HiBy x F.Audio Project ACE Review



HiBy, a company established in 2011, specializes in research, development, and sales of high-fidelity (Hi-Fi) portable audio products. These include digital audio players (DAPs), USB DACs with Bluetooth connectivity (BT DACs), and earphones.

HiBy has partnered with F.Audio, a company known for developing and manufacturing high-end earphones. F.Audio is led by Ken Lee, a music producer with a deep understanding of audio quality.

Together, HiBy and F.Audio have created the Project ACE, a new in-ear monitor (IEM) featuring a specially developed 12mm dynamic driver unit. This driver boasts a beryllium-plated diaphragm and a new Magnesium (Mg) & Lithium (Li) alloy dome. The driver is housed within F.Audio’s patented T.B.A.C. (Triple Built-in Acoustic Chamber) system.

The Project ACE is housed in a robust, pentagonal T6063 grade aluminum alloy shell with a moonlit-blue finish. The pentagonal shape embodies Project ACE’s commitment to five core principles of sound quality: balance, soundstage, dynamics, detail, and musicality.



I would like to thank HiBy for providing me the Project ACE IEM as review sample. I am not affiliated with HiBy beyond this review and these words reflect my true and unaltered, opinions about the product.


Price & Availability:

The suggested retail price (SRP) of the HiBy x F.Audio Project ACE In-Ear Monitors is US$ 249.00. More information’s can be found under the link below;


Package & Accessories:

The HiBy x F.Audio Project ACE arrived in a sleek, rectangular black box. The box was wrapped in a sleeve featuring the Project ACE branding on the top. The sleeve also had a golden design with one large round shape and several smaller ones, likely symbolizing the moon and stars.


Inside the box of the HiBy x F.Audio Project ACE are the following contents/accessories;

  • 1 pair x HiBy x F.Audio Project ACE In-Ear Monitors
  • 3 pairs x High Transparent Silicone Ear Tips
  • 3 pairs x Slow Rebound Memory Foam Ear Tips
  • 1 x Detachable Litz Type 5 Cable with 2-Pin Connectors and Modular Plug Design
  • 1 x 3.5mm SE 4Pin Headphone Plug Adapter
  • 1 x 4.4mm Balanced 4Pin Headphone Plug Adapter
  • 1 x Storage Case
  • 1 x Cleaning Brush
  • 1 x User Guide & Warranty



Design & Build Quality:

The HiBy x F.Audio Project ACE IEM offers a stylish design with a pentagonal-shaped shell crafted from T6063 aluminum alloy. This material is touted for its strength, plasticity, corrosion resistance, and lightweight properties, potentially contributing to a comfortable fit and long-lasting durability. The CNC machining, manual finishing, and anodization processes aim to create a sleek and luxurious aesthetic.

It features a 12mm dynamic driver with a beryllium-plated diaphragm that has a lightweight, rigid Magnesium (Mg) & Lithium (Li) alloy dome. This driver is housed within F.Audio’s T.B.A.C. (Triple Built-in Acoustic Chamber) system.

The HiBy x F.Audio Project ACE features a Triple Built-in Acoustic Chamber design, housing three distinct chambers for optimized sound. Chamber 1, designed specifically for the 12mm magnesium alloy dome driver, utilizes high-precision molds to ensure consistency and minimize distortion by effectively eliminating the instability and excessive airflow common in conventional drivers. Chamber 2 reinforces the driver’s rigidity with a metal structure to prevent unwanted resonance, while also regulating airflow through a rear air damper for a powerful and clear sound. Finally, Chamber 3 tackles ear canal pressure by releasing excess air while maintaining airflow, providing a constant supply of air to the driver and further enhancing sonic clarity.

The faceplate features the HiBy logo on the left monitor and the F.Audio brand logo on the right.

Both monitors have a nice gold-colored design element on their lower edges.

The inner surface of each monitor sports a short metal nozzle that does have a mesh on the top, while near the nozzle is one of the acoustic chambers.

On the top of the monitors is a 0.78mm diameter 2-Pin interface in order to connect the detachable cable.

At the rear side of each monitor shell is another acoustic chamber which is part of the Triple Built-in Acoustic Chamber design and a L / R marking.

The HiBy x F.Audio Project ACE comes with an detachable Litz Type5 coaxial cable, featuring a braided construction with three distinct materials. This design offers enhanced durability against pulling and some level of interference reduction for a cleaner audio signal. The cable cores are a mix of copper and silver-plated copper in a 1:1.6 ratio, specifically chosen to complement the Mg alloy and Be-plated diaphragm driver. This combination aims to achieve both the ideal transmission characteristics of each material and a reduction in internal resistance, ultimately contributing to improved sound separation.

The cable adopts standard 0.78mm connectors with a metal housing that hast L / R makings on its surface.

Utilizing HiBy’s newly designed 4PIN-Lock multi-functional adapter system, a single earphone cable with fastening design can easily be used with a variety of mainstream connectors such as 3.5mm single-ended and 4.4mm Balanced that are included inside the package. Additionally, HiBy plans to release a future adapter with a USB-C digital output and built-in DAC/amp, further expanding compatibility to digital audio players and smartphones.

The adaptors do have L profiled metal housing in a stylish design with the HiBy branding on top.

The HiBy x F.Audio Project ACE IEM combines a stylish pentagonal aluminum shell with a detachable Litz cable for durability and a premium look. Its T.B.A.C. chamber system and CNC machining ensure both audio fidelity and a well-crafted design.


Fit, Comfort & Isolation:

The monitor shape of the HiBy x F.Audio Project ACE offers a decent sense of comfort and durability with a unique blend of materials (T6063 aluminum alloy) and design. This translates to both long-lasting use and a remarkably lightweight feel, ideal for fatigue-free listening sessions. Furthermore, the Project Ace monitor shells shows an ergonomic inner shape that fits great to my ears with an average sized choncha.

The Project ACE earphones also provide passive noise isolation, effectively blocking out a good amount of ambient noise. This makes them suitable for use in moderately noisy environments like buses or trains.



The HiBy x F.Audio Project ACE The Project ACE shines with its low impedance of 32 ohms and high sensitivity of 115 dB. This combination makes them easy to drive, meaning they don’t require a powerful amplifier to sound good. This makes them ideal for use with a variety of sources like smartphones, tablets, or even USB DAC dongles.

However, during my testing, I noticed some sensitivity to background noise. To get the best performance, I recommend using the Project ACE with a source that has a clean output signal.


Technical Specifications:

  • Model                          : HIBY x F.Audio Project Ace
  • Drivers In Each Side  : 12mm Mg-Alloy & Be-plated Dynamic Driver
  • Impedance                  : 32 Ω
  • Frequency Response : 20-20,000Hz
  • Sensitivity                   : 115dB at 1kHz
  • THD                            : <1%
  • Max Input Power        : 100mW
  • Cable Length              : 1.25m
  • Cable Structure          : Litz Type5 Coaxial Cooper & Silver-plated Balanced Cable
  • Connector Interface    : 0.78mm Dual-pin / Detachable


Equipment’s used for this review:

  • IEM’s                          : HiBy x F.Audio Project ACE, Final Audio B2
  • DAP/DAC/AMP         : HiBy R6 Pro II, HiBy R4


Albums & Tracks used for this review:

  • Norah Jones – Come Away With Me (Flac 24bit/96kHz)
  • Adele – My Little Love (Deezer HiFi)
  • Sarah McLachlan – Angel (Flac 24bit/48kHz)
  • Sertap Erener – Aşk (Flac 16bit/44.1kHz)
  • Edith Piaf – Non Je Ne Regrette Rien (Flac 16bit/44.1kHz)
  • Diana Krall – So Wonderful (DSF)
  • Aretha Franklin – I Say A Little Payer (Flac 24bit/96kHz)
  • Michael Jackson – Billie Jean (Flac 24bit/96kHz)
  • George Michael – Don’t Let the Sun Go Down on Me (Flac 24bit/192kHz)
  • David Bowie – Heroes (Flac 24bit/192kHz)
  • Elton John – Rocket Man ((Flac 24bit/96kHz)
  • Barry White – Just The Way You Are (Flac 24bit/48kHz)
  • Isaac Hayes – Walk On By (Flac 16bit/44.1kHz)
  • Sting – Englishman in New York – (Flac 24bit/48kHz)
  • Eric Clapton – Wonderful Tonight (Flac 24bit/96kHz)
  • Dave Gahan – Kingdom (Tidal Hi-Fi)
  • Radiohead – Live in Berlin “Album” (Deezer HiFi)
  • Radiohead – Pyramid Song (Deezer HiFi)
  • U2 – Sunday Bloody Sunday (Flac 16bit/44.1kHz)
  • Muse – Hysteria (Flac 24bit/96kHz)
  • Red Hot Chili Peppers – Nobody Weird Like Me (Flac 24bit/48kHz)
  • Michael Jackson – Billie Jean (Flac 24bit/96kHz)
  • Bear McCreary’s – Valkyries (Deezer HiFi)
  • Bro Safari, UFO! – Drama (Deezer HiFi)
  • Armin Van Buuren – Vini Vici (Flac 16bit/44.1kHz)
  • Daft Punk – Instant Crush (Flac 24bit/96kHz)
  • Daft Punk – Doin’ it Right (Flac 24bit/96kHz)
  • Lorde – Royals (Flac 24bit/48kHz)
  • Massive Attack – Angel (Flac 24bit/48kHz)
  • Toutant – Rebirth (Deezer HiFi)
  • Gogo Penguin – Raven (Flac 24bit/192kHz)
  • Gogo Penguin – Murmuration (Flac 24bit/192kHz)
  • Portishead – It Could Be Sweet (Spotify)
  • Max Richter – On the Nature of Daylight (Flac 24bit/96kHz)
  • Charly Antolini – Duwadjuwandadu (Flac 24bit/192kHz)
  • Tchaikovsky – Symphony No. 5 (Flac 16bit/44.1kHz)
  • Ferit Odman – Look, Stop & Listen (Flac 24bit/192kHz)
  • Chopin – Nocturn No. 20 In C-Sharp Minor (Flac 16bit/44.1kHz)
  • Clair de Lune – Claude Debussy (Spotify)
  • Fazıl Say – Nazım Oratoryosu (Live) (Flac 16bit/44.1kHz)
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Deezer HiFi)
  • Miles Davis – So What (Deezer HiFi)
  • Otto Liebert& Luna Negra – The River (Flac 24bit/192kHz)
  • Lunatic Soul – The Passage (Flac 16bit/44.1kHz)
  • Deftones – My Own Summer (Shove it) (Flac 16bit/44.1kHz)
  • Metallica – Dyers Eve (Flac 24bit/96kHz)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Opeth – Windowpane (Flac 16bit/44.1kHz)
  • Megadeth – Sweating Bullets (Tidal Hi-Fi)
  • Rush – Tom Sawyer (Flac 16bit/44.1kHz)
  • Slayer – Angel of Death (Spotify)
  • Liquid Tension Experiment 2 – Acid Rain (Spotify)
  • Yosi Horikawa – Bubbles (Spotify)



The Sound:

The HiBy x F.Audio Project ACE is a single dynamic driver in-ear monitor (IEM) targeted towards audiophiles seeking a balanced and detailed sound signature with great sense of dynamic and musicality. . This review will analyze the ACE’s performance across the frequency spectrum, evaluating its bass response, midrange fidelity, and treble characteristics. The analysis will consider factors such as detail retrieval, neutrality, and potential coloration across each frequency range. Additionally, we’ll explore how the ACE performs in terms of soundstage presentation and dynamic range, providing a comprehensive picture of its technical capabilities.

This review is based on my listening experience after approximately 80 hours of burn-in for the HiBy Project ACE. The evaluation incorporates comparisons with sound sources including the HiBy R6 Pro II and HiBy R4 Digital Audio Players.



The HiBy x F.Audio Project ACE shows a strong and impactful bass response. Sub-bass frequencies are rendered with depth and texture, avoiding the common pitfall of muddiness. This translates to a satisfying rumble in the lows without obscuring the rest of the music. During testing with Daft Punk’s “Doin’ it Right,” the Project ACE delivered powerful bass notes that perfectly complemented the electronic elements of the track, without bleeding into the midrange and interfering with the vocals. Similarly, Lorde’s “Royals” showcased clear and defined kick drums alongside a well-controlled bass line, providing a solid foundation for the song’s rhythm.

The Project ACE exhibit excellent control in the mid-bass region, translating to tight and articulate bass lines. This characteristic was particularly evident when listening to Gogo Penguin’s “Raven,” where the Project ACE rendered the complex and intricate bass lines with precision, control and above average speed. This level of control in the mid-bass ensures that bass elements remain distinct and don’t overpower the overall soundscape.

The combination of powerful sub-bass and controlled mid-bass creates a truly immersive low-end experience, catering to audiophiles seeking a prominent and well-defined bass presence in their music.



The HiBy x F.Audio Project ACE shows itself with a well-balanced midrange presentation that prioritizes both neutrality and detail retrieval. F.Audio’s TBAC technology seems to deliver on its promises, offering a resolving and insightful listening experience.

The lower midrange is rendered with a natural and full-bodied character. This tuning particularly suits male vocals and bass-heavy instruments. George Michael’s vocals in “Don’t Let the Sun Go Down on Me” possess a rich tonality that complements the smooth, well-defined bassline. This characteristic carries over effectively to instrumental tracks as well, with each element in Charly Antolini’s “Duwadjuwandadu” – from the impactful drums to the distinct guitars – remaining clearly separated.

The Project ACE excels in its upper midrange response. While some might perceive this region as slightly warmer than the contemporary reference sound, it creates a more natural and organic presentation for vocals. Norah Jones’ breathy vocals in “Don’t Know Why” are rendered with effortless clarity, while the emotional nuances of Adele’s “My Little Love” are conveyed with impressive transparency.

Ultimately, the Project ACE’s midrange prowess establishes it as a versatile performer, well-suited for listeners who prioritize a clear, detailed, and tonally accurate soundscape, particularly for vocal-driven genres. This focus on faithful timbre reproduction ensures that instruments and voices are presented in a way that adheres to the recording’s sonic signature while remaining audibly pleasing.



The HiBy x F.Audio Project ACE prioritizes clarity and detail in its treble response. High frequencies are rendered with decent level of precision, revealing intricate nuances in cymbals, strings, and vocals. The resolute is an engaging and energetic listening experience. The mid-treble region enhances crispness and articulation, which was audible in complex musical passages. This is allowing for clear separation of instruments, evident in the intricate cymbal work of Metallica’s “Sad but True” or the complex guitar picking in Opeth’s “Windowpane.”

However, the treble presentation might not cater to all preferences. Some recordings with a naturally bright treble do feel a bit too lively due to a slight emphasis in the mid treble register (6 – 8 kHz region). This is subtly noticeable in the energetic electric guitar work of Rush’s “Tom Sawyer.” The upper treble area shows an audible roll-off that creates slightly warmer character. This is reducing the sense of air and making instruments like strings and percussions in genres like metal and orchestral music sound a bit grainy. However, this tuning makes the Project ACE also more suitable for longer listening periods.


Soundstage & Imaging:

The HiBy x F.Audio Project ACE prioritizes a detailed and holographic soundstage. Vocals and instruments are presented with clarity, occupying distinct positions within the overall soundscape. This approach allows for precise imaging, enabling listeners to accurately locate each sound source. The soundstage width may vary depending on source material, with some recordings offering a wider perceived space than others.



HiBy x F.Audio Project ACE versus Final Audio B2:

The HiBy x F.Audio Project ACE establishes its low-end dominance from the first note. Bass lines and deep electronic rumbles come through with precise power, ideal for genres that demand a rock-solid foundation. The Final Audio B2 offers some sense of low end, but with a subtler presence. While some might find this balanced for specific genres, the Project ACE delivers a more musical and entertaining low-end presentation with its excellent sense of depth.

The HiBy x F.Audio Project ACE Project ACE shines in the midrange, where most music lives. Vocals and instruments are produced with quite audible level of clarity and detail. Instruments from pianos to guitars retain their intricate detail, and powerful lead vocals retain their presence without any remarkable muddiness. The Final Audio B2’s midrange is competent, but vocals do sound slightly recessed for my taste compared to instruments, but this is not a real deal breaker.

The Project ACE’s treble adds a layer of crispness and detail especially in the low and mid-treble area. This approach might introduce a touch of brightness on certain recordings, but the overall effect is one of spaciousness and intricate detail retrieval. The Final Audio B2’s smoother treble is less fatiguing, but it can leave some recordings sounding slightly veiled compared to the Project ACE’s presence and clarity, especially for intricate acoustic guitar work or more complex classical pieces.

The HiBy x F.Audio Project ACE’s well-balanced sound translates into a wider and more immersive perceived soundstage. Instruments are precisely placed within the sonic image, creating a remarkable sense of spaciousness and depth. While the Final Audio B2’s soundstage is not cramped, it feels less holographic and slightly more intimate compared to the Project ACE.



The HiBy x F.Audio Project ACE IEM offers a well-balanced sound with impactful bass, detailed mids, and clear highs, all thanks to its innovative driver and acoustic chambers. Despite a slight emphasis in the treble and a rolled-off upper treble, it remains comfortable for extended listening sessions. With its stylish design, detachable cable, and ease of use, the Project ACE is a strong contender for audiophiles seeking a versatile and engaging listening experience.


Pros & Cons:

  • + Excellent Balance of Neutrality and Musicality
  • + Powerful and controlled bass
  • + Detailed and natural midrange
  • + Clear and energetic treble
  • + Stylish Design
  • + Rich Set of Accessories
  • + Modular Headphone Plug Design


  • – Sensitive to Background Noise
  • – Slightly Forward Lower Treble Tuning
  • – Trace of Grain in the Upper Treble


Thank you for the Read!


Original article