
HISENIOR is a Chinese audio company specializing in custom in-ear for musicians, studio engineer and audiophiles. They mostly create multi balanced armature earphones using Knowles ba, as well as hybrid IEM. This company is well known in China, but still obscure to western consumers.
This company give a lot of care about tuning and aren't afraid to share actual frequencies response graphic of their creation. The house sound target seems to be about clarity and balance, but some CIEM are specifically tuned for musician's need too.
As a big fan of Knowles BA earphones which can found either in my beloved Audiosense T800, FIIO FH7 and FA9 or IKKO OH10, I decide to contact HISENIOR to review the B5, which is a 5 Knowles ba UIEM. After having communicated more with Hisenior agent, I understand that BA models used in T2U model are of higher quality and the tuning seems more balanced and refined, so this is the model I will review today.

The Hisenior T2U uses 2 high-ends Knowles BA, the CI-22955 for lows and mids and the CI-29689 for highs. The housing body is made of high-grade Allergy-free resin material and has a mmcx connector. While the normal price should be 160$, the T2U is on sale for undetermined time for as low as 80$ on the official website. As well, the custom version call T2 is selling for 100$.
I didn't know exactly what to expect from Hisenior, but my long exchange with it's staff was very revealing about the seriousness of their tuning work, it seems they really know what they do and have a lof of experience with a wide range of Knowles BA drivers.
One thing sure, I didn't forget the 160$ official price, so when I put these in my ears I was in a rather critical listening mode that expects a mature audiophile sound. And let's say it right now: I was blown away by the crisp balanced sound the T2U delivers. Let's see why in this review.
I urge you to buy the HISENIOR T2U from official STORE while the bargain 80$ price still last.
SPECS
Specifications
Drivers 2 knowles Balanced Armature Drivers
Configuration 1 Low and Mid + 1 High
Crossover 2-Way Passive Crossover/ Dual-Bores/2Dampers
Freq Response 20Hz-20Khz
Sensitivity 105dB/mW
Impedance 18Ω
Isolation -18db
Design Transparent shell and Solid Black faceplate
ACCESSORIES & CONSTRUCTION

The T2U didn't come into an official package, so I'll bypass unboxing impressions and go right into the generous amount of accessories it includes. Something I really like to get is a pelican-like protective case with enough space to put more than one IEM and cable, and this is exactly what we got with the T2U, its a unique one with Hisenior logo on top. Inside it you have a nice quality braided cable, a wide range of eartips including both silicone and memory foam, a cleaning cloth and even a 3.5mm to 2.5mm balanced converter. Not sure the use of this converter, but i suspect it work better with 3.5mm balanced cable.

CONSTRUCTION is very nice, light and sturdy. Housing is rather small for a UIEM and uses a good quality resin material which feels very solid in hands unlike cheap plastic often use. Nozzle has good length and the organic shape permit deeper insertion without discomfort. The backplate design is elegant with its glossy metal Hisenior Logo. All housing being sealed mean it has good (not specified) waterproof potential too if you use a mmcx cable with flush fit.
The 4 strands OCC CABLE is of nice quality enough, especially the weighty sturdy metal jack but the Hisenior do benefit from cable upgrade as they are true audiophile earphones that need cleanest sound transmission possible.
The housing DESIGN has a very ergonomic shape that will probably fit every ear because of how small and light is the body. These IEM are among the more comfortable ones I own, but it must be noted that ear tips used will drastically inflict on proper sound rendering so this can be a little annoying. I find this very common with multi-ba IEM which benefits wide bore ear tips to sound their best.
Depending of how deep you'll insert the T2U, the ISOLATION can go from good to excellent. Hisenior state a isolation of -18db using memory foam tips. As well, sound leakage is very minimal even at high volume.
DRIVEABILITY is quite easy at 18ohm of impedance and 105db of sensitivity, and the good news is that unlike numerous Multi BA earphones, they aren't capricious about impedance output of your audio source, so no background hissing or distortion with those as found with too sensitive IEM. The T2U do benefit from an ultra-clean powerful audio source and tends to pair less well with warm or not enough transparent audio source.
SOUND

The overall sound is crisp in resolution and smooth in timbre, with a high level of transparency, impressive bass response for dual BA and detailed yet inoffensive treble. We are in beautifully balanced L shape territory, where the bass and mid-bass is gently pumped up to offer lusher overall presentation and everything feels cohesively full in timbre without lacking anything in both technicality and tonality.
SOUNDSTAGE has great deepness and wideness but average tallness, ear tips fitting affect drastically spatial projection and should be tested thoroughly. Wide bore ear tips tend to open the soundstage a lot and put the bass slightly in the back, which makes the T2U more neutral and airy.
IMAGING is very precise in stereo direction with a very impressive amount of layers deepness as if highs are more spacious in separation while mids and bass are more about layering.
TIMBRE is smooth, realist, have an airy density that permits great transparency and refined texture free of grain or compressed saturation.
BASS is fast and punchy, with a hint of warmth coming from the lean mid-bass bump. You don't have a lot of rumbles and heavy slam, even if sub-bass lines are well-bodied and have good articulation so you can feel the lower end. Both quantity and quality of bass is excellent for dual balanced armature, as well, it never distorts or sounds overly rolled off. We can say the T2U is a bassy IEM, not to the Audiosense T800 bass head level but still above neutral level, and while the punch isn't the tightest one and have slightly muffled impact, the weight is there as well as the oomph. The texture is smooth, so the kick drum will lack some bite and details, but not to the point of sounding dull because of fast (unedgy) attack and clean separation from lower bass.
MIDS are flat and full with a good amount of lower mids so both male and female vocal have the same presence in thickness. It doesn't feel recessed and we have a minimal amount of bass warmth for a natural transition in tonal balance. Clarity is excellent, offering very clean and articulate presentation with a slightly intimate and well-centered approach. Mid-range is rich in well articulate sound layers, free of any harshness or sibilance and have a hint of liquid texture to it, it isn't particularly bright because of smoothed edge and natural tonality. Though the definition is very good, it's not very snappy in attack dynamics. Vocal and instrument like piano and saxophone tends to sound more realist than electric guitar due to tamed attack. Some may find the mids a little thin in timbre, but it isnt dry neither lacking in transparent density.
TREBLE is the more vivid part of the T2U, it's snappy and delicate with a charming brilliance and fast sparkly attack. Though very well balanced with rest of sound spectrum, highs sound more energic and higher in definition than lows and mids, it add liveliness to whole sound as well as air in instrument separation. Attack decay isn't very long and permits high intelligibility of a wide range of micro-details. I don't consider the treble to be particularly bright, this is surely due to a rather smooth timbre and very clean tonality. Talking about timbre, it isn't the fullest and tends to push higher harmonic forwards in the sense it's very crisp but not dense, snare and woodblock lack a bit of roundness even if super snappy in attack and clean in resolution. Violin sounds slightly liquid in texture, while instruments like clavichord, harp or acoustic guitar have an appealing metallic bit to them. Another impressive aspect is the fast transient speed that permits excellent macro-resolution of fast busy music passage often found in jazz-rock. While the treble is both versatile and permissive and will do great with about any music from electronic to folk to jazz to soul, it could lack a bit of brightness in texture and bite in attack for electric guitar and violin.
QUANTITY | QUALITY |
BASS: 8/10 | 7.5/10 |
MIDS: 8/10 | 8.5/10 |
TREBLE: 8.5/10 | 8.5/10 |
ATTACK-DECAY: 8/10 | 8/10 |
SOUNDSTAGE-IMAGING: 8/10 TIMBRE-TEXTURE: 7.5/10 | 8.5/10 8.5/10 |

So, the (official) graph of T2U gives you a hint about overall tonality, but what I personally hear isn't as bassy as this graph suggests. To my ears, the bass sits behind the mids in a very lean manner, but the high bass drop does translate a slight lack of weight in mid-bass punch. As seen, lower mids are rather pushed forwards and this is good, it mean they are fully extended and offer natural presence with a hint of warmth. No important peaks in upper mids or treble is what I hear too, because the T2U is an overall very smooth sounding IEM. Not sure if a sudden drop around 8khz is accurate because I do find the T2U well detailed and even quite sparkly for a balanced armature IEM. Moral of the story is: don't be afraid of this 5db bass boost, it isn't either a basshead or V shape IEM, it's a full sounding neutral one.
COMPARISONS

VS FIIO FD1 (70$)
TONALITY of T2U is leaner and crisper, with smoother timbre, better transparency and more neutral tuning.
SOUNDSTAGE is notably deeper and slightly less wide. IMAGING is way better with more precision and accuracy in instrument placement and separation.
BASS is similar, but in a more recessed way, it’s punchy and faster-tighter with clearer separation. It has little less extension and rumble in lower region.
MIDS are crisper with better transparency and more edgy attack, it’s thinner in timbre and vocal are more intimate and centered. Sibilance is less evident too.
TREBLE is more delicate, better balanced, fuller and more analytical. It’s less grainy too.
In term of technicalities, the T2 is leagues ahead, but it sounds slightly colder and vocal might be more appealing with FD1 for lot of people.
VS AUDIOSENSE T260 (60$)
The T260 use dual Knowles BA too and while we have some similarity in timbre, tonal balance doesn't take same tuning road.
SOUNDSTAGE is about as wide but not as deep as T2U, imaging isn't as transparent in layering and can feel over-saturated
BASS is more sloppy and lack in weight and extension compared to T2U which is more controlled and full. It's slightly more textured, but not in a natural way.
MIDS are less clean and well separated, they are brighter too and more forwards.
TREBLE have more low and mid highs emphasis, it's less well balanced and thigh in attack, as well we have less sparkle. The overall presentation is more shouty, though not in an aggressive way.
All in all, the T2U have better technicalities and is way more balanced and accurate than T260.
VS BRAINWAVZ B400 (200$)
Now we have a quad Knowles BA and while it feels as an unfair fight, the nicely balanced sound of T2U doesn't feel from a lower league.
SOUNDSTAGE is wider and deeper with the T2U, IMAGING is more spacious in separation but not as rich in sound layers.
BASS is warmer and slightly boomier with the B400, as well, it isn't as clean and well separated from mids and bleed more.
MIDS are lusher and thicker with the B400, vocal is more upfront but not as clean and transparent.
TREBLE is more recessed with the B400, highs are less snappy and sparkly and micro-details aren't as easy to find.
All in all, both are great IEM but the T2U offers a more mature and refined tuning that is more neutral and resolved than more colored, laid back and lush sounding B400.
CONCLUSION

I review the HISENIOR T2U as if it will always sell for 80$, and if it does, it sure put them among the very best sub-100$ UIEM an audiophile can get. This isn't your normal Dual BA budget IEM for multiple reason, firstly being the quality of balanced armature used which are from top of the line Knowles company, secondly because of both built and whole accessories package.
The T2U achieve a rare (and precious) balanced sound signature that finds it's placed between neutrality and L shape extra bass presence, the cohesion of both drivers is natural and effortless, and didn't try to over color any region apart from a needed bass boost that is there to compensate inherent balanced armature limitation in the low end.
If you search a UIEM that offer audiophile-grade sound quality where both technicality and tonality surpass it's price range to deliver an accurate life-like cohesive sound experience, the Hisenior T2U might be the best answer in sub-100$ price range.