Introduction

MOONDROP’s relentless march of budget-friendly product releases continues. We’ve covered 10 different IEMs from the Chinese brand thus far, of which nine have been under $200 and the majority under $50. This race to the bottom led to multiple releases I could not cover because seemingly everyone was doing the same, and yet I will give MOONDROP credit for effectively kickstarting competition with the CHU that came out last year. There was a lot of hype around it at launch owing to it being one of the best tuned sets, costing under $20, and even coming with fancy ear tips in the box. It had its shares of issues though, be it the non-detachable cable that itself wasn’t very nice to handle or the fatiguing upper mids and lower treble. The year since has seen several other competitors out and I suppose it was only a matter of time before MOONDROP decided to drop a second CHU on all of you.

The very first photo I saw of the teased CHU 2 confirmed a removable cable and that got people interested already. Then came news of a new driver system—still a single dynamic driver here—while retaining the smaller form factor that helps with fit and comfort of the original. MOONDROP also promised this was going to have more bass in a sign that the company was willing to accept the global market generally prefers more bass than its house target has, especially for IEMs targeting a more mainstream audience. Thanks to SHENZHENAUDIO for providing a review sample to TechPowerUp, as we begin our coverage with a look at the product specifications in the table below.

Packaging and Accessories

Packaging for the MOONDROP CHU 2 is relatively simple in that the box is smaller than for most other IEMs we’ve covered. It comes sealed in plastic and manages to still squeeze out female artwork on the front for those who care about it. The company and product names are on the front with a factory frequency response curve on the back to go with specifications in English and Mandarin. The box opens up to reveal the IEMs snugly packed in a thick foam sheet with machined cutouts and the various accessories are placed in a separate cardboard compartment underneath. These include a multi-language user guide, a QC card, a small card containing more such artwork, and the carry/storage case itself.

We see this is the exact same case that was provided with the MOONDROP Droplet and LAN IEMs, both of which are also among the more affordable sets on the market even if the CHU 2 is a decent chunk less expensive than either of them. I wasn’t a fan of the case back then and my thoughts have not changed since about the use of a button insert to close/open, which may not last long in good condition. There isn’t the most space inside either, so this is one of my least preferred IEM case designs. Inside is the cable itself as well as a plastic zip-lock bag that contains the included ear tips. MOONDROP is providing only silicone ear tips here—the exact same as with the LAN—and we get three pairs in sizes S/M/L as seen above. These are fairly generic ear tips at that so this will no doubt be disappointing to those who wanted to see the the same MOONDROP Spring Tips we saw come with the original Chu.

Closer Look

Once more we are left with scraps when it comes to any information being provided about the cable that the MOONDROP CHU 2 comes with. This is an unwelcome trend with the company’s releases in the last few months but it does seem to be a new cable not shared with the other MOONDROP IEMs I’ve reviewed. It begins with a right-angled 3.5 mm TRS single-ended connector headed to your source on a translucent plastic housing. The cable feels more pliable than I originally expected, but you will not mistake it for a premium cable given it can still get jumbled up in use and is slightly microphonic too. Perhaps going with a single sheathed strand is the reason for the noise, and the conductor inside appears to be silver-plated copper based on the color and design. The splitter is similarly simple and translucent as on the source connector housing and the other end has pre-formed ear hooks that terminate in two 0.78 mm 2-pin connectors that have plastic housings with a very subtle L/R marking to indicate the left and right channels, respectively. The various metal plugs are gold-plated for oxidation resistance.

The shells of the MOONDROP CHU 2 are very similar to that of the original MOONDROP CHU, down to the use of alloy cast zinc alloy cavities that form the shells. I appreciate the metal construction which can be more likely to withstand daily use compared to the usual acrylic resin, but then we see the same paint job done on the outside which I know by now won’t age well—just ask owners of the MOONDROP CHU/Aria/Aria Snow Edition/Starfield/STELLARIS/others. The design is even simpler this time with CHU being anglicized for 竹 (Zhú, meaning Bamboo) and the continuation of bamboo stalks being painted on the de-facto face plates. There are also L/R markings on the side of these relatively small shells where we also see the expected 2-pin cable connectors placed in an angled housing. Note also the two pieces of the shells that are glued together. More expensive IEMs tend to hide the gaps better than on the CHU 2, but it’s a non-issue as long as the glue does its job. Two vents on the inner side provide airflow to the acoustic chamber and minimize pressure build-up in the ears. The nozzle is a separate piece made of brass and angled in gently with a retaining lip at the end securing the ear tips in place. It is 6 mm at the widest spot, making aftermarket tip replacement harder than you might originally think. The outer part of the nozzle can be unscrewed to access the mesh filter placed inside to block contaminants from entering the acoustic chamber. If you find the filter gets clogged up, this makes it quite easy to replace with separately sold filters from retailers.

Connecting the cable is simple enough with the pre-molded ear hooks that go over the ears and L/R indicators helping identify what goes where. Push the 2-pin connectors into the IEM connectors as seen above until they fit in place via a friction fit. The other end then goes to the source of your choice wherein I had a good time pairing the CHU 2 with MOONDROP’s own sources including the MoonRiver 2. The cable does clash with the shells color wise but it’s admittedly low down the priority list for budget IEMs.

Fit and Audio Performance

Seen above is the right side of the MOONDROP CHU 2 installed in an anthropomorphic pinna that does well in showing my own experience with these. I have average-sized ears, and found the provided size M silicone tips to work fine, although you may want to look at aftermarket tips given the flange here is on the stiffer side, which could be a deterrant to fit inside smaller ear canals combined with the relatively large nozzle. On the other hand, I had an easier time fitting the CHU 2 than other IEMs with a slightly narrower nozzle owing to the design of this being lightly angled and not a conical design. If you do not get a good fit in the ear canals then the shells may likely jut out of the concha. The good news here is the shells are smaller than average so it’s not going to be an issue to fit them in the ears either. Another thing to be aware of is the vents are both on the inner side. The shells are sculpted to help avoid them being blocked up if in contact with the concha but do move them around to ensure you don’t suddenly hear them sounding way different from usual. The cable can also provide additional support points given the angular connection point helps direct the pre-formed ear hooks easily over and behind your ears, although a cable cinch would have been nice to further secure it. There’s no physical fatigue otherwise given the shells weigh ~6 g each, so no complaints on this front. I mentioned before how the CHU 2 is a single DD set and here we see the use of a 10 mm aluminium-magnesium composite diaphragm which is lightweight and quite rigid—read the equivalent section here to know more about why different material compositions can effect the performance of dynamic drivers. This makes the CHU 2 the first budget-friendly IEMs to use the otherwise expensive formulation, which in turn is associated with a polymer suspension and an ultra-thin copper-clad aluminium wire voice voil while being driven back and forth by strong N52 magnets. It results in a set of IEMs that is fairly average to drive given the low rated impedance of 18 Ω helps counter the relatively low sensitivity of 119 dB/Vrms (101 dB/mW).

Testing was done similar to all other IEMs, such as the recently reviewed MOONDROP Blessing 3. Seen above is the measured frequency response for both channels of the CHU 2 which can be inspected further here if interested. Channel balance is exceptional on this sample, keeping in mind this was one of the sets earmarked for reviewers but also that this is a budget set, and I’ll also re-affirm there was no burn-in effect felt or measured here. The overall tonality of the CHU 2 could be classified as mildly V-shaped leaning towards a brighter tonality. Some folks here might be surprised to see this coming from MOONDROP which prides itself on going with a strict VDSF target which leans neutral with a mild bass boost similar to my own target. I suppose this was inevitable given there are already a lot of such tuned IEMs, including from MOONDROP, so the CHU 2 can perhaps be interesting to those who want something different sounding. There’s nearly 10 dB of bass rise from 700 Hz going down with good extension all the way down to 20 Hz. The original CHU had a 5 dB shelf focused on the sub-bass that I added a 2 dB EQ filter on for some more meat in the mid-bass, so this was already very different while showing off what that new Al-Mg driver can do. It’s got decent slam and punch to attract electronic music fans as well as those who appreciate classic rock, although the minute you hear bass guitar strings or drums is when you will note the generally lackluster resolution throughout. The bass also bleeds into the mids to affect vocals to an extent while instrument separation can take a hit too.

It’s not the most analytical set thus, nor is it one I’d see anyone mixing music with. But the MOONDROP CHU 2 can still be fun, if not even engaging, as long as you don’t go in with magical expectations. Expect a relatively narrow soundstage with decent imaging in the front, for example. Timbre feels realistic but still with some plastic notes on drums and string instruments. Female vocals can potentially come off recessed compared to male ones, and the issues I had with the upper mids/lower treble being fatiguing on the CHU continue to be present here. The V-shaped tuning does help balance out the elevated 4-5 kHz region slightly to tone down sibilance, but it’s still not a set I’d particularly use for classical or jazz music. Pop or country music are more preferable, maybe also various metal genres.

The price range that the MOONDROP CHU 2 belongs to has become an exceedingly competitive one thanks to the original MOONDROP CHU. As such, it’s only fair that one of the comparisons be made to the predecessor unit. The CHU 2 is overall a better set in offering a detachable cable that’s also easier to work with, and I’d say it executes bass better in not just giving you more of it but also a punchier bass at that. Detail retrieval is about the same though, and the same could be said about most technical aspects. The treble response does feel more manageable though, but overall it’s a side grade in terms of tonality and what you prefer. I do feel that the Truthear HOLA and TangZu Wan’Er S.G., among other such entries, offer a better take on this bass-boosted sound signature though. The HOLA in particular also offers good bass but keeps cleaner mids and a much more controlled treble. There are also options from FiiO if you prefer a V-shaped or Harman-style sound but want to have an integrated microphone or prefer bullet-style IEMs. Go through your options and see what works best for your music library and comfort/preferences. If you decide the CHU 2 is for you, then it can be had for $18.99 from retailers such as SHENZHENAUDIO, as of the date of this article.