Hidizs has been rather active lately with their productions and they have some home runs this year especially with their planar IEM like the MP145 and the MP143. These products have been well received worldwide and had a successful Kickstarter campaign that saw hundreds of backers in just a span of a few months. The MP series will always be a product that has a special place in my heart due to their cause of protecting the world’s ocean by spreading awareness. Recently, they have been in the works again of creating something special and it has finally come to fruition, the ST2 Nebula, a 2 in 1 of a DSP with a Sabre chipset cable and a single dynamic driver earphones. The simplicity yet effectiveness of this setup is actually brilliant as the cable has a decent DAC simplifying the audio chain yet still preserving a high quality sound. Bella from Hidizs has kindly sent us a pair of the new ST2 Pro Nebula for an honest take and we thanked them for this opportunity.
Functions & Specifications
Before we start the review, here are the specifications of the Hidizs ST2 Pro Nebula;
The IEM;
- Driver: 10mm PU+PEEK dual magnetic driver
- Driver: 10mm PU+PEEK dual magnetic driver
- Driver: 10mm PU+PEEK dual magnetic driver
- Pin type: 0.78 2 pin/MMCX
- Sensitivity: 108dB
- Impedance: 32 Ohms
The cable:
- Decoding chip: ES9218AC PRO
- PCM sampling rate: 32-bit/384KHz
- Native DSD: 64/128
- Hi-Res audio support: Yes with 8X MQA support
- Distortion (THD+N): 0.0012%
- Signal-to-noise ratio (SNR): 118dB
- Dynamic range compression (DNR): 122dB
- Driving power (@32ohm): 70 mw + 70 mv
- Interface: 2 pin 0.78mm and MMCX
- Compatible devices: iPhone 15, 15 Pro, 15 Pro Max, iPhone 16, 16 Plus, Android phones, Mac, PC, and other USB Type-C devices
The Hidizs ST2 Pro can be purchased at Kickstarter and there is an early bird promotion, so act quick
ST2 PRO Nebula (Super Early Bird): $39.00 (Limited to 500 units)
ST2 PRO Nebula (Early Bird): $49.00
ST2 PRO Nebula USB-C DSP 0.78mm 2-pin/MMCX Earphone Cable (Early Bird): $36.00
Packaging & Accessories
As per usual of Hidizs latest flair, the package here came in an all paper box that actually has less plastics in them similar to the MP143. It does look like an entry type of packaging but it’s how the product performs that is what I am interested in. Inside we are greeted with the necessities like 3 pairs of soft silicone tips in various sizes, the DSP cable, a USB C to USB A adapter, some paperworks, a soft leather PU pouch and the head unit itself. Simple, straight to the point packaging.
Design
The design of the earphones head unit is good and it bears resemblance to the MS1 IEM from them as well and they are an entry level IEM with great value. It is made from molded resin and looks good but not as well made as a casted resin IEM. The ones with me are the black variations and they have a selection of grey with white cable and black with black and blue cable. The faceplate is adorned with an etched aluminum alloy with their branding. Well made product but they do look and feel like a budget earphones which they are as they only cost around 10 USD if you were to minus the cable cost.
Inside the earphones unit is a specialized 10mm dynamic driver that is customized by Hidizs and they have a polyurethane + polyetheretherketone (PU+PEEK) diaphragm with a Harman 2019 tuning that has a balanced sound with some bass boost in them.
The DSP cable here is a 2 core coaxial cable that has a high purity OFC core. It is a cotton sleeved cable that has a soft, supple touch to them with a pliable cable. They are on the thinner side but they do feel well made. There is a high quality microphone with a single button on it and it is suitable for any usage as the microphone quality is crystal clear. There will be a MMCX option in the future but for now they are releasing the 0.78mm option and will only be available in USB C termination.
Under the hood of the USB C body in my opinion is where the main dish of this product is. It is fitted with the venerable Sabre ES9281AC chipset and the way they integrate all this tech inside the small space is a feat of itself. It has DSD decoding capabilities, 8X MQA unfolding and a 32bit/384 kHz encoding. There is a small LED on 1 side which indicates the sample rate where red for 44.1khz to 48khz and blue for above 48khz and DSD. All this tech is visible as the USB C body has clear plastic windows on both sides. The 0.78mm pins are a flush type with an angular plug so wearing them cable down is possible but not recommended. The DAC does run warm after long usage but certainly not hot to the touch and they are very efficient in their power management as the power draw is barely noticeable.
The front nozzle of the earphones is made from metal with gold accents and they are fitted with metal mesh. The length here is good and they have a 6mm outer diameter with 5.5mm inner diameter at the body.
Gears Used for Comparisons
FiiO M17
Questyle M15
Faaeal KT4099
FiiO KA3
Rose Technics Maria 2
Toneking TO600
Moondrop Chaconne
Blur daBass
Faaeal Rosemary 2
Song List
Tone and Presentation
The presentation of the earphone itself is a mild V shaped Harman style sound that has a warm tone with a thick overall sound. It does have a rather balanced sound but with a twist of a boost in the sub-bass and mid-bass region producing a lively, energetic sound. They aren’t the most revealing set of earphones but a uber fun set for casual listening as they have a deep, organic overall sound without any hollowness present.
The DSP cable itself does have a neutral sound that is quite balanced with no humps or glare present and they possess a good transparent sound with a slightly clinical presentation. They match the earphones very well and together they produce a duo of fun yet technical sound.
Soundstage
Soundstage here is average at best but still capable of producing good width and height with a non boxy sound. Though being mediocre here, they do excel in producing an airy effect with their extension on both ends of the spectrum. Some of the soundstage is actually masked by the thick sound nature of the earphones but the headroom space here is still noticeable.
The cable itself actually possesses a decent width and height when used on other gears but still isn’t their main strength.
Separation and Timbre
Separation from these earphones is good but isn’t their main strength here and they are better with the ST2 Pro cable. Left and right are well presented in a good stereo manner but they do lack some width to be an excellent single dynamic driven set. Timbre here is organic, thick and smooth producing an inoffensive yet well balanced sound presentation that is suitable for an everyday carry for their non-fatigue sound signature.
As for the cable on itself, they do have great separation that actually gives a wide stereo dynamics rivalling some dedicated dongles. Timbre here is organic, slightly bright with a clean sound that actually matches with warm gears like the ST2 earphones quite well.
Drivability
At 32 ohms around 108dB sensitivity, the earphone unit is relatively easy to drive and doesn’t really need power to have sufficient volume and they are not a sensitive set of earphones that pick up noise easily. On the other hand, they aren’t suitable for monitoring purposes as the earphones don’t show minor flaws in recording and they work best with most recordings including streaming or even YouTube. As for source matching, a bright source matches them quite well with added clarity and details blending well with the warm, thick sound of the head unit of the ST2 Pro.
The cable itself is rated at 70 mw+70 mw at 32 ohms load which is mediocre on paper but they are actually quite powerful and capable of driving some of my open earbuds with sufficient volume. This cable itself is quite revealing on its own and it is able to show flaws in music quite well with a good increment in micro detail, punches above their asking price.
The Bass (Low)
The bass on the ST2 Pro is a boosted, warm bass response and they are the dominant overall sound in these earphones. They have adequate details and good clarity without sounding muddy but there is some minor bleed present especially when it is used with a normal 3.5mm cable. There is a healthy dose of mid-bass lift here giving an energetic, lively sound that sounded great with jazz, EDM, classicals and most modern pop genres. The bass amount here is actually suitable for bassheads that yearn for a strong bass presence and the high quality low end is just an extra perk. Resolution here is average with an acceptable vividness and a good transparent bass that is accurate but the texture is slightly loose. Sub-bass here is extended deep with a strong, clean rumble that blends well with the lifted mid-bass to prevent it from sounding hollow and they are authoritative without being overpowered. The overall bass has a decent amount of extension that gives a good amount of air that makes music sounds more spacious.
As for the DSP cable on its own, they are actually producing a neutral bass that has superb details and clarity with a balanced sound. They do have some mid-bass lift but it is minimal and the sub-bass has extension with a good amount of air added. Bass on the cable itself has good resolving sound and an accurate transparent sound that doesn’t alter much of the bass amount.
The Mids
Midrange that the ST2 Pro brings is a neutral midrange that has a lush and thick signature to them. The midrange here do have a well balanced sound with no major emphasis or lift in the region and that makes them a midrange that has an intimate sound with a good space between them with no scooped up, recessed midrange. Details here are good but aren’t great in the micro details when compared to some other entry earphones but they have decent macro details capabilities along with good clarity that has no veiling effect here. Resolution here is vivid and with a mild touch of coloration to give some sweetness to the sound and they have a decent transparency as the sound is clean and quite accurate. Vocals here aren’t their strength as they do lack some top end brilliance to make vocals, especially female ones sound lusher but they do have a great depth and body to them. The ST2 Pro earphones do perform better on instruments like the deeper, bassy, brassy type of instruments. Genres like EDM and classicals go superbly well here.
The DSP cable itself has a slightly forward sound that is neutral with a very mild warmth to them. The midrange here is leaning towards the higher range and has a good amount of brilliance present. They are a mildly bright sound and aren’t as bright as the usual Sabre sound. They have a detailed midrange with superb clarity along with an average resolving but a good transparency.
The Highs
The high range that the ST2 Pro brings here is an almost flat signature that has a smooth yet present type of highs. The high range here has a rather slow roll off which makes the highs slightly more extended producing an airy high range. The tone here isn’t bright per se but an almost dark-ish type of highs that is inoffensive, suitable for a long listening period without causing fatigue but those treble heads might be left wanting for more. Details and clarity here are good with a decent amount of crisp sparkle that gives some energy into the high range. Resolution here is okay but they do possess a great transparent sound that is accurate and sounds just as it is. Timbre here is breathy with no metallic sheen that is typical of a cheap dynamic drivers or balanced armature setup. Treble is tuned more towards a laid-back style and they are smooth to the ears free of any sibilance but they do lack some energy on certain genres like rock, acoustics and certain high staccato instruments as they lack top end brilliance.
As for the cable, they do have the DNA of a Sabre based chipset with a mild boost in their highs and they are slightly strong here but aren’t too overpowering. The usual Sabre hump is present but only on certain sources and it isn’t a deal breaker here. Details, clarity and resolution is great along with a decent transparency.
Comparisons
VS CCZ DC02 Solo
The DC02 Solo is the most recent release from CCZ and they are trying to make a comeback in the budget segment in 2024. They are priced half at the asking price of the ST2 Pro Nebula but the ST2 Pro does have a better package mainly for their awesome cable and they are packaged more complete with an extra pouch and a better unboxing experience. Build of the earphones is similar but the ST2 Pro quality does look and feel better. Both have a similar V shaped sound but the ST2 Pro isn’t as recessed on the midrange.
The High region on DC02 is brighter and they are more present than the slightly laid-back highs of the ST2. Details and clarity both are on par with each other but sparkle is better and more natural than the DC02 that has some metallic sheen on them. The ST2 Pro does resolve better here with better transparency but they can be shouty at times.
Midrange of the ST2 Pro is thicker with better clarity but lushness is better on the DC02. Mids on the ST2 Pro are not as recessed as the DC02. Details and clarity is similar while resolution is better on ST2 Pro. ST2 Pro does have the strength in their overall midrange technicalities while DC02 is more focused on mainstream genres by giving the attention to the bass and treble.
Bass on the DC02 has the edge by sounding fuller and has a better impact in their sub-bass along with deeper extension but they do sound a little overwhelming at times and have more bleed present. ST2 Pro bass does sound leaner but still strong in quantity with a more balanced amount.
Soundstage on the ST2 Pro is wider and taller along but airiness on both are quite similar.
VS KZ ZS12 Pro X
The ZS12 Pro X is one of their most recent hybrid earphones from the budget king, KZ. They are equipped with a single dynamic and 5 balanced armatures with an all zinc alloy metal body which gives them the edge in the built quality region. Both are priced similarly but again, the inclusion of the DSP DAC cable is a cherry on top for the ST2 Pro. KZ unboxing experience is known for being cheap and lacklustre, so the package of the ST2 Pro does take the cake here.
Highs on the ZS12 Pro X does have the quantity with a faster, crisper highs that derived from balanced armatures setup. The highs on the ST2 do sound more natural with better transparency but the ZS12 Pro X highs have better resolution. ST2 high does sound smoother and more laid-back while the ZS12 Pro X has a faster attack with more energy but they do exhibit a metallic sheen from the BA drivers. Treble extension on the ZS12 Pro X is better but they might be a little harsh.
Mids on the ST2 Pro are thicker and lusher while ZS12 Pro X has a more resolving midrange. Details and clarity here is better on the ZS12 Pro X but in a small margin. Instruments sounded fuller on the ST2 Pro but the vocals sounded more energetic with the ZS12 Pro X for their extra upper mids brilliance. The ST2 Pro does have better transparency versus the slightly clinical sound on the ZS12 Pro X.
Bass on the ST2 Pro has better impact with a better extended sub-bass. The bass amount does sound bigger on the ST2 Pro. Details and clarity here are similar here. The ZS12 Pro X bass does have better air with a more accurate amount as well as a tighter bass.
Soundstage of the ZS12 Pro X is wider and airier but height is similar.
ST2 Pro Cable comparison
Dunu DTC100
The DTC100 from Dunu is one of the first dongles from Dunu and they are equipped with a similar Sabre chipset but an older model which is the ES9118EC. They don’t have MQA support but have DSD support with lower driving power of 25 mv versus 70 mv from the ST Pro cable. The price of the DTC100 cost almost the same as the whole ST2 Pro Nebula package itself. The matching here is being done with 3rd party 3.5mm cable.
Highs are brighter and have a slight harshness when compared with the ST2 Pro cable. They do sound clearer but details are the same. The Sabre hump here is more noticeable with the DTC100.
Midrange has better resolution while details and clarity is better on the ST2 Pro. Midrange has a more forward sound on the DTC100 while the ST2 Pro does sound thicker and more lush. Resolution and transparency does go to the ST Pro cable.
Bass is slightly punchier on the DTC100 but quantity remains the same. Sub-bass has a better extension with better mid bass lift on the ST2 Pro cable. Details and clarity is better on the DTC100 by a small margin.
Soundstage on both is similar with average width and height.
Who Is It For?
The ST2 Nebula is for those users who want simplicity without sacrificing sound quality, as they are a well implemented Sabre chipset. The earphones itself is actually quite decent with a mild V shaped sound that is suitable for modern genres but not so much for critical listeners. The cable itself has a wide application and I do find it is perfect for gaming, movies and even calls as they have near 0 latency due to the direct USB C without any extra connectors in between. The price is budget friendly and suitable for beginners as well as long time users who yearn for portability.
Final words
Well Hidizs has made something unique and it is an idea that makes sense for an ultra portable audiophile set that possesses a high quality decoding and a decent earphone to complete the set. The price here is spot on and with their early bird promotion, it is actually a steal especially with their cable. The cable for me is the main attraction here as it has all the decoding you will ever need like MQA and DSD. It has a well implemented Sabre chipset with a nice looking fabric cable suitable for an everyday carry. The earphones itself is actually quite mediocre but users can opt to buy the cable only with a slightly lower price which is great. A superb value indeed this time from Hidizs. Kudos!
I would rate this product a solid 4 and a half stars out of 5 stars for this amazing combo product.
Pros
Earphones
- Decent built with great fit
- Easy to drive
- Harman tuned with a boosted bass
- Warm, bassy inoffensive sound
- Decent resolution
- Smooth high range
- Thick, forward mids
- Strong, authoritative bass
- Deep sub-bass extension
Cable
- Beautiful design with soft fabric sleeve
- Accurate sound with good technicalities
- Portability
- Balanced tone with a slightly bright sound
- Good soundstage width
- Great details and clarity
- Zero background noise
- Neutral bass and midrange
- Strong yet inoffensive high range
- Decent power efficiency, low power draw
- Adequate driving power for efficient gears
- Cable microphone quality
- MQA, DSD full support
Cons
Earphones
- High range lack crispness
- Soundstage a tad narrow
- Tone can be a little too warm and bassy
- Mediocre details retrieval
- Some coloration on the midrange
- Highs lack crispness
- Not a clinical performer
Cable
- No gain settings(nitpick)
- Cable is on the thinner sider
- Angled 2 pin that can only be used on over ear earphones
- Slightly dry sound
- Mild peak on high range
