Disclaimer:
After several months of waiting, the Hidizs ST2 Pro Nebula finally comes to life. Due to some unforeseen circumstances, the release of this product was postponed, but the wait was worth it.
Finally, an IEM arrives that integrates a particularly refined ESS chip into the cable and not the usual Realtek or Conexant.
The cable in this set is definitely the strongest and most interesting piece. Given its power and connector (which can also be requested in other versions), it is suitable for various HIDIZS models, especially the Mermaid series.
However, the review will still be 100% honest and in no way biased.
I’m not an audiophile; I’m just a guy that likes to test out different IEMs and DACs and spends a lot of time listening to music.
So I’m not going to use super technical words to review it, but I will do my best to describe it.
Tech Specs:
The specifications I report below are taken directly from the packaging.
- Dac Chip: ES9281AC PRO
- DSD Native: DSD64/128
- PCM Support: up to 384kHz/32bit
- MQA: Supported
- Sampling rate indicator: Yes
- Target H-2019 Curve
- Dynamic Driver: 10mm Dual magnetic Pu-peek
- Sensitivity: 108dB
- Impedance: 32 OHM
- Frequency Response: 20Hz-40kHz
- High-purity oxygen-free copper 2-strand wire (0.78mm 2-Pin)
- Customized Pouch/bag
- Hi-Res Certification
- Supe Early Bird Price: 39.00 USD – Early Bird Price – 49.00 USD – Full Price: 89.00 USD
- Launch Date: 19 December 2024
Packaging:
The packaging of the New Hidizs ST2 Pro Nebula is particularly simplified; the packaging immediately shows the ST2 Pro and underneath we find the Nebula Cable. The accessories included are:
- Transport bag
- Nebula Cable
- 3 pairs of tips
- A Type c to USB adapter
- Manual & Warranty card
The standard equipment is complete, and the adapter is always convenient to have included to be able to use the IEMs on all devices. As for the tips, the model seems very cheap to me. I don’t think they are the best tips that could be included.
Design/Build Quality:
In terms of build quality, the Hidizs ST2 Pro Nebula does not particularly stand out in my hands. The build quality is slightly superior to the Hidizs Galaxy. The general finishing is good but the substance is more or less the same. At the time of writing the review, I do not yet know the final price, but I hope it is in line with the materials used. As we can see, the faceplates have a gold-colored metal insert, and the shells are in smoked black plastic (perhaps resin). We have a ventilation hole near the connector (behind the driver) and one placed in the internal part near the nozzle (in front of the driver). Nozzle with a metallic finish similar to nozzles already seen on Hidizs products.
The most interesting part comes with the cable that integrates a nice DAC chip, namely, ES9281AC Pro with excellent performance. The connector with 2 visible windows allows you to see the various components inside. The cable is covered in fabric but remains very flexible and light. Microphone and button are present. Overall, it’s a very light set; no component feels heavy. Obviously, to the touch, it all feels a bit cheap.
However, this feeling does not have to be negative. It could be a choice to contain costs or to keep the set ultra light.
Initial Sound Impressions:
Somehow the Hidizs ST2 Pro Nebula is quite surprising, despite the single driver managing to express every frequency with a certain crispness. Although the target is the usual Harman 2019 this version is definitely brighter and closer to the mid-highs. For a single driver per side, the representation is absolutely very interesting, especially for the cleanliness and precise staging, even if not wide. Each sound has a millimetric placement in space, arriving at the eardrum extremely clearly. I can’t say if it is the cable or the IEM, but doing some tests I will surely be able to establish where the magic lies. Limited sub-bass but quite precise and dry bass.
Comfort/Fit:
The shape of the Hidizs ST2 Pro Nebula shells resembles that of the Mermaid series so the fit is almost unchanged. Their lightness does not cause heaviness on the ears. The cable is very flexible and comfortable. The Type C connector is compact enough not to be annoying.
Equipment used for testing above:
Device:
- OSX
- Poco M4 Pro
Software:
- Amazon Music UHD 24bit 96kHz (Both)
DAC:
- Built In
IEM Swap on Nebula:
The connector is a two-pin 0.78mm Hidizs format. It also fits other IEMs, but the greatest stability is found by staying with the same brand. The first IEM I had in front of my eyes was the Kefine Klean. In order not to go straight to a Hidizs MS3, I decided to try the Klean. Surprise surprise, the sound is very similar, with some points in favor of the Klean, which have gained sparkle. Let’s say that, as I expected, the cable does a lot of magic in the final result. The most obvious flaw in a similar product is the lack of an app to manage it.
Ok the Kefine Klean sound good but the connector inserts with little resistance.
Let’s try the Hidizs MS3 now; surprisingly, the connector grip is poor here too. In terms of sound, the low range is maintained much better than the previous IEMs. However, the sound is actually very similar, but the definition of the MS3 is on a whole other level. The Nebula cable, if sold at the right price, could really be a great product. I would just add a classic 0.78mm with a slightly higher grip.
Final sound impression:
The Hidizs ST2 Pro with the Nebula cable is a great match. But what gives even more joy is when you take the cable and use it with other IEMs, where you notice the true potential enclosed in a small ESS chip. The MS3 becomes truly absurd with an extremely resolute representation. But returning to the performance of the ST2 PRO as anticipated, it does not seem to have a single driver in your ears. Honestly, at first glance, the quality of the headphones does not seem to be very far from the MS1 Galaxy; perhaps the choice of materials should have been slightly different. What undoubtedly costs is the cable, and it is also what takes these IEMs to a higher level. I would like to point out that my evaluation is given with the SS20 tips. The stock ones did not guarantee me an optimal sealing.
Bass:
I would call it a dry and precise bass; the sub-bass is limited and the roll-off is very fast, but the whole thing is very natural and composed. In terms of purity of sound, there is no emphasis but a fairly linear response with a clean and short kick. Honestly, a more faithful representation in some tracks and others a little less, but if the track requires it, the potential is heard.
Mids:
Some have called them recesses, but I don’t think so. Perhaps graphically, they may seem so but to my ears, the voices come through clear and limpid, perhaps only second to the treble. The male and female voices are almost at the same level, silky, sinuous, and with the right tone and weight that enriches them, making them very real. Excellent also the whole set of musical instruments that accompany the voices on the same level.
Treble:
Treble very sparkling but never harsh or sibilant; a meticulous work of perfecting the DSP has made the treble extremely rich in macro and micro details (obviously not like on some hybrid IEMs), especially if you consider the single driver. A truly excellent result with trebles with an excellent extension that make listening full of air and energy. Obviously a bit of resolution is missing that can be achieved with other types of drivers.
Soundstage and Imaging:
As for the soundstage, it is not huge, but the DSP works very cleanly with a clear and precise image that allows a precise placement of sounds in a space. There are IEM Hidizs that obviously do better, but this remains, in my opinion, an excellent result.
Comparison:
A correct comparison should be made with products that have a DSP, but currently the only one that comes to mind is the Simgot EW300 DSP.
Vs. Simgot EW300 DSP
Simgot worked much more on the IEM than on the cable and produced an IEM with an incredible quality ratio. Honestly, the metal shell is really beautiful; the DSP is cheaper, at least in the chip used, but the result we can say is excellent. Simgot fills the lack of the DAC with a hybrid IEM that integrates what the chip cannot do. Very aggressive and interesting price.
Vs. Kefine Klean
Is a type C cable that integrates a DSP absolutely necessary? In my opinion, it is not absolutely mandatory that there is one; in fact, an IEM if it sounds good without tricks will sound good even years after having changed a thousand cables. The Kefine Klean is an economic example, together with the Delci, of how you can get an excellent product at a low price. Does the DSP make sense? Absolutely yes, but it should be sold above all as an accessory and perhaps integrate an app to make your own presets. The Klean sounds very good with the Nebula cable, but the connector does not make a grip that I would define as optimal. Evidently, the pins are slightly thinner than normal.
Conclusion:
In the meantime that I’m writing, I don’t know the final price yet. Honestly, I hope the product settles on a price under 100 USD. This is because if we take for example, the Simgot EW300 DSP, it has an extremely low price. Okay, they have a much cheaper type C cable but the IEM is much more elaborate. I think in a certain sense they can be compared to each other. I really like the cable, and I think it will be sold separately because they also wanted to send me an MMCX variant. The product promises to be 360° compatible with any product that supports audio on type C output (including new iPhones); the microphone in a call I made worked very well. In my opinion, the product is approved, but I would raise the construction quality and choice of materials a little.
Update 5/12/24 Price Reveal:
Now that I know the final price, many things make more sense. The launch price is set at $39 for the ST2 Pro + Nebula version, which is truly excellent. I had seen a price written as “XXX.00,” and I was somehow expecting a price above $100. Which honestly speaking would have been totally out of the market. The cable alone is priced at $36. So the ST2 Pro is indeed very cheap, as it seems. The price is certainly excellent but at least in my case, the 0.78mm pins of the Nebula have a little low resistance when inserted into other IEMs. The price itself is mostly made up of the cost of the ESS chip.
Could I abandon all else and focus just on the Hidizs ST2 PRO Nebula? Absolutely, because the quality is superb in my opinion; nevertheless, remember to change the eartips!
7.8/10
Pros:
- Good build quality
- Slightly improved comfort and fit
- Extraordinary Performance for single DD
- High-quality ESS chip
- Bright V-shaped sound—Harman 2019
- Good Macro & micro details
- Quite and accurate Wide Soundstage
- Pretty polished vocals
- Extra light and comfortable setup
- No need for cable upgrades
Cons:
- No App for DSP control or custom EQ
- Shell could be better
- Tips needs upgrade
- Treble spark are bright (Great for me but maybe not for you)
- Lack of subbass (subjetive)
- MQA is really needed?
