Today, Kurt reviews the Hidizs ST2 Pro Nebula, a new Kickstarter-funded dynamic driver IEM with an integrated DAC and headphone amplifier cable. Its MSRP is $89 with early bird pricing starting as low as $39.
Disclaimer: This sample was sent to me in exchange for our honest opinion. Headfonics is an independent website with no affiliate links or status. I thank Hidizs for their support.
To read more about Hidizs products we have previously reviewed on Headfonics click here. The Kickstarter campaign will start on Dec 19th, 2024.
Please note that this article follows our current scoring guidelines which you can read in more detail here.
Hidizs has carved a name for itself with its innovative and accessible audio gear at affordable prices such as the MP145. Now they’re back with a fresh entry-level offering via Kickstarter on Dec 19th called the ST2 Pro Nebula.
The $89 ST2 Pro Nebula is a dynamic driver IEM that combines a striking design with integrated DSP and amplification aimed at entry-level or budget portable audio enthusiasts.
Does the integrated USB DAC and amplification give the Nebula a distinct advantage over stalwarts at this price point such as the MOONDROP May? I find out how it performs and compares in my full review below.
Features
The Hidizs ST2 Pro Nebula features a 10mm dual magnetic circuit dynamic driver designed to deliver precise and natural sound. Its PU+PEEK composite diaphragm is both lightweight and durable, ensuring consistent and detailed audio reproduction.
The dual magnetic circuit design improves the driver’s efficiency and control, resulting in tighter bass, clearer mids, and improved treble control. This structure also helps reduce distortion and enhance the overall sound quality.
Hidizs has tuned the ST2 Pro Nebula with the Harman 2019 curve, ensuring a musical and enjoyable listening experience. The tuning highlights the driver’s capabilities, bringing out a bassier presentation.
Design
The Hidizs ST2 Pro Nebula features a resin body with no rough edges or sharp corners. Its faceplate showcases a reflective aluminum alloy etching of the Hidizs logo, giving it a premium and eye-catching finish.
Available in white transparent and black transparent options, the ST2 Pro Nebula lets users admire its internal drivers and wiring through its transparent shell. The cohesive silver coloring of the faceplate accents and nozzle adds a refined and modern aesthetic.
Weighing only 7g per earpiece without the cable, the ST2 Pro Nebula is lightweight and comfortable for prolonged use. Left and right markers, engraved as “Hidizs Nebula L” or “Hidizs Nebula R,” make identifying the correct earpiece a breeze.
One notable omission is the lack of vents for ear pressure reduction, which could cause minor discomfort for some users. Still, its lightweight build, intricate details, and transparent display make the ST2 Pro Nebula a striking and thoughtfully designed IEM.
Comfort & Isolation
The Hidizs ST2 Pro Nebula excels in comfort, thanks to its lightweight design that never feels intrusive during use. Even with the cable attached, the total weight is just 25 grams, ensuring an almost unnoticeable presence during extended listening sessions.
Its smooth and rounded body, paired with a flat faceplate, adds to its comfort, making it suitable for sleeping or commuting. The absence of sharp edges further enhances its wearability, allowing for prolonged use without irritation or discomfort.
Isolation is solid, aided by the lack of vents, which prevents external noise from interfering too much with your music. While it may not block out all sounds, it provides a decent level of noise isolation suitable for everyday use.
Tips
The Hidizs ST2 Pro Nebula comes with translucent white ear tips that are a step above your standard black silicone tips in both texture and fit.
These tips feel smooth to the touch, offering a grip that holds firmly in place without becoming sticky or causing itchiness during extended use.
Aside from comfort, the tips contribute to the overall sound quality by enhancing the treble. Their wide-bore design ensures optimal detail retrieval, balancing the ST2 Pro Nebula’s tuning for a bassier listening experience.
Stock Cable
The Hidizs ST2 Pro Nebula’s stock cable features an ESS ES9281AC PRO DAC chip built directly into the USB-C connector, delivering high-quality audio decoding. Its transparent housing showcases the circuit topology and gives it a premium touch to the design.
The cable supports PCM, DSD, and MQA decoding, with a powerful output of 70mW + 70mW at 32Ω. This ensures it can drive the ST2 Pro and other IEMs quite well, matching the performance of some dongle DACs.
An LED indicator provides real-time feedback on the audio format, glowing red for 4PCM 4.1-48kHz and blue for 88.2-384kHz signals. This simple yet practical feature enhances usability, making it easy for users to monitor the playback resolution.
The exterior is wrapped in durable textile yarn, available in black-blue or silver-gray colors. This design not only enhances the cable’s aesthetics but also improves its flexibility and durability for daily use.
Although the USB-C connector can get warm during extended listening sessions, it remains reliable and safe and not something that worries me much when using it connected to my smartphone.
For versatility, Hidizs offers 2-pin 0.78mm and MMCX connector options of which I have the 2-pin version here for review. The MMCX version, sold separately, includes the same ESS DAC chip, extending its capabilities to MMCX-compatible IEMs.
Packaging & Accessories
The Hidizs ST2 Pro Nebula offers a straightforward and satisfying unboxing experience. Opening the box, you’re greeted with the IEMs proudly displayed, showcasing their reflective faceplates.
A pull tab reveals an accessories pouch neatly tucked beneath the IEMs. Inside the pouch lies the cable, while below the pouch you’ll find the ear tips, a USB-A to USB-C adapter, and the warranty card.
Hidizs keeps the organization clean and functional, ensuring everything has its place. This thoughtful arrangement adds to the clean and tidy impression the ST2 Pro delivers right from the start.
Sound Impressions
The DSP of the Hidizs ST2 Pro Nebula introduces a fade-in at the start of every track, causing the first few seconds of the song to be missed. A manual restart of the track is needed to prevent this.
Bass
The Hidizs ST2 Pro Nebula’s bass performance is clearly geared toward bassheads, offering an abundance of sub-bass and mid-bass. Its punchy and powerful response makes for an engaging and energetic listening experience.
The rumble and slam are particularly satisfying, adding liveliness to its sound. Despite its focus on quantity, the bass retains enough detail to remain enjoyable without feeling overly exaggerated.
While impactful, the bass leans more toward power than refinement, which may leave texture, definition, and detail lacking for more discerning listeners. It doesn’t fully reach the deepest sub-bass regions, resulting in some loss of nuance and intricacy.
The ST2 Pro Nebula’s bass ensures a dominant low-end presence that drives its overall sound signature. However, its emphasis on bass prominence can sometimes overshadow other frequencies, making it less balanced.
Mids
The Hidizs ST2 Pro Nebula midrange provides a clean presentation, but the vocals are recessed. This allows the bass to dominate, pushing vocals to the background rather than making them the center of attention.
Timbre is acceptable but could feel more natural, as vocals sometimes lack weight and sound slightly thin. A scratchy quality is occasionally present, which detracts from the smoothness of the midrange performance.
The mids avoid muddiness and maintain a clear sound, but they don’t stand out in terms of warmth or richness. The presentation feels neutral and straightforward, offering clarity without adding much character.
Details and vocal nuances are not fully captured, leaving the mids sounding less expressive than they could be. While functional, they would benefit from more body and presence to balance better with the bass.
Treble
The Hidizs ST2 Pro Nebula’s treble offers above-average detail retrieval, ensuring fine elements in tracks are noticeable. Its energetic nature gives the highs a lively presence that adds brightness to the overall sound.
Sibilance control is acceptable, keeping harshness sometimes in check. However, the treble lacks the air that would add a sense of openness and extension to the upper frequencies.
Resolving ability is decent, allowing the treble to handle most tracks with a good amount of sparkle and brilliance. Overall, the overall tone leans bright, which might feel slightly aggressive for treble-sensitive listeners.
While the treble provides good detail and energy, it could benefit from more refinement and smoothness. Its brightness leaves room for improvement in creating a more natural and extended presentation.
Staging & Dynamics
The soundstage of the Hidizs ST2 Pro Nebula offers an average width, keeping the presentation confined. Depth is limited, resulting in more of an in-head listening experience without much layering or spatial dimension.
Imaging is also average, with instrument placement being clear enough but lacking precision. While it doesn’t excel in creating a holographic soundstage, it maintains a sense of order and avoids sounding chaotic.
Separation stands out as a positive, handling cluttered and busy tracks with ease. Instruments and vocals remain distinguishable, ensuring that the mix doesn’t collapse even in complex passages.
On the other hand, dynamics feel uneven, as the bass overpowers the mids and treble. This imbalance makes the overall presentation feel less cohesive, with the highs struggling to keep up with the more dominant low end.
Click on page 2 below for my recommended pairings and selected comparisons.
