TANGZU Wu Zetian – Purple haze

Planar speed and resolving power
Good imaging chops for a planar

Treble extension

Disclaimer: This unit was provided by Linsoul for free in exchange for a written review. No incentives of any kind were given and the review you are about to read are my own thoughts and opinions. Thanks once again to Linsoul for the opportunity and support.

Table of Contents

  1. Prologue and Accessories
  2. Sound
    1. Sub-bass
    2. Mid-bass
    3. Mid-range
    4. Treble
    5. Technical chops
  3. Comparisons
    1. Sub-bass
    2. Mid-bass
    3. Mid-range
    4. Treble
    5. Technicalities
    6. The bottom line
  4. The verdict

Driver Setup: 14.5mm Planar Driver
Price: $150
Purchase link and info: Linsoul
Included in the box:

  • Standard 2pin cable with a 3.5mm termination – there is also a 4.4mm option as far as I know;
  • 8 pairs of silicone tips – 3 balanced (BGVP A07), 3 bass enhanced (BGVP A08), 2 random ones;
  • A storing case;
  • Paperwork and warranty.

Comfort, fit and isolation: Not the best, on the average side. Tip-roll advised.
Source used: Topping E30 + L30 stack, Singxer SA-1, Qudelix5k, ES100 Mk2
Tips used: Final E
Volume used during critical listening: 77db @ 440 hz
Test playlist with some of the songs used: Tidal

Prologue and Accessories

And… Another one.

Yes, you all already know by now, “the year of the planar”, so on and so forth. Today I’m going to take a dive into a not-so-common brand called TANGZU. If my secret intelligence’s notes aren’t wrong, TANGZU is the former TForce, who was known for its Yuan Li release last year.

Despite the new branding, the box and accessories of the Wu Zetian (WZ from now on, bare with me) are very reminiscent of the box included with the Yuan Li, but the content is different.

Inside the giant (for an IEM) cardbox, there’s three accessories I want to superficially cover:

  • Tips: If you paid attention to most of my last reviews, I have been using BGVP tips more and more, especifically the W01 (ultra wide-bore) and the A07 (medium-bore). The A07 tips are included inside the box, alongside the A08, both in three sizes.
    Thich is a great touch, given I enjoy them. If you end up buying a set, give them a go.
  • Cable: The cable included isn’t the best feeling ever, or some might even argue that aesthetically speaking, not even a great match for the WZ, but it sure feels nice and looks great. I’ve used it for the entire time of my listening time, other than for critical listening and direct comparisons, given that I need 4.4mm due to my amp characteristics and ease of volume matching. To note that you can purchase it with a 4.4mm termination.
  • Case: Best. Case. Ever. Well it is technically a tie.
    Before bringing out the pitchforks, hear me out. You won’t be carrying this in your pocket unless you’re Doraemon or a kangaroo, that’s for sure. But for storing away your IEMs, this case is insane. A couple of weeks ago I praised the Dioko and Mahina cases for their premium feel and storage safety, but it takes way too much space compared to TANGZU’s. And this one looks MUCH better. The interior still feels more premium in the other two, if I have to be honest
    I want one of these for each of my higher IEMs. TANGZU, if you are reading this, feel free to send me a dozen, I won’t tell anyone!

After checking my ramble meter, I think I already spent the weekly quota, so time to get serious and dive into the sound. Given the quantity of planars surfacing (and with more yet still to be launched), I will be focusing more on the comparison side of the review than on the Wu Zetian alone, for everyone’s sanity and time. I’ve spent a lot of time trying to build a solid comparison between three planars that, from now on, will serve as the baseline of anything else coming.

Since Timeless, everyone is trying to find the next cool kid on the block, so without further ado, let’s dive into the sound.


The Wu Zetian is a V-Shaped planar monitor like most of its competition. The bass shelf is really well done and correcting itself around the 400hz mark, followed by a not so sudden rise in the pinna gain region, peaking close to the 3k hertz, who then plateaus until 5k, without any fatiguing peaks.

Despite what the graph shows, the 8k region is a coupler’s artifact and the treble is indeed darker than it shows on the graph. By sweeping it, I found the extension peak to be around the 12k hertz region, but without being overly present.

But what does this mean, when actually listening to music? You probably know how this works by now, so let’s get going!


Hans Zimmer – Why So Serious? (Sub-bass drop around 3:25m)

The replay of this modern classic by Zimmer is the best, by a margin, that I have heard from any planar. The sub-bass focus shelf and its high elevation, combined with the planar speed have nothing to be overlooked for, and show a great sense of rumbling and extension. Around this price bracket, it doesn’t get much better, as far as I recall.


Mark Lettieri – Magnetar

Once again, this epic bassline is called to analyze one more IEM.

From the bass guitar to the drum’s pedal, everything has a sense of taticality to it, that can be felt physically. The well done bass glides into the mid-range pops this frequency just enough to be present, with bass guitars sound just right and not overshadowed, or thrown into the background and mixed with the rest of the song, making you look up for it.

Again, all of this allied with planar speed just cut out a very clean, precise but palatable mid-bass region, with enough weight on the scale but without blurring any note. Planars are experts on this but, in my opinion, WZ elevates it half a step up, being the best replay of a bassline from all the planars I’ve tried.


The mid-range is recessed, or wouldn’t it be a V-shaped IEM. The great thing about this mid-range is that, despite what graphs would tell otherwise, there is no bleed into the mid-range by the bass shelf, meaning there’s no mud or overly sense of warmth across this area. With that being a well-known planar characteristic, instead we have a clean and transparent mid-range section, despite its tonality.

Govi – Espresso

Instead of the usual pianos, I decided to include Espresso by Govi, so that right from the start you can see how a clear and detailed mid-range works. The tiny details like finger sliding and cords vibrations pop up, the more resolving an IEM is.

Wu Zetian is no different. All the information is in there and it is very clean, sinning only by its recessed tonality. I don’t find the midrange of this IEM excessively recessed, or else it wouldn’t fit my library, but it is indeed a V-shape.

So, why don’t I hate it? Well, the planar resolving power is compensating for that flaw, making sure all the information is still there and not lost like a mashed potato that would happen with a single dynamic driver around this price and with this tuning.

Govi’s slides, pulls and releases on each chord are still there, just not in your face. Once other instruments show up, it has separation enough to keep this replay going.

Karen Souza – Tainted Love

The female vocals are replayed forwardly on the Wu Zetian, and Karen Souza is no exception. The reason I did choose this track and generally like it on planars revolves around the micro details on her voice.

When well done, you can hear every lip sound, every voice crack or the rispy sounds on their voices. Wu Zetian doesn’t not have the best female vocals in the hobby, but it sure doesn’t fall short when around this. 

Due to its sharp transients and tuning, the vocals have enough bite to not feel dull but never shouty or fatiguing. If I had to nitpick, I would say it could use better extension on their harmonics, but that’s just that.

Postmodern Jukebox – Can’t Feel My Face

If I give it a clear pass on the female vocals, I won’t be so soft regarding its male counterpart – as seen before in other planars, male vocals fall short of my expectations.

Casey Abrams’ vocals take a set back in the replay, blending with the rest of the track too easily and showing lack of bite or even sounding slightly undefined. 

I would categorize these vocals as neutral or slightly recessed, just like the majority of Wu Zetian’s mid-range, going further back down the deeper the vocalist’s voice, sounding better on something like the higher pitch vocalist Sam Smith.

In sum, I don’t hate it, but I for sure didn’t fall in love with them.


John Wasson – Caravan

I will cut this one short, using Caravan’s cymbal strikes and brass instruments to analyze the treble region.

Starting in the upper mid-range and continuing into the lower or mid treble, the Wu Zetian is somewhat flat, which I really appreciate, as some weird spikes around this range turn the replays way too fatiguing for me, which isn’t the case.

There’s plenty of detail and enough energy, without me feeling the need to take a break. It still is somewhat wonky, a common characteristic about every planar treble, but nothing outrageous. It shows some sense of sharp transients, just enough to not sound blunt but still not as much as some others that feel extremely harsh to me in the treble region, like the primordial 7hz Timeless.

Now, if I have to pick on something, and I’ll do it, it has to be the mid to upper treble region, where the decay sometimes falls short on Caravan’s cymbal strikes.  Around the 5.5k hz area it just keeps diving, with some spike around 12k hertz, and falling down into oblivion. This was noticeable to me while critical listening and confirmed by a swine sweep.

It surely doesn’t affect the replay that much, but I had to note it, as I would prefer more air and a smidge more of detail up top.

Technical chops

Up to this point, I have touched on some of the technical characteristics of the Wu Zetian here and there, but I will now proceed to sum it up.

Wendy Marcini – The Plan

The dynamics on the Wu Zetian are average or above average for its price point, accompanied by the usual planar good sense of sheer detail

The stereoimaging is probably the best I’ve heard of any planar, so there’s that. It’s still an IEM, but it seems to be giving better use of its depth than its competition. It’s not ultra wide, and the imaging is not pinpoint, but it’s good enough with some sense of 3D, probably due to my HRTF.

The timbre on the WZ is the usual “planar timbre”, with fast decays and not as natural, but as always, whether you like it or not is a YMMV. This is usually provided by the ultra fast speed these kinds of drivers display, turning them into demi-gods for genres like metal or busy passages, especially when aligned with bass microdynamics like the ones Wu Zetian displays.

Last but not least, the separation and layering is on the mediocre side, probably affected by tonality and the need for more width/depth across the presentation.


For this section I will do a quick shootout between three of the current planar market favorites, plugged into Singxer SA-1 all at the same time, just switching and adjusting volume between them.

The lineup:

  • Raptgo Hook-X (using W01 tips)
  • LETSHUOER S12 (using Final E)
  • TANGZU Wu Zetian (using Final E)

The volume was matched at 77 db @ 440 hz and they are all using balanced 4.4mm cables. Both Hook-X and S12 take the same amount of power to reach this breakpoint, while the Wu Zetian is harder to drive, requiring more volume.


Hans Zimmer – Why So Serious? (Sub-bass drop around 3:25m)
ModelS12Wu ZetianHook-X

The best replay of the 3:25 claustrophobic drop goes, without any margin of doubt, to the Wu Zetian, a powerful combination allied with its tuning. It just feels powerful and overwhelming, as it should in that specific timestamp.

At the same time, the S12 follows suit on the rumble part, showing its drivers capacities but only losing to WZ due to tonality differences, with a more polite bass shelf.

The Hook-X is the opposite of the S12, having the desired elevation but falling shorter on rumble and extension compared to the other two.


Trentemøller – Chameleon (0:30m and onwards)

Regarding the bass, the three IEMs are planars, showing incredible speed. 

ModelS12Wu ZetianHook-X

Regarding the bass, the three IEMs are planars, showing incredible speed, making them suited for busy passages and high demanding genres. On microdynamics, the Wu Zetian tags along with the S12, with the last having a hair more but nothing worth mentioning imo, making them the best “mid-bassers” of the three, regarding impact and texture. The decisive factor between the two still falls under the tonality, with the WZ taking over the crown thanks to that.

The Hook-X follows the WZ tuning closely, which is great, but falls behind the other two regarding the subjective characteristics.


Hania Rani – Glass
ModelS12Wu ZetianHook-X

The tonality of the Wu Zetian is the most most recessed on these pianos, despite it’s nice transparency and detail, coming out as wishing for a smidge more. The note-weight is above the S12 with its bass shelf, but still below RAPTGO’s planar.

The Hook-X has by far the best tonality in the mid-range, only lacking the clarity and detail the other two have, more noticeable when listening closely to the separation between both hands playing, but by far replaying it the best. It is also the warmer of the three, with more note-weight and closer to reality.

The S12 is the most technical, analytical and transparent in the mid-range, and really good at that, but lacking some added body and still recessed, which would not be my pick for this genre.

Adele – Oh My God

My least favorite of the three, when regarding female vocals, has to be the S12. Its replay comes out as more gritty and aggressive, despite its superior clarity and detail on the voices. To my preferences, the LETSHUOER offer comes out as thinner and more analytical, lacking some body and the most recessed of the three.

The Hook-X has the smoothest female vocals and the better tuning, also supported by its extension into the treble that we will talk about shortly, but showing a clear step-down regarding these vocals’ detail quality. To note that it is, by far, the most forward presentation of the three.

The Wu Zetian is the middle of the road, showing a great compromise between the tuning and the details it shows, being my personal winner regarding this subject. It’s closer to neutral than to the Hook-X, but the details make up for it.

Dead South – In Hell I’ll be in Good company
ModelS12Wu ZetianHook-X

Once again, the LETSHUOER S12 comes out as the worst of the bunch, given its tonality. It’s the most recessed and thin out of the three and the male vocals just blend in between the rest of the track, despite its resolving power.

Coming close is the Wu Zetian, also showing a recession in the male vocals but not as much as the S12, as for that being a better replay but still not the best and not its stronger point.

The Hook-X is by far the best replay of male vocals between the three competitors. The elevation is there, coming out as north of neutral with great note weight and some bite to it, just falling short on these vocals’ clarity.


David Carroll – Hell’s Bells
ModelS12Wu ZetianHook-X

The Raptogo Hook-X has the most energy and feels somewhat crunchy, but has the bass to back it up and kind of plateaus after the pinna gain, so won’t feel as piercing as expected, at all.

The Wu Zetian, as mentioned before, has good treble but lacks extension, which slightly affects its decay.

The S12 is the worst replay of the three by having not only the energy but also the grainy feel, turning it into the most fatiguing IEM out of the three.


Yosi Horikawa – Bubbles
Polyphia – Playing God
ModelS12Wu ZetianHook-X
Resolving Power123

The Wu Zetian is my favorite pick regarding this section. While not being the most resolving, it has the best stage, mainly in its depth, with average imaging. It also shows better separation and layering, especially in the mid-range, compared to the other two. Regarding dynamics and resolving power, the WZ falls into the middle of the trio, closer to the S12 and distancing itself more from the Hook-X.

Hook-X has the best imaging and, due to its semi-open design, falls only very slightly short vs the WZ regarding stage size. Its width is barely the same, just with less depth, and for that I would take its competition regarding this topic, despite not having a clear winner between the two. Hook-X handicap has to be its resolving power and dynamics, especially when compared to the other two, that are slightly above.

The LETSHUOER S12 is the most diffuse and with a smaller stage, showing signs of congestion in placing instruments and separating them. It does take out its competition when we talk about dynamics and resolving power, being slightly ahead in those regards, giving a sense of more clarity and resolving power.

The bottom line

At this point, there is no doubt in my mind that every single planar offer on the market has built in trade-offs. I do not own a Timeless anymore, even though I had two, and I decided to leave Dioko out of this comparison for simplicity and because I think that’s a step below these three.

Either you pick S12, Hook-X or Wu Zetian, you can’t really go wrong, but you have to keep in mind what the trade-offs of each set are.

Sets like the LETSHUOER S12 or especially the 7hz Timeless come out as the most resolving and redefining the bracket bracket they sit on, but trade tuning (S12) or imaging chops (Timeless) to achieve those levels.

The Wu Zetian and the Hook-X trade some of that resolution for better tuning and stage presentation, but in different ways. 

The WZ keeps the V-shape style or, better it, enhances it, coming out with a better bass response and more tamed treble by losing a hair on the resolving power. 

The Hook-X follows the same trend, but boosts the mid-range as well, taking a toll on its resolving power and dynamics.

The Salnotes Dioko is a step below the others, mainly on the bass response that is pretty flat and soft, but undercutting the competition in price and focusing on a more balanced treble and mid response.

Speaking of price, I decided to leave it out of the spider graph, but it’s pretty obvious that the Wu Zetian and the S12 take the lead of price to performance, while the Hook-X and the Timeless are more expensive than these.

The verdict

Great performance, great accessories, mindfully priced and without compromising much, the Wu Zetian comes out as a winner, probably taking the crown as my favorite planar IEM up to this date.

Given that, I’ll cut it short and fully give it my full recommendation, without much else to add than if you are looking for a planar and you don’t mind a well done V-shaped sound, this is where you should start, in my opinion.

To TANGZU or Tforce, my congratulations. After not enjoying Yuan Li I must confess I was a skeptic, but you proved me wrong right from the first minute of listening to the Wu Zetian. Touché.

Thanks for reading!

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