Disclaimer: NiceHCk sent the Smabat M2 for review. The M2 sports many of the same features of earlier versions of Smabat earbuds but with a modular design that allows tuning the earbuds to your preference. I have no financial interest in Smabat or NiceHCK, nor was I compensated in any fashion for this review. If you have an interest in purchasing the Smabat M2, check with NiceHCk via their aliexpress store.
Unboxing / Packaging:
The M2 Pro ships in a white lift top box with the Smabat name on the front in silver. The rear has a label with model number and basic specs. Lifting the top reveals the buds displayed in a card stock covered foam with cutouts for earbuds and tips and pockets for cable and tuning filters. Beneath the foam, the warranty card and manual rest in the bottom of the box. Kit is fairly standard with foams, rubber earpiece covers, cable, and filters. Foams do not include both donut models like previous releases and unlike earlier models, no case is provided. The other thing worth noting is some materials refer to 3 sets of tuning filters but only two were provided with this sample. It may be that additional filters become available at a later date but they were not included with the kit.
Like previous models, the St10s uses a 15.4mm driver so the earpieces are necessarily large to house the driver and overall shape is fairly consistent with earlier models. The earpiece itself is threaded onto the body and is removable via unscrewing it. The earpiece takes roughly one and one half turns to fully remove. Be careful as it twists the wires to the driver when removing the earpiece as the driver is housed in the forward section. Filters fit in the rear section and a tool is provided for removing them. One concern is that the filter lack a cutout for the wires to pass through so on top of twisting them repeatedly to change filters, you are in effect crimping them with the filter itself. Early renderings of the M2 Pro showed a wireless pad system connecting the front to the rear and I suspect the wired version was not the original intention but became necessary when the pad system could not be made reliable. In fairness with a screw on front, indexing those pads correctly every time would require very high precision machining and probably drive the cost through the roof so I understand why it was scrapped, but the current wired system needs some tweaks to be usable long term. Also, there are no spare o-rings provided and I broke one that fits between driver and rear shell almost immediately (1st filter change). The housings have the familiar gold outlined gray face and outer shell the driver housing being primarily black plastic. Fit and polish are good with no gaps around the mmcx connector and all edges slightly beveled for comfortable wear. Left and right are labeled on the spine of the housing leading to the mmcx connectors. MMCX connectors are good and tight (unlike my assessment of the original).
The Driver used in the M2 Pro is very similar to the 15.4 mm dynamic driver with a titanium coated peek diaphragm found in the recent ST10s Silver. Nominal impedance is listed at 40Ω with a sensitivity of 110dB/mW. In that respect it is a cross between ST10S silver and NCO models. The M2 Pro is usable from a cell phone or tablet and while using a higher powered source will give it a bit more low end punch at times, it doesn’t feel anywhere near as under-powered as the original St10 did when run from the same phone. The user has 3 tuning options as the M2 pro comes with 2 sets of filters or one can simply remove the filter altogether. One cannot use both filters at the same time as a 4th option as they will not fit within the housing simultaneously.
The cable provided with the M2 Pro is a 4 strand twist of silver plated copper and is a step above that provided with most previous models. It is a bit heavier and is designed for tip-up wear only as a result with pre-formed hooks at the northern ends. At the lower end, the cable uses a 3.5mm straight jack with a polished metal housing and a short strain relief. The splitter matches the jack in style and has a clear plastic chin slider above it which is well fitted and stays put when set. The top end as previously mentioned uses pre-formed hooks and polished metal housings for the mmcx connectors. No L/R markings are present on the housings, but a red ring at the base of the housing makes indexing straight forward.
The M2 Pro provides foams and vented rubber tips. I found that the rubber tips did help with keeping the M2 Pro from migrating during activity but found it to be the most signature changing of the options I tried and decided for sake of this review I would conduct all sound notes with none of the tips installed. Understand that your impressions will vary if you install tips and especially the rubber tips.
Remember that looking at the FR chart on an earbud is always misleading as buds are not meant to be sealed and almost every test rig is going to seal the face of the driver to a greater degree than actual wear. Notes below attempt to compare the two filters but not the M2 Pro without a filter as this is not really an intended use and it yields a very unnatural signature (See big spike in lower mids).
Sub-bass is very good with more presence than most earbuds. Having said that, it is still an un-sealed design and won’t compete with iems for those looking for slam and rumble. The Lows do bring enough to the party to feel solid and not bass-deficient. Mid-bass is roughly level with the sub-bass and has good clarity and detail with filter 1 and is a bit more pronounced and lifted with filter 2. I preferred filter 1 as the mid-bass became a bit looser and obstructive when using filter 2. Bass clarity is better with Filter 1 as well. Mid bass bleed is more prominent with filter 2 and gives the M2 a bit more warmth when that filter is in use at the expense of a bit of clarity in the lower mids.
As mentioned, mid-bass bleed can obstruct the lower mids depending on which filter is in use. Weight of the lower mids is a bit more with filter 2 but a bit cleaner and better presented with filter 1. As we move up, differences in the two filters become less. Filter 1 has a bit more mid/upper mid emphasis while filter 2 has more of an upper mid/lower treble emphasis. Again, this gives filter 1 a bit of an edge in my preferences, but those looking for a bit more vocal push may prefer filter 2. I found male vocals to be just slightly behind female with filter 1 and a full step behind with filter 2. Female vocals can get a bit harsh with poor recordings but for the most part were quite well voiced if the recording didn’t introduce stridency Strings lack a bit of weight but have reasonable clarity regardless of which filter is in use. Neither filter is great with strings, for that I prefer the ST10s.
Treble is very similar to previous Smabat tunings. A push early, then falling back a bit to prevent fatigue. The treble is polite and well detailed with some air but sparkle feels a bit limited. Extension is somewhat limited as the levels drop back considerably above about 9kHz and it is tough to find the absolute top end as a result. Snare has good attack but cymbals lack a little energy to be fully realistic.
Soundstage / Imaging:
Soundstage is roughly the same size as the other Smabat offerings wtih good depth and width and even some sense of height. Instrument separation is good (Better with filter 1) and makes seating the orchestra straight forward with no large gaps or odd placements. Imaging is good but, as with most earbuds, positions are a bit more general than exacting. Layering is good for a single driver with little tendency to thicken on complex tracks.
Thoughts / Conclusion:
I’m torn here. I like the sound with filter 1 and feel like this may be the best Smabat yet from that perspective especially considering price is less than 1/2 that of the ST10s Gold. The Downside is, I don’t trust it to hold up. Constantly twisting the wires to the driver is bound to cause problems eventually and if that doesn’t crimping them with the filter very well may. Having broken an 0-ring while removing the driver housing doesn’t lend confidence to the design either. I suspect this was not the intended design as mentioned in the build comments and I believe another generation of this product is needed to really fully develop the concept. Something about the M2 Pro just feels way more DIY than pro. If you intend to try the filters once and leave your preferred filter in them from then on, they may serve you quite well. If you are an inveterate tinkerer and intend to try different filter materials etc. I suspect the life span of the M2 Pro might be very short. Its a shame too, it sounds really nice.
Pros: Good lows, mid tuning options, polite treble
Cons: Serious build concerns and limited life-span due to design.