass was more detailed and better controlled, mids were more recessed with lower mids being similarly on a thinner side while upper mids being brighter and more vivid.  Treble was also a bit harsher, crossing sibilance level in my book.
 
Conclusion.
 
In my opinion, there are two different ways how people approach a review, as a consumer who paid money to own the product (and consequently will let you know if he/she got their money worth) and as a reviewer who is approached by manufacturer/retailer to provide their honest opinion about the product.  We me being in a category of the later one, I think it's more appropriate to present headphones as I hear it and let my readers decide if it's a right product for them.  The truth of the matter is that T-Peos Altone 350 has a rather unique sound characteristics to satisfy a craving of basshead audiophile who wants an analytical vivid details with a serious bass slam.  Additionally, if you consider two sets of sturdy replacement cables, a titanium housing, and a ton of accessories - you can make an argument that someone will find this package to be very appealing at a price tag approaching $400 mark.  Although I didn't find their signature to be exactly my cup of tea, I'm sure there are going to be others who wouldn't want to miss this tea party!

Foreword:
 
I'm a production manager, but focus mostly on sound engineering. I install and tune a lot of P.A equipment, and also mix live acts in :

- live venues,
- concert halls,
- bars, and
- nightclubs.

I've taken a huge liking to headphones, and IEM's in particular. I like the idea of having my own personal PA system, that I can take with me anywhere. Especially with Rockbox being in such advanced stages, and such great low-impedance portable amps coming out, you can really seem to get any sound signature you wish out of a portable rig.
 

T-PEOS Altone350 review.
 

 
 
Build quality and accessories:
These in-ears are a premium product from T-PEOS, and as such, have a premium presentation, and a price tag to match.
I won't cover each and every accessory, as other reviews have done a great job of that. But just know, that it's a very generous helping of accessories.
 
A few things that jumped out at me whilst I was unboxing these:
 

1. IEM Housing is created entirely from titanium
2. Premium carry pouch, which I assume is genuine leather
3. Two different cables to choose from. One had an inline remote.
4. Great selection of tips, including Comply tips (not just generic foamies)
5. Although stated as 8 grams, these felt a little heavier that normal bullet type IEMs.
6. Wide-nozzle at the tip – this matters to some, but is irrelevant to most.
7. The L and R markings on the IEMs seemed to be rubbing off a little.
8. Both cables are twisted and insulated – and produce quite a lot of cable rubbing/tapping noise.
    

 

 
 
Feel/comfort:
They require only a fairly shallow insertion. The eight grams of weight are instantly not noticeable once these are worn. The isolation will change depending on the tips worn, but they will isolate as well as any other shallow-inserted IEM with olive tips.
The cable noise was an issue for me. Anything tapping the cable above the Y-split would be clearly audible inside the ear-pieces. Rubbing the cable below the Y-split was also audible. My personal preference is for something similar to the Westone EPIC style cable.
 
These IEMs feature a wide-bore design, similar to other products from this company. This was not an issue for me, and I found them quite comfortable – once I found the right tips.
 

 
Specs:
From the CTC Audio website:
 
Type: In-Ear Monitor (IEM) 
Driver: Dual Balanced Armature Driver + Exclusive 10mm Dynamic Driver (HPS)
SPL: 105dB / 1kHz
Impedance: 22Ω 
Frequency Response: 20Hz~20KHz 
Max Power Input: 100mW
Plug: 3.5mm 24k Gold-Plated, L-Type
Cables: 2x detachable cables - 1 with microphone, 1 without. 
Weight: 8g (Without Cable)
Warranty: 1-year Manufacturer; CTC Audio Exclusive 180-day Warranty
 

 

 

Sound:
 
Bass:
The bass is dynamic, tight yet punchy. It's definitely not bloated. It has a good amount of “kick” and a bit less “rumble”. Depending on your personal listening tastes, this may or may not be an issue.
 
I found the bass responded very well to EQ. The 10mm driver delivers more than enough punch when you supply the juice to it.
 
Other offerings I've tried from this company have also responded well to bass EQ – great job guys.
 
For my personal (basshead) tastes, out of the box, the quality of both sub-bass and mid-bass was fantastic, but the quanitity was not enough to satisfy my personal needs.
 
Mids:
A clear, separated midrage. Accurate, with forward upper-mids. These will sit well with you, if you're into that spine-chilling vocalist moment. I didn't have any issues with congestion, and if I had to describe the mids in one word, I would say “accurate”.
There were no detectable “problem areas” that stuck out to me, or were too offensive.
 
High:
there was a noticeable sizzle around the 9-10k mark. A lot of people enjoy this peak, as it can give a lot of detail. I personally listen at a decent volume, and this sizzle is a game-breaker for me. If you're going to be using this IEM, be warned – without EQ, you will want to listen to it at reasonable, normal levels.
There was a satisfying amount of detail, and it didn't sound recessed or muddled at all.
 
Value:
At almost $400 US, this is quite a pricey offering from this company. They are entering a very well populated price-bracket. The included accessories and build quality definitely put them up a notch, but I personally wouldn't pay $400 US for them.
 
Comparisons:
 

 
I know it's “unfair” to compare these to my far more expensive musician monitors, but they are the only other IEMs I had sitting around. Please read into this for comparisons sake only, and not as a competition.
 
Compared to the Unique Melody Merlin:
350 is brighter
350 is more detailed
Merlin is more laid back
Merlin is darker, thicker
Merlin has far more bass
350 has clearer vocals
 

 

 
 
Compared to the Westone ES3X:
Es3x has slightly more bass
350 is brighter
350 more detailed
Es3x can be comfortably listened to at louder volumes
350 has less midbass hump
Better soundstage on 350
More realistic sound from 350
350 more sibilant on specific recordings.

 


Overall conclusion:
 
A great premium offering, with a price tag to match. A little too much sizzle for my tastes, and some very great accessories.  

T-Peos were kind enough to organize a T-Peos Altone 350 (I'll refer to it as A350) unit for a private head-fi Australian review tour .
Previously, we arranged tour units via T-Peos (e.g. with H300). This time a sample unit was arranged via CTCAudio. , they're T-PEOS's distributor in North America (both are sponsors at head-fi and CTCAudio, the members are mobyn and empj) )

Altone 350 is the new flagship for T-PEOS's Altone line . Looking at the pricing and design, T-PEOS likely merged in the H-2/300 series into the Altone line at least for now.
Inside the titanium polished body you'll find 3 drivers - a Knowles TWFK (dual Balanced armature (2BA)) and a Dynamic driver (DD) - a hybrid configuration. There are nice CGI pictures of how it and the crossover fit inside in the links below.
'3way' on the box, refers to 2 crossover points between the drivers - one for the dynamic driver, one for the TWFK - between the two BAs.
Retailing at around $400 US this is the most expensive product from T-PEOS to date.

You can read a bit more (translated for the Korean site links) here. here and here . You'll also find some more decent pics and measurements in those links (FR+THD+N). For the H300 measurements, I was looking at here

T-PEOS A350 is a part of their new hybrid product line (Altone 250,350. 150 is a single DD. 250 is an Knowles FK-1BA + DD).
A350 is their fourth 2BA+DD model (h200->h300->altone200->Altone 350)

(let's digress a bit on their previous products): I think it's fair to say a few people around here like the value proposition of H300 and Altone 200.
Personally, I like A200 a bit less - it's a bit dark for me in terms of treble extension (not the 7khz peak) (although I do like the mids and bass on a200). H300 is a bit too bright and cold in the mids (and has a giant 7khz centered treble spike), but I think with minimum equalization (EQing) using rockbox they sound pretty great (H300 - not just for the price but overall vs much more expensive earphones). Both are quite affordable. Initially H300 was even more affordable. At the moment I prefer EQed H300 to most of the current universal hybrids - having heard a few of those


L->R - A350, H300, A200 (prototype). not pictured Dunu Titan1 =)



design:

I like the titanium body. I'm not sure how well polished metal will keep overtime (fingerprints aside), but it feels more durable than the painted finish for h300 (after over a year the body on H300 is almost entirely covered by small scratches).
on A350 There are a few plastic inserts at the back of the body.
The (removable) cable socket is held in place by cube of plastic that merges into a plastic cylinder at the back of the earpiece (under the titanium and bits of the cylinder are see-through). It looks like body is compose of 2 titanium halves, glued or clamped around the plastic insert.

After a week with me - there are a few small micro scratches on the sample unit but those are barely visible. There's also a slightly larger one - I suspect earpiece on earpiece but intentionally trying to scratch an earpiece with a brass key didn't leave a mark. The plastic might chip too. Overall, I'm not really worried about durability. Hopefully the glue is better than the h300 glue though (if it's not clamped instead of glued).


The cable plug is similar to thin DC charges ones). It's difficult to say whether the cable not being MMCX or CM is good or not. It does support the bullet design when worn down. but impedes wearing them over the ear slightly (aside from interchangeability 'from your collection' issues). I've never had issues with H300 plugs in terms of them getting dirty or breaking (which can't be said for MMCX or CM sockets/plugs)


What I definitely didn't like was the black and red lines on the body....Those are felt tip pen or marker or something similar ... They um smudged/rubbed off.





fit/isolation:
A350 are shallow-mid insertion bullet type IEMs.
Isolation is adequate with comply tips (probably 8-10dB - enough to softer some of the external noise on its own and most of the time with reasonable volume music block out the world for you - e.g. on a bus)

For me they fit better than H300. I'm not sure why (exact same comply tips and both units look to be very similar in size (I've started at different angles for about 10 minutes)). H-300 becomes a bit uncomfortable and lose after a while (30-40m), but no issues with A350. I can see the profile of the two is nearly identical in terms of dimensions, but maybe the A350 has a smaller post nozzle pre outer body (middle section). Maybe it's also the cut-out sections of the body at the rear of the uni on the a350.

A350 are also larger than altone200 (which was hands down the most comfortable 3 driver hybrid IEM I used ) but I suspect we won't get 2BA+DD anytime soon that are as small as that (especially not with a removable cable)

I found with comply tips I can listen to these comfortably for 2-3h without issues from physical discomfort. Minimal adjustments are requiring when walking or light jogging. (provided I use the clip)


Accessories:

A (some minor qualms but very nice - mostly whatever H300 had or an improvement on that)
-nice leather case - bit too big for eaphones on their own. but will fit some of the accessories and a clip+. It's also... brown-orange.
-a good selection of tips suitable for bullet type earphones. Silicon of all sizes and several core types, bi-flange tips.
Foam tips are under-represented by a single med comply tx200 set. (it's better than the red foam tips before, but would be good if L/M/S were included )
-3.5->6.3mm adapter
-shirt clip. It's really large - the size of 2x a350 earphones. I think someone mentioned - the larger ones lead to less cable noise but it's way too bit. Also, it's a 'locking' clip (you put force on it to close it and it stays there requiring you to unlock), so if you catch the cord on a tree branch, the clip won't loosen and generally, the earphones will get ripped out of your ears. I like smaller clips a lot more. (you can also slide smaller clips along your shirt more easily and they
-cables: Looking at the marketing material - these are now twisted pair (4 conductors it says on the box) cables with a rubbery plastic on top. I really disliked the H300 green cable - RMAed it twice for insulation near the plug breaking. The new cables looks like they'll last better and the cable plug is looking nicer as well.
You get two cables and - red (plain) and black (remote - play pause). That's always welcome for android users (and I think people mentioned works with iphones for H300). I would have preferred to see a 3 button cable (recently tried play/pause volume ones and really miss them). One other thing that's missing is a chin guard ring (to adjust the lose y-split wire length). I've previously asked T-Peos to reinclude it but unfortunately they didn't.
The cables do tangle up a bit in my pocket.
-earguides (you can use them to wear A350 over the ear,but I didn't like doing that for fiddling/getting the exact angle hard comfort reasons)

sound

Looking at the Frequency response graph on Seeko - T-PEOS probably aimed for more balanced earphones vs H300.

on low volumes I probably avoid EQing them and they sound balanced on the bright side (as in punchy bass, sweet enough mids, but a touch bright in the treble and great otherwise). I really quite like brighter tunings on lower volumes.

Normally I listen a bit louder - around 20-25 on clip+ with Rockbox, depending on EQ and pre-cut settings) and A350 sound a bit different there.

Treble: There is a spike closer to 9khz on A350. It's above the sibilance area, but it's the 'HOT' treble area for some. You won't necessarily hear it on all the tracks either. The spike is smaller than on H300 (about 10dB vs 15db)
UNeqed listening to metal I get fatigue from the treble in under 30m. Peak aside- the treble resolution is good. Although past the peaks, H300 is more detailed. Personally I can't listen to either without equalizing the peak down. Extension is similar to H300, but I think H300 feels more detailed as it has more treble content 5-10k . We'll come back to the 5k dip later.

MidsH300 felt a bit cold because of the treble spike (there it was at 8.3k) and because upper mids (2-3k) were more prominent then 1k. For A350 the mids definitely feel warmer and require no adjustment. (there's no more 2-3k peak). Like with H300 a200, for 350 - the impressive resolution and clarity are there (ps I did see the THD+N spikes on the seeko chart =) but can't hear it). I'm fairly sure mids tuning is quite similar to altone200 - full, good clarity, good balance of upper and lower mids. I can't really fault it for metal, classical (solo violin or piano or male or female vocals ) or D'n'B .


Bass: Deep sub-bass, nice bass (~H300), quite a bit of mid-bass (>H300).
There's a bit bass overall vs H300 and it hits a bit less hard and sometimes might sound a bit muddy if you try to EQ it up (we'll come back to that a bit later).
I like it about the same as the Altone200 bass, and definitely more than Dunu DN2000 or Titan1 bass. Much better impact and clarity on the bass and I prefer the sub-bass to mid bass ratio on A350.

So overall it's a more balanced variation on H300 (or if you like A200+H300). Less spikey treble, richer perceived lower mids vs upper mids (less cold) and err less emphasized sub-bass/bass. I do like both for anything from metal, d'n'b rock, classical (piano+orchestra or violin+orchestra) and a bit of jazz. Out of the box A350 will probably lend itself better to vocals and piano/violin as it's a bit fuller in them mids.

soundstage
adequate. it's less broad or deep than Titan1 in terms of expansiveness . Because of the mids tuning they also feel overall more intimate to H300.

What I didn't quite like.
After listening to H300 and A350 side by side for a few hours slightly EQed VS UNEQed I realized the following:

1) I thought while A350 punch hard, the sub-bass and bass speed/clarity on H300 feels faster.
If we believe the charts it could be explained by H300 having about 15dB bass boost at 50hz vs 1khz (vs 10 for A350) and a hump 30hz-100hz (vs linear there for a350). Moreover the mid-bass to lower mids (120-200) vs sub-bass and bass is linear on A350, whereas for H300 you get a nice increase lower mids->sub-bass . So to me, on some songs A350 sounds a bit muddier and dilutes the overall punch vs H300 to me because of that.

Don't get me wrong, A350 unEQed bass is still good, but H300 is amazing for realistic, clean, fast, punchy bass. There are some hip-hop or D'n'B or even jazz tracks where you will notice the sub-bass difference where A350 won't punch as hard and feel a bit muddy.

H300 was easily correctable with the Eq in the appendix. I've also included what i think tentatively works well for the A350.


2) There's also a bit of ringing at 3.5kHz (not much), and at 9kHz. The 9kHz peak was discussed above and for me is definitely fatiguing .
3) There's also a 5kHz DIP. I'm undecided about the 3.5-5kHz-7 dip. I know it was debated quite a bit in the noble 3/4 thread, and it was a point for h200 (more prominent for the latter as per here). I also realize a few instruments have overtones, re crispness or attack at 4-7kHz
Personally I'm not that sensitive to the dip but I do find H300 has better clarity overall while having a smaller 5k DIP, and more overall treble energy 5-12k.

At the same time 5k and 7k are also most prominent for sibilance which the dip at 5kHz probably helps to avoid (not the case for A350, but was the case for H300, where the treble peak was shifted to 8kHz not 9kHz). ps from memory was one way of tuning the second cross-over depending on the design choices leads to this dip for TWFK drivers.
4) It's still a bit large vs Altone200 in terms of physical size


Overall
As a H300 owner - I like the new housing/fit and cables, and I think overall the improvements to sound are great.
I don't quite like the bass and treble tuning vs H300 that much though so I'm not sure I just can't justify the US$400 ($500 AUD price tag).
It's also very hard to put $400 aside after Altone200 was <$200 at some point
It's undoubtedly a versatile IEM, even unEQed will find many fans.
But at times it feels like the polite cousin of H300, whereas H300 is like jumping on a rocket dragon - insane amounts of fun past taming the treble energy that will probably otherwise burn you alive.


Appendix 1: EQ settings - rockbox graphical EQ:
A350 (tentative - based on about 1h of trying, assisted with seeko.kr graphs)
pre-cut -5
f=30, q=1.3, db=+5
f=50,q=1.7,db=+3.5
f=150,q=1,db=-2.5
f=800,q=1.6,db=0.7
f=1750,q=1,db=1.8
f=4750,q=1,db=2
f=9000,q=0.7,db=-0.7

H300 (bump up the bass punch, sweeten the mids and tone down the treble razors of death)
pre-cut -5
f=50, q=1.5, db=+5
f=800, q=1.6, db=1
f=1250, q=0.8, db=2
f=8350, q=0.7, db=-2.8