Introduction

2022 seems to be the year of planar IEMs and collaborations involving other audio reviewers, so it's perhaps fitting that I have two such instances being covered one after the other. The audio brand behind this particular offering is LETSHUOER, which impressed with the EJ07M tribrid IEMs and then again with the planar S12 set that was one of the first to capitalize of the success of this 14.x mm planar IEM formula, which began with the 7Hz Timeless last year. The LETSHUOER S12 was a commercial success and yet many found it to have more bias in the treble and often used a bass boost EQ filter on top.


Apparently doing a collaboration with another person these days is more about marketing than anything else as the LETSHUOER Z12 first came up a few weeks ago in blue/red colors and simply had a tiny ~2 dB bass boost over the original tuning. The other entity involved—Zeos from Z Reviews—also has his logo on the shells. I did not think that merited coverage owing to the minor changes however, soon after that batch was sold out, HiFiGo brought out a new version that was available in different colors of black and gold but also with a new modular cable from LETSHUOER. There was enough here to warrant a quick look article at least and so here we are, taking a look at the new LETSHUOER x Z Review Z12 planar IEMs which come in all black, all gold, or a random mix of the two as with my review sample provided kindly by HiFiGo.

Packaging and Accessories

I'll give LETSHUOER props for going beyond just a simple re-badging of the S12's product box here. While the base elements are the same in terms of the cardboard sleeve and internal box, the banderole is customized to this black/gold version with both colors generously applied. On the flip side, there are specks of what no doubt was supposed to look like gold dust randomly spread around the box but just look like normal dust, as I unknowingly tried to wipe them off when I first had the box in my hands. It comes wrapped in plastic and the outer sleeve has the collab mentioned directly, in addition to the product name and a render of the IEMs. The product specifications are on the back in multiple languages, with contact information for LETSHUOER also placed here. The inner box slides off to reveal larger branding taking up two sides and has an even weirder slogan on the other side. Open this to see a thick foam sheet with the two IEMs separately contained in snug cutouts for further protection, and a larger cutout below hosts a plastic clamshell box with some of the ear tips inside. We also get paperwork in the form of a multi-language guide going over the best usage of IEMs, a QC sticker, a card filled with QR codes for various different LETSHUOER web pages, and a warranty + after-sales support card.


The carry case is the exact same as what shipped with the S12 except with the newer LETSHUOER logo rather than the older Shuoer one, before the rebranding exercise took place. This is still one of the cheaper looking and feeling cases I have used, but is functional all the same with a relatively sturdy faux leather finish and a self-sealing zipper for some dust and spill resistance. It's also small enough to chuck inside your bag without taking up much space. Inside is the cable, a separate pouch containing the cable plugs, and the rest of the ear tips. LETSHUOER provides three types of ear tips—two silicone and one memory foam—with the Z12, and each comes in S/M/L sizes. The silicone tips differ in that one has a black bore and clear flange set and the other is less stiff while adopting an all-gray color scheme.

Closer Look

While LETSHUOER is mostly known for its catalog of in-ear monitors, a look at its Aliexpress page reveals it also sells standalone upgrade cables. The cable that comes with the newer Z12 IEMs takes the same S12 cable and then makes it modular to allow for users to have options of 2.5 mm balanced TRRS, 3.5 mm single-ended TRS, or 4.4 mm balanced TRRS plugs that simply are pushed into the receptacle on the cable and then head over to the source. The plugs are connected to aluminium housings given a gunmetal gray finish which lead to silver-plated copper conductors that come in two thick strands in a matching silver/gray color. There is the expected splitter a little over halfway down, and it is accompanied by a clear plastic cable cinch that barely works in practice. The other end consists of pre-formed, stiff ear hooks with plastic sheathing over the cables. Each of the two strands has a 0.78 mm 2-pin connector, with clear or red plastic inserts distinguishing the left and right channels respectively. It's not the best cable I've used—especially with the ear hooks and the slight microphonics in play—but the added modularity on the source side makes this a good update to the older cable on the S12.


The LETSHUOER x Z Review Z12 IEM use 5-axis CNC-machined aluminium alloy shells that are then anodized in the black or "gold" colors this particular version gets. I put gold in quotes here given some of the photos on the product page, as well as what your own mind may conjure when you think of gold, might lead you to think of the shiny yellow color as opposed to the more burnt orange here. Be aware of this and choose accordingly, given you have the option to go with all black, all gold, or a mix of the two. There's also the Z Review logo placed on the raised section with the chamfered edges, which helps accommodate the slightly inset 2-pin cable connectors on this otherwise highly rounded and smaller form factor shells. There is also venting right below with a single larger hole in the shell providing access to multiple smaller vents beneath. The model name, the serial number, and "L" and "R" markings for the left and right channels are etched into the top side, with another vent on the inner surface touching the concha. Since the LETSHUOER Z12 comes with no pre-installed ear tips, we get a good look at the integrated metal nozzle that is slightly shorter than average and has a retaining lip on the end, as well as the pre-installed filter preventing contaminants from entering the acoustic chamber.


Fitting the different ear tips is trivial, and that notch on the nozzle holds them in place. Seen above are the two types of silicone tips and the foam tips that come with the LETSHUOER Z12, all in size M and installed on these IEMs. Just make sure you go around the tips to ensure they are not in at an angle. Note that the widest point is ~5.5 mm at the notch, and the silicone tips were much simpler to fit compared to the foam ones. The gray bore tips are also slightly more tapered than the black bore ones, in addition to being softer. Try out the various different tips and sizes, and keep in mind that it's not necessary for both ear canals to have the best seal with the same set or size, either. Then connect the cable by identifying the matching channels and orienting the ear hooks around your ear and then pushing the pins into the female ends on the IEMs. The round housing on the cable side may not seem a great match with the rectangular IEM cutout, but I do like the overall aesthetics more than I originally thought. Now choose the source connector plug of your preference out of the 2.5/3.5/4.4 mm options, and you are good to go.

Fit and Audio Performance

Seen above is the right side of the LETSHUOER x Z Review Z12 installed in an anthropomorphic pinna that does well in showing my own experience with these. I have average-sized ears and found the size M black bore silicone tips to work best not just in terms of a good, secure fit with decent passive isolation, but the bore and flange combination making the sound signature more balanced. The good thing is that the Z12 shells themselves are quite small and ergonomically shaped, meaning they are quite likely to fit into most ears without issue. The gentle curves and smooth exterior also result in comfort over longer periods of time, and the metal chassis is cooling to the touch. On the flip side, if you are in a hot environment outdoors, it may get warm. The cable is also angled comfortably away with the pre-formed ear hook in mind, which had the cable provide another point of support for the IEMs. The shells weigh under average at ~6 g each and are not likely to cause physical fatigue, either. As for the driver used here, LETSHUOER is using the same 14.8 mm full-range planar magnetic driver from the S12 in the Z12, so I will direct you to this page for more on that. The Z12 is a typical planar set with an average impedance of 16 Ω paired with a relatively low sensitivity of 102 dB/mW, which makes these IEMs more power hungry than the typical set, but not enough to where you'd struggle when paired with a decent dongle. A portable DAC/amp will be plenty too and can give you some wireless connectivity options as well.


Testing was done similar to all other IEMs, such as the original LETSHUOER S12. Seen above is the measured frequency response for both channels of the LETSHUOER x Z Review Z12, which can be inspected further here if interested. I would classify this sound signature as V-shaped with elevated bass and treble, going further in this direction owing to the slight bass boost over the S12, as seen in the subsequent graph above. Indeed, there is very little to say here that I have not already done so on the full review of the S12, to where I will save time and words and mention that the bass boost somewhat helps balance out the hotter treble on the S12, which is still present here on the Z12. Channel matching was excellent here and a clear improvement over my first batch S12 that perhaps was LETSHUOER coming to grips with OEM drivers. Given a lot of customers of the S12 ended up putting a bass boost via EQ anyway I can see the appeal of the Z12 for new customers. It's not a perfect set, having the same tonality issues of the original and yet also has the same strengths that keep it in contention in 2022 even as more IEM offerings come about. Given the upgraded cable, the unique color combinations, and the slight bass boost on top, I can see this set carving out a worthy place for itself in the IEM market.

• The LETSHUOER x Z Review Z12 planar IEMs can be purchased for $169 in either color combination from HiFiGo on its web shop or Amazon store.
• The new, modular "Chimera" cable is also available for separate purchase at $49 from the HiFiGo web shop or its Amazon store too.
• HiFiGo was also kind enough to create a custom $10 discount code: HIFIGOZ12-VSG for use on the HiFiGo shop for the Z12. Please note that we do not get anything from sales of the unit and the discount was provided unsolicited.