EarAcoustic SPA-Hi End Ultra Review

 

Introduction:

The EarAcoustic SPA-Hi End Ultra represents a bold evolution for a brand that has transitioned from its TFZ roots to establish itself in the audiophile arena. This premium In-Ear Monitor features a single 11.4mm dynamic driver with a titanium gold ball top and silicon crystal edge composite diaphragm, complemented by a dual magnetic circuit and dual chamber design. Housed in a zinc alloy shell with mirror silver electroplating and CNC post-treatment, the SPA-Hi End Ultra combines aesthetic sophistication with acoustic ambition.

Let’s take a deeper look at the packaging, design, and sonic performance of the EarAcoustic SPA-Hi End Ultra.

 

Disclaimer:

would like to thank EarAcoustic Audio for providing the SPA-Hi End Ultra for review purposes. I am not affiliated with EarAcoustic Audio beyond this review, and the opinions expressed here are my honest and unbiased impressions of the product.

 

Price & Availability:

The MSRP price for the EarAcoustic Audio SPA-Hi End Ultrais 189,90 US$. More information’s can be found under the link below;

• EarAcoustic Audio SPA-Hi End Ultra

  

Box Design & Unboxing Experience:

The EarAcoustic SPA-Hi End Ultra arrives in a sleek, minimalist package that sets a sophisticated tone for the unboxing experience. The outer box is a square black design, exuding simplicity and elegance.

Inside the box are the following items/accessories;

• 1 x pair of EarAcoustic SPA-Hi End Ultra IEMs
• 1 x Litz cable made of oxygen-free copper and silver-plated strands
• 6 x pairs of ear tips
• 1 x Zipper Case
• 1x User Manual
• 1x SPA Lucky Bracelet (gift), featuring a black cord with a small pendant

 

Design, Build Quality and Fit:

When I first picked up the SPA-Hi End Ultra, the zinc alloy shells immediately caught my attention due to their weight and presence. Each earpiece weighs 14 grams, providing a solid, premium feel that is substantial yet comfortable for extended wear. The shells feature a mirror silver electroplating finish with CNC post-treatment, creating a highly reflective surface. Light hitting the shells, whether from a window or a desk lamp, produces a shimmering effect that gives them a polished, almost liquid-like appearance. However, this glossy finish attracts fingerprints easily and over time, the finish may also develop fine scratches without careful handling. The faceplate stands out as the centerpiece of the design.

Coated in crystalline resin with a diamond-patterned texture, it refracts light to create a prismatic display of colors, shifting from soft blues to warm golds depending on the angle. Tilting the IEMs under light feels like peering into a miniature kaleidoscope, with each facet adding depth and visual intrigue. This faceplate elevates the IEMs beyond mere audio equipment, giving them a jewelry-like quality that distinguishes them from more utilitarian designs I have encountered.

For ease of use, the IEMs include clear labeling. Small, engraved “L” and “R” markings appear on the inner side of each shell, alongside the words “Right Monitor” and “Left Monitor.” The minimalist engravings blend into the sleek design, though they can be hard to read in low light. After a short adjustment period, identifying and wearing the correct earpiece became intuitive.

The 0.78mm 2-pin connectors, located at the top of each monitor, offer a sturdy and reliable connection point. Attaching the cable produces a firm click, and I noticed no looseness or instability. The top placement keeps the cable unobtrusive during wear, which proved comfortable even during long listening sessions.

The sound nozzle includes a metal mesh to block debris and is fixed, unlike some IEMs with interchangeable nozzles for tuning flexibility. The nozzle’s slight angle and sturdy build ensured a secure fit in my ears, particularly with the included silicone tips.  The mesh held up well, showing no signs of clogging even after prolonged use.

An acoustic opening on the rear of each shell features a finely woven metallic mesh. This mesh, nearly indistinguishable from the mirror silver finish, supports airflow to enhance acoustic performance. Its subtle integration maintains the IEMs’ streamlined aesthetic, which I found to be a refined touch.

The build quality impresses with its robust construction. My only concern, beyond smudges, is that the mirror silver coating may not maintain its pristine look as well as a matte or brushed finish over time.

 

Detachable Cable: 

The SPA-Hi End Ultra comes with a high-definition coaxial bundled Litz cable, constructed from oxygen-free copper and silver-plated strands. The cable feels soft and flexible in hand, avoiding the stiffness common in lower-quality cables. It resists tangling effectively. Whether I stored the IEMs in a pocket or loosely coiled them in a case, the cable remained knot-free.

The silver-plated strands aim to minimize high-frequency signal loss, and while I cannot verify the technical specifics, the audio transmission remained consistent and clear throughout my listening. The cable uses 0.78mm 2-pin connectors that align flush with the IEMs, ensuring a secure and visually cohesive connection.

I tested compatibility by swapping the cable with aftermarket options, and the connectors handled the process without wear or loosening.

The Y-split and plug also feel robust enough for daily handling.

The cable terminates in a 3.5mm single-ended plug, suitable for most portable devices but incompatible with balanced setups. Users preferring 2.5mm or 4.4mm balanced connections will need a separate cable, which feels like a minor oversight for a premium product. Aesthetically, the cable complements the IEMs’ design. Its smooth, slightly translucent sheath and metallic accents at the connectors harmonize with the mirror silver shells. The cable’s durability stood out during weeks of regular use, with no fraying or weak points.

Overall, the cable matches the IEMs’ quality and design, though the lack of a balanced termination option limits its versatility for some users.

 

Driver Configuration:

The SPA-Hi End Ultra is powered by an 11.4mm dynamic driver, featuring a titanium gold ball top and silicon crystal edge composite diaphragm. This driver is housed in a dual magnetic circuit and dual chamber structure, driven by an N52 high-power magnet. The design delivers a wide frequency response (5Hz–40kHz) and high sensitivity (110dB), with a high-rigidity diaphragm ensuring a smooth frequency response.

The dual chamber configuration minimizes resonance, enhancing clarity and dynamic range.This driver setup prioritizes analytical precision and bold dynamics, aiming to deliver a vibrant yet detailed sound profile. The use of advanced materials and acoustic engineering underscores the IEM’s high-fidelity ambitions.

 

Fit, Comfort & Isolation:

The SPA-Hi End Ultra offers a comfortable fit, with its ergonomic shell design aligning well with the ear’s contours. The zinc alloy construction adds weight, but the contoured shape ensures stability for most users. For average-sized ears, the IEMs remain comfortable during extended sessions, though smaller ears may require experimentation with ear tips to avoid fatigue. The SPA-Hi End Ultra offers adequate passive isolation, effectively reducing a noticeable amount of ambient noise. This allows for a more focused listening experience in various environments, making it easier to discern the finer details within the audio.

 

Pairing & Drivability:

With an impedance of 26Ω and a sensitivity of 110dB, the SPA-Hi End Ultra is highly efficient, making it easy to drive with smartphones, tablets, or low-power DACs. It pairs effectively with devices like the Sony WM1ZM2 and FiiO M23 (DAP) or iBasso Nunchaku (dongle), delivering consistent performance across sources. The IEM scales well with higher-end setups, where its dynamic sound profile benefits from warmer, high-resolution sources, enhancing detail and impact.

 

Technical Specifications:

• Model: SPA-Hi End Ultra
• Driver: 11.4mm Titanium Gold Ball Top + Silicon Crystal Edge Composite Diaphragm, Dual Magnetic Circuit, Dual Chamber Dynamic Driver
• Sensitivity: 110dB (@1kHz)
• Impedance: 26Ω (@1kHz)
• Frequency Response: 5Hz–40kHz
• THD: <0.5% (@1kHz)
• Cable Jack: 0.78mm 2-pin, 3.5mm single-ended

 

Sources used for this review:

• IEM’s              : EarAcoustic Audio SPA-Hi End Ultra, Moondrop Kadenz
• DAP/DAC’s   : Sony WM1ZM2, FiiO M23, iBasso Nunachaku

 

Albums & tracks used for this review:

• Norah Jones – Come Away With Me (Flac 24bit/96kHz)
• Norah Jones – Don’t Know Why (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)
• Stevie Ray Vaughan – Riviera Paradise (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’s – Tom Sawyer (Flac 16bit/44.1kHz)
• Slayer – Angel of Death (Spotify)
• Liquid Tension Experiment 2 – Acid Rain (Spotify)
• Yosi Horikawa – Bubbles (Spotify)

 

The Sound:

After spending considerable time with the EarAcoustic Audio SPA-Hi End Ultra, I found its sound profile to be lively and engaging, characterized by a mildly V-shaped tuning that emphasizes impactful bass and bright treble, with a slightly less prominent midrange. This sound signature delivers an energetic listening experience, particularly well-suited for genres such as rock, pop, electronic, and jazz. Following a 50-hour burn-in period, using the provided silicone ear tips and stock cable, the IEMs revealed a bold yet detailed character that feels competitive in the sub-$200 price range. The sound combines punchy low frequencies, clear mids, and airy highs, complemented by a wide soundstage and accurate imaging.

This review reflects my firsthand impressions after 50 hours of burn-in, using the stock silicone ear tips and cable. I tested the IEMs with sources including the Sony WM1ZM2, FiiO M23 Digital Audio Player, and iBasso Nunchaku USB DAC/AMP dongle. Below, I detail the performance across bass, midrange, treble, and technical aspects, offering a thorough breakdown of my experience.

 

Bass:

The bass performance of the SPA-Hi End Ultra stands out as a core strength. Its 11.4mm dynamic driver produces deep, resonant low frequencies with a strong focus on subbass. Listening to tracks like Armin Van Buuren’s collaboration with Vini Vici, I felt the pulsating basslines drive the rhythm with a visceral intensity that added weight to the music. Kick drums in Daft Punk’s “Instant Crush” landed with a clear, satisfying impact, maintaining clarity without excessive warmth. The subbass decay feels controlled, preventing low frequencies from lingering too long. However, in bass-heavy tracks, I noticed a slight tendency for the subbass to blend into the lower midrange, adding warmth but occasionally reducing separation between instruments.

In the midbass range, the IEMs deliver a punchy and textured response. Tracks like Gogo Penguin’s “Raven” showcased the midbass’s ability to render intricate basslines with both speed and fullness, allowing complex rhythms to stand out clearly. In Red Hot Chili Peppers’ “Nobody Weird Like Me,” the interplay between bass guitars and drums felt articulate, with the midbass avoiding muddiness even in demanding passages. That said, in tracks with rapid dynamic shifts, such as Tchaikovsky’s “Symphony No. 5,” the bass could feel slightly less precise, where subtle transitions would benefit from tighter control. This minor limitation seems reasonable given the price point.

 

Midrange:

The midrange of the SPA-Hi End Ultra is clear and expressive, though its V-shaped tuning results in a slightly recessed presence compared to the bass and treble. The lower midrange adds warmth and body to male vocals and instruments like acoustic guitars and cellos. Listening to George Michael’s “Don’t Let the Sun Go Down on Me” and David Bowie’s “Heroes,” I appreciated the richness that made male vocals feel full and emotive. However, in busier tracks like Muse’s “Hysteria,” the prominent bass and treble occasionally overshadowed the mids, making vocals and instruments feel less forward. Instruments such as pianos and violins in Fazıl Say’s “Nazım Oratoryosu” retained good texture but lacked the intimacy of more mid-centric IEMs.

The upper midrange performs smoothly, delivering detail without harshness. Female vocals in tracks like Sertab Erener’s “Aşk” and Edith Piaf’s “Non, Je Ne Regrette Rien” sounded delicate, with vocal nuances clearly conveyed. However, the recessed mids placed vocals slightly behind the instrumentation, which was noticeable in Sarah McLachlan’s “Angel,” where the emotional weight of the vocals remained strong but less prominent than in mid-forward IEMs. This tuning prioritizes comfort for long listening sessions, avoiding fatigue, but it sacrifices some vocal presence compared to competitors with a more balanced midrange.

 

Treble:

The treble performance of the SPA-Hi End Ultra impressed me with its clarity and airiness, offering a level of detail that competes well in its class. High-frequency instruments like cymbals, hi-hats, and flutes sounded precise. In Metallica’s “Sad but True,” cymbal crashes had a crisp, natural decay, while Miles Davis’s “So What” highlighted the trumpet’s high notes with a sparkling texture that added openness to the sound. The treble carries a touch of brightness that enhances detail retrieval, as heard in Ottmar Liebert & Luna Negra’s “The River,” where string plucks stood out with clarity. Importantly, the tuning avoids sibilance, making it comfortable for extended listening across genres like jazz and classical.

In tracks with prominent high frequencies, such as Michael Jackson’s “Billie Jean,” the treble could feel slightly intense, with hi-hats and synths standing out prominently. For treble-sensitive listeners, this brightness might be noticeable, though it stayed within tolerable limits during my sessions. The upper treble extends effectively, contributing to a sense of airiness that elevates the listening experience, particularly for genres that benefit from an open sound.

 

Soundstage & Imaging:

The SPA-Hi End Ultra creates a spacious soundstage with notable width and respectable depth, delivering an immersive experience. Listening to Yosi Horikawa’s “Bubbles,” I could clearly distinguish instruments and effects placed in a three-dimensional space, with excellent separation between elements. In orchestral pieces like Tchaikovsky’s “Symphony No. 5,” the soundstage conveyed a sense of scale, though it fell short of the layered depth found in more expensive IEMs. The imaging proved precise, enabling accurate localization of instruments. In Red Hot Chili Peppers’ “Nobody Weird Like Me,” guitar riffs and drum hits occupied distinct positions, enhancing the track’s energy.

The open and airy presentation particularly enhanced live performances and electronic music, where a wide soundstage amplified the sense of space. Overall, the soundstage and imaging contribute significantly to the IEMs’ engaging and dynamic sound profile.

 

Comparison:

EarAcoutic SPA-Hi End Ultra versus Moondrop Kadenz:

The Moondrop Kadenz takes a refined approach to bass, focusing on precision and control rather than raw intensity. Its subbass extends deeply but with a measured presence, creating a clean foundation that excels in subtle, emotive compositions where low-end clarity is paramount. Its midbass, however, can feel slightly restrained in high-energy genres like hip-hop. The EarAcoustic SPA-Hi End Ultra, in contrast, offers a richer, more dynamic bass response, with fuller midbass that adds warmth and impact to complex, rhythm-driven passages. This makes the SPA-Hi End Ultra particularly immersive for EDM, rock, and pop, though its enthusiastic low-end can occasionally overshadow finer details in classical music. For listeners seeking a visceral bass experience, the SPA-Hi End Ultra subtly takes the lead, while the Kadenz remains compelling for genres like jazz, where controlled bass preserves overall balance.

In the midrange, the Kadenz delivers a vocal-forward presentation, with a hint of warmth in the lower mids that gives male vocals a natural and engaging quality. Its upper midrange is slightly tempered to avoid harshness, yet it captures intricate vocal nuances with impressive clarity, particularly for female vocals. The SPA-Hi End Ultra, while less forward in the mids, provides a smoother and more cohesive transition across the midrange, creating a lush, immersive sound for orchestral and instrumental works. The Kadenz’s clarity gives it an advantage in vocal-centric acoustic genres, but the SPA-Hi End Ultra’s balanced midrange suits a broader range of music, especially rock and electronic, where vocals blend seamlessly with instrumentation. The SPA-Hi End Ultra’s mids, though not as detailed as the Kadenz’s in intimate settings, maintain a consistently pleasing tone across diverse genres.

The Kadenz’s treble is tuned for smoothness, offering a fatigue-free listening experience with well-extended highs that add sparkle to detailed soundscapes. Its controlled treble avoids harshness, making it ideal for genres with aggressive high frequencies, where cymbals and percussion remain clear yet non-fatiguing. The SPA-Hi End Ultra, however, introduces a touch more brilliance to its treble, enhancing airiness and detail in jazz and classical compositions. This added vibrancy gives the SPA-Hi End Ultra a slight edge for listeners who value high-frequency nuance, though its brighter tilt may feel intense over long sessions. The Kadenz’s refined treble ensures versatility across various music styles, but the SPA-Hi End Ultra’s lively highs deliver a more engaging experience for those prioritizing detail.

In terms of soundstage and imaging, the Kadenz produces a slightly more expansive and precise spatial presentation, with greater depth and separation in complex, layered compositions. Its imaging excels in soundscapes requiring pinpoint accuracy, where individual elements are distinctly positioned. The SPA-Hi End Ultra responds with a wide, enveloping soundstage that enhances the energy of live performances and electronic music. While the Kadenz’s imaging is superior for orchestral and acoustic genres, the SPA-Hi End Ultra’s open and dynamic soundstage creates a more immersive experience in high-energy music. The SPA-Hi End Ultra’s ability to maintain a cohesive and engaging spatial presentation across genres gives it a subtle advantage for listeners seeking versatility.

 

Conclusion:

The EarAcoustic Audio SPA-Hi End Ultra is a compelling IEM that marries a luxurious design with a vibrant, dynamic sound signature. Its zinc alloy shell and mirror silver finish, particularly the stunning diamond-patterned faceplate, make it a visual standout, though the finish is prone to fingerprints and scratches. The ergonomic fit ensures comfort for extended listening, and the accessory package, while not exhaustive, is well-executed with a high-quality cable and sturdy carrying case.

Sound-wise, the SPA-Hi End Ultra delivers a bold, V-shaped tuning with punchy bass, articulate mids, and sparkling treble, supported by a spacious soundstage. Its energetic presentation excels in genres like rock, pop, and electronic music, though it may not suit listeners seeking a neutral or mid-forward sound. For example, compared to the Moondrop Kadenz, it offers a more impactful and lively sound at the expense of some precision and balance, catering to those who prioritize excitement over refinement.

 

Pros & Cons:

• + Vibrant, V-shaped sound with punchy bass and detailed treble
• + Premium zinc alloy build with a luxurious mirror silver finish
• + Comfortable ergonomic design for extended use
• + High-quality, tangle-free Litz cable
• + Easy to drive with a variety of sources
• + Spacious soundstage for an immersive experience 

 

• – Mirror silver finish is prone to fingerprints and scratches
• – Fixed 3.5mm cable lacks versatility for balanced setups

 

Thank you for the Read!