TAS Commitment
Description
EarAcoustic SPA-Hi End Series IEM – Redefining High-End Audiophile Listening
Discover the EarAcoustic SPA-Hi End Series, a pinnacle of innovation and acoustic engineering built for audiophiles who demand the very best. This high-end in-ear monitor series includes four premium models—SPA-Hi End, SPA-Hi End Ultra, SPA-Hi End MAX, and the SPA-Limited Edition—each designed to deliver a rich, immersive soundstage, low distortion, and remarkable detail retrieval.
Engineered with low impedance and high sensitivity, these IEMs are easy to drive while offering extraordinary sonic performance. The Ultra and MAX models elevate sound reproduction with higher thrust, while the Limited Edition model delivers intricate detail, exceptional warmth, and elite-grade durability.
Advanced Tesla Technology for True Audio Precision
At the heart of the SPA-Hi End Series lies an advanced dual magnetic Tesla coil design powered by a high-flux N52 magnet exceeding 10,000GS. This setup provides enhanced dynamic range, pinpoint accuracy, and a full-bodied listening experience, outperforming traditional driver configurations.
Revolutionary Diaphragm Design for Sonic Clarity
Featuring a Titanium Gold Ball Top diaphragm and double-sided vapor-deposition silicon crystal hanging edge, these IEMs deliver smooth frequency response with ultra-low distortion. With a Titanium vibration modulus of 105–110 GPa, they respond swiftly to audio signals, ensuring rich layers, precise imaging, and exceptional detail across genres.
Flagship-Level Acoustic Tuning
Crafted through hundreds of acoustic simulations, the SPA-Hi End Series is tuned to a flagship-grade target frequency response, offering a wideband range from 5Hz to 40,000Hz. This translates to expansive sound fields, engaging warmth, and realistic spatial imaging—perfect for critical listening and emotional musical connection.
Uncompromising Technical Specs
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Total Harmonic Distortion (THD): < 0.5% for pure, clean audio
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Intermodulation Distortion: < 0.05% for sonic clarity
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Sensitivity: > 109dB/mW for effortless driving
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Transient Response Time: < 3ms for rapid signal delivery
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Low-Frequency Rebound: ≈ 40ms for rich, textured bass
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Signal Attenuation: < 0.5dB for undistorted high-fidelity sound
Premium Build for Audiophile Comfort
Every model is ergonomically designed and built with precision:
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SPA-Hi End: 3D resin printing with matte silver finish
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SPA-Hi End Ultra: CNC-machined zinc alloy with mirror silver electroplating
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SPA-Hi End MAX: Aerospace aluminum alloy via five-axis CNC and mirror plating
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Shell Design: Uses 7075 ultra-strong alloy, diamond-cut textures, and resin coating
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SR Blue Label: Clearly marks the left ear for ease of use
Audiophile-Grade Coaxial Cable
Bundled with a high-definition coaxial audio cable, made of oxygen-free copper and silver-plated cores, the SPA series ensures minimal signal loss and interference. With a 0.78mm dual-pin design and 408 core strands, this cable offers crystal-clear transmission and unmatched durability.
Whether you're a critical listener, studio professional, or a passionate audiophile, the EarAcoustic SPA-Hi End Series IEM offers the perfect balance of cutting-edge technology, robust craftsmanship, and emotionally rich sound.
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OUR HONEST REVIEWS FROM THE CO-FOUNDERS & AUDIOPHILES
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TRUSTED BY OVER 45K+ MUSIC ENTHUSIASTS
Let customers speak for us
It is the best and clean sounding IEM, perfect for the Beginner.
I love the fact that I can change the nozzle and its a little different sounding, so its two in one.
The cable quality is out of the world no external sound when I touch it.
I can hear so many details clearly. I say please go for this, it is perfect first IEM and the Perfect Upgrade if you had IEM under 2k before
It provides Awesome sound quality go and buy it m
🎧 KZ Castor Pro IEM – Review
🔊 Sound Quality
The KZ Castor Pro delivers clear and detailed sound with excellent separation across lows, mids, and highs. The decent thumping bass is tight and controlled, giving energy to tracks without overwhelming the vocals or instruments. Its super-balanced tuning ensures a natural, enjoyable listening experience suitable for all genres.
🎚 Unique DIP Switch Equalizer
What sets the Castor Pro apart is its DIP switch physical equalizer. With up to 16 different tuning options, it allows listeners to adjust the sound profile on the go—boosting bass, enhancing treble, or keeping it neutral. This feature gives it a level of flexibility rarely seen in IEMs at this price point.
🔇 Noise Isolation
Although it lacks active noise cancellation, the design offers an excellent passive seal. The snug fit ensures that outside noise is effectively blocked, making the listening experience immersive and ensuring ANC doesn’t feel like a missing feature.
🎼 Hi-Res & DAC Performance
For those using Hi-Res lossless audio, pairing the Castor Pro with a DAC is highly recommended. The extra power and clarity from a DAC enhance the already impressive soundstage, detail retrieval, and overall dynamics, making the listening experience truly premium.
💰 Value for Money
At its smart price, the KZ Castor Pro punches well above its weight. It combines detailed sound, punchy bass, balanced tuning, and innovative features—making it a strong choice for both audiophiles on a budget and everyday music lovers.
Have been using these buds for like an year now, they gave me a great time all that while, only recently the cable started getting green and there was an issue with audio drop on even a slight movement (like every earphone ever), but still a great investment for an year.
Got this as my first iem from audio store.. much much more worth than the price.. the bass!!.. my gawddd, it's something which is gonna surprise you.. I got it paired with the moondrop echo a dac.. and trust me, couldn't have asked for anything better.. and the delivery was done to me in kolkata, just within a day.. remarkable job audio store!♥️
Loved the new gear they sound absolutely phenomenal and mind if say the looks and aesthetic of the KZ Castor Pro is underrated for its price, as a newbie I was a little hesitant to jump in this rabbit hole, but it was worth it. Shoutout to The Audio Store to build up my courage, they were very helpful as I was placing my order I fumbled and they responded very positively and helped me correct my mistake. Thank You
Excellent performance with ANC good mic this song is like heaven
It is better compared to normal tws
Perfect for beginners to start their audiofile journey
I'm satisfied and convinced of this product
The packaging
The quality
And The performance
Trust he go for this one if you never try this one
Just give it a try you will not regret it
I have manny IEM's I'm my collection
But this one is really fantastic
Thanks to The Audio Store
They have many discount in compar to others in market
And shippment is on the time no worrys
1999 is nothing the engineering is perfect of this IEM,,,
Amzing product
Love the way it sounds rich in every range perfect for beginners but if you're not a bass head go for non bass varient.
This is my first ever IEM that I purchased after research of couple of months. And I can say that this was a good decision on my end. Cable is good. Buds look stylish. Comes with a small carry pouch and 6 pairs of ear tips. Sound quality is awesome. Love the instrument separation. Customisable EQ gives them versatility. You can actually experience how other IEM sound just be playing around with the EQ.
Actually, l'm new to this IEM world. Such an amazing product. If you are new to iem just as me, I would highly recommend his product to try out. The OG. There are 16 types of tuning options to play around and explore your favourite music in a new way and the build quality is also pretty good. Overall a nice product 👍.
Good sound
5/5 Mids and Highs
5/5 Well balanced Bass, doesn't overpower the music
5/5 Design look premium and classy
They are quiet heavy and huge
