ISN Neo1

ISN Neo1

Introduction

ISN Audio has steadily built a reputation in the audiophile world, originally gaining recognition for high-quality aftermarket cables that enhanced the sound of many well-regarded IEMs and earbuds. Their expertise in materials and sound tuning eventually led them to develop their own line of IEMs and earbuds, blending premium craftsmanship with carefully refined tuning. Over the years, ISN has proven that you don’t need to spend a fortune to experience great sound, and the Neo1 is yet another testament to this philosophy.

Now in its second batch, the Neo1 stands out with its elegant wooden faceplate and, more importantly, its Carbon Nanotube (CNT) dynamic driver—a technology once reserved for high-end models, now available at an affordable price. CNT diaphragms are ultra-thin yet rigid, allowing them to deliver faster transients, excellent clarity, and a natural timbre. Many budget IEMs struggle with refinement, often leaning too warm and muddy or too bright and fatiguing, but ISN has managed to strike a perfect balance with the Neo1’s organic and engaging sound signature.

One of the standout features is the interchangeable filter system, allowing users to fine-tune the sound to their preference. Whether you enjoy a neutral, airy presentation or prefer a warmer, fuller-bodied sound, the Neo1 offers flexibility that’s rare at this price point. This, combined with its strong technical performance, makes it a serious competitor in the sub-$100 IEM market.

After spending extensive time with the Neo1 across various sources, I can confidently say it competes with IEMs that cost significantly more, Its rich, textured mids, controlled bass, and smooth yet extended treble make it an excellent choice for audiophiles on a budget. In a market filled with overly hyped budget IEMs, the Neo1 stands out as a true gem—not just because of its affordability, but because it actually delivers high-quality sound that feels premium.

Specification

Brand:ISN Audio

Model: Neo 1

Driver: 10mm full frequency carbon nanotube diaphragm

Sensitivity: 105dB

Impedance: 22ohm

Passive noise reduction: 26dB

Frequency response: 10 ~ 20kHz

Cable: 4 strands OFC silver-plated wire

Connector: 2pin 0.78mm

Plug: 3.5mm Audio

Cable length: 1.2M

Package

ISN Neo 1 IEM

3 pairs of orange silicone eartips (SML)

3 pairs of green silicone eartips (SML)

Carry case

Clip

Link where you can buy it: https://penonaudio.com/ISN-Audio-NEO-1.html




Design and Build Quality

One of the first things that stood out to me is the Neo1’s beautiful wooden faceplate. Unlike the usual flashy designs seen in budget IEMs, this wooden aesthetic gives it a premium and classy touch. The plastic housing keeps it lightweight and comfortable for long listening sessions, ensuring no fatigue even after hours of use.

The included 2-pin cable is of decent quality, free from microphonics, and provides a secure connection. Passive isolation is also quite good, effectively blocking moderate external noise, making the Neo1 a great option for daily commutes



Interchangeable Filter System

The real highlight here is the interchangeable filter system, which subtly adjusts the sound signature:

• Metal Mesh (Red on the graph): Adds more energy and enhances the dynamics.
• Damping Mesh (Blue on the graph): Balances the sound, tightening the bass and improving midrange clarity.
• Cotton Mesh (Green on the graph): Softens treble peaks, creating a more organic and relaxed sound.

NOTE: For those who prefer an even warmer and smoother sound, there’s a special tweak—stacking the Metal Mesh filter on top of the Cotton Mesh filter. This enhances the warmth and refinement of the Neo1, delivering an even more organic and laid-back listening experience.

Who Should Buy the ISN Neo1?

✔ Audio enthusiasts who want an affordable IEM featuring a Carbon Nanotube (CNT) driver, delivering fast, detailed, and natural sound.
✔ Listeners who appreciate tuning flexibility, thanks to the interchangeable filter system, allowing them to tweak the sound to their preference.
✔ Fans of a balanced, warm, and organic sound signature, without excessive brightness or harsh treble.
✔ Users who want a stylish yet affordable IEM, featuring a beautiful wooden faceplate and premium build quality.
✔ Those who prioritize comfort for long listening sessions, as the lightweight housing ensures a fatigue-free experience.

Sound Performance

Overall Sound Signature

The Neo1 delivers a balanced and natural tuning with a touch of warmth, making it an easy and enjoyable listen. The CNT driver plays a big role in its organic and musical presentation, giving the sound a natural flow without sounding overly analytical or artificial.

Soundstage & Imaging

For an IEM in this price range, the Neo1 delivers an impressively wide and spacious soundstage. It doesn't feel artificially expanded, but rather naturally open, giving instruments room to breathe. There’s a good sense of depth and layering, making the overall presentation feel more immersive and three-dimensional.

Imaging is another strong point—the placement of instruments and vocals is well-defined, making it easy to pinpoint where sounds are coming from. Whether it’s guitars panned to the sides, drums sitting deep in the mix, or a lead vocal right in the center, everything is placed with precision. Even in fast, complex tracks, the Neo1 maintains clarity and separation, preventing instruments from blending together.

Bass

The CNT driver delivers tight, well-textured bass with excellent control. The sub-bass extends deep without becoming overwhelming, while the mid-bass remains punchy yet clean, ensuring that low frequencies stay well-defined and impactful without bleeding into the mids. Unlike some budget IEMs that struggle with boomy or bloated bass, the Neo1 keeps the low end vivid and energetic while maintaining balance across the frequency range.

Tuning Filters and Their Effect on Bass

Metal Mesh – Enhances bass impact, adding a more dynamic and engaging low end. Perfect for those who enjoy a fun, lively presentation with a stronger sense of rhythm.

Damping Mesh – Tightens the bass, making it more precise and controlled. This filter is ideal for listeners who prefer a clean, audiophile-friendly tuning, where every note is well-defined and articulate.

Cotton Mesh – Warms up the bass, giving it a more natural and organic feel. The texture remains detailed, but the overall presentation is softer and more relaxed, perfect for those who enjoy a smooth and cozy listening experience.

Metal Mesh Tweak – Further enhances warmth and smoothness while preserving clarity and control. This setting gives a slightly richer bass presence without overpowering the rest of the sound, making it great for those who want added fullness without sacrificing detail.

Test Track: Billie Eilish - Bad Guy

The deep bass notes in this track hit with clarity and precision, never overpowering the mix. The sub-bass rumbles naturally, adding depth without turning into a boomy, overpowering wall of sound. The mid-bass punch keeps the rhythm energetic, while the CNT driver’s speed ensures each bass hit remains distinct and well-separated from the vocals and treble. Whether using the Metal Mesh for extra impact or the Damping Mesh for a more refined approach, the Neo1’s bass remains controlled, engaging, and non-fatiguing—perfect for both casual and critical listening.

Midrange Performance

Some people say the Neo1 has a V-shaped tuning, but for me, it doesn’t really fit that description. The mids aren’t recessed, nor are they overly forward. If anything, I’d call it balanced or even W-shaped, since the midrange has just the right presence—not pushed back, not in your face, just perfectly placed in the mix. It also doesn’t have thin mids; instead, the CNT driver adds a natural thickness and weight, making vocals and instruments sound full, organic, and engaging.

Both male and female vocals come through clear, textured, and natural, while acoustic instruments retain excellent timbre and detail. Whether it’s soft piano notes or an emotional vocal performance, the Neo1 keeps everything rich and lifelike without overdoing it.

By default, the Neo1 comes with the Cotton Mesh filter as its stock tuning, which already delivers a natural and organic midrange presentation. But if you want to tweak the sound further, the other tuning filters offer additional options.

Tuning Filters and How They Affect the Midrange

Metal Mesh – Leans slightly toward a V-shape, pulling the mids back a little while boosting the bass and treble. This setting works well for those who enjoy an energetic and contrasty sound.

Damping Mesh – Brings vocals slightly forward, adding clarity and presence without making them sound unnatural. If you like a bit more presence in the mids, this is a great option.

Cotton Mesh (Stock Tuning) – Delivers the most natural and organic midrange, making vocals and instruments warm, full-bodied, and immersive. This is perfect for acoustic and vocal-centric genres.

Metal Mesh Tweak – Smooths out the mids, refining the vocal warmth and keeping everything cohesive and well-blended. A great choice for those who prefer a relaxed but still detailed midrange.

Test Track: Adele - Hello

Adele’s voice is rich, powerful, and deeply expressive, and the Neo1 captures all the subtle details in her delivery. The breathy whispers in the verses and the strong, emotional push in the chorus all come through with clarity and depth.

Treble Performance

I’d describe the highs on the Neo1 as crisp, airy, and well-extended but never harsh. It has just the right amount of treble energy to keep things detailed and engaging without introducing any unwanted sharpness. There’s no sibilance, no artificial brightness—just smooth, refined highs that add clarity without fatigue.

Some might expect a CNT driver to be overly aggressive in the treble, but that’s not the case here. The Neo1 manages to balance sparkle and smoothness, making cymbals, electric guitars, and high-pitched vocals sound clear and natural. It has enough air and openness to prevent the sound from feeling congested, but it doesn’t push the highs too far to the point of being fatiguing.

Tuning Filters and How They Affect the Treble

Metal Mesh – Adds a bit more sparkle and energy, giving the highs extra crispness and definition. Great for those who want a more exciting, detailed treble.

Damping Mesh – Smooths out the highs while keeping them clear and non-fatiguing. This is a nice balance if you want clarity without added sharpness.

Cotton Mesh (Stock Tuning) – Delivers the most natural and balanced treble, keeping things airy and relaxed without losing detail. Ideal for long listening sessions.

Metal Mesh Tweak – Softens any harsh edges while keeping treble extension intact. A great option for a laid-back but still detailed presentation.

Test Track: Foo Fighters – Everlong

The crashing cymbals, layered electric guitars, and Dave Grohl’s raw vocals all come through with clarity and energy without sounding harsh. The Neo1 handles the fast-paced strumming and drum attacks with great separation, keeping everything coherent and detailed even when the mix gets intense.

With Cotton Mesh (stock tuning), the treble stays smooth and fatigue-free, letting the guitars sound full-bodied and natural. Switching to Metal Mesh adds a bit more bite and attack, making the song feel even more energetic. No matter the setting, the Neo1 ensures the highs remain clear, well-controlled, and never piercing, making it a great choice for rock and alternative tracks.



Source Pairing & Synergy

The Neo1 pairs well with different sources, and the synergy can really change how it presents its sound. I tested it with a few DACs and dongles, and here’s how they affect its performance:

iBasso DC Elite – This pairing gives the Neo1 a highly musical presentation with a full-bodied bass, clean mids, and airy treble. The Elite’s natural tuning complements the Neo1’s balance, making it a great all-rounder for casual and critical listening.



Hiby FC6 – This brings an R2R-like smoothness, making the mids sound sweeter and more intimate. It’s a great match if you prefer a slightly warmer, more relaxed presentation without sacrificing detail. Vocals feel more emotional and textured, adding an almost analog-like character.



Earmen Colibri – With this, the Neo1 remains natural and neutral, letting its inherent tuning shine. The Colibri doesn’t overly color the sound, instead preserving the IEM’s clarity and detail. If you want to experience the Neo1 in its most accurate and uncolored form, this is a solid pairing.



Hidizs S9 Pro Martha – Enhances the midrange presence, bringing more life and emotion to vocals while maintaining a smooth and controlled treble. If you want the Neo1’s mids to stand out more, this pairing helps push them forward slightly without making them shouty.



Best Use Cases

Gaming & Movies – The wide soundstage and precise imaging make the Neo1 a solid choice for FPS games and cinematic experiences. Positional cues in competitive gaming are easy to pinpoint, while action sequences in movies feel more immersive.

Portable vs. Desktop Setup – The Neo1 runs well on dongles like the VE ODO, which gives it enough power while maintaining a clean and organic sound. However, it scales better with powerful DACs like the Topping E70 Velvet, where the bass becomes even tighter, and the treble extends further, making everything sound more refined.

🛠 Eartip Rolling – Swapping tips can bring out different aspects of the Neo1’s sound:

• Final E tips – Enhance bass impact and sub-bass depth, making it more engaging for those who like a fuller low end.
• SpinFit CP100 – Improves comfort and treble clarity, making the sound a bit more open and detailed without making it harsh.
• Foam Tips – Provide a warmer and smoother sound by slightly reducing treble energy while improving isolation. This results in a more intimate and relaxed presentation, making vocals sound richer and bass slightly more pronounced.

Overall, the Neo1 is versatile and adapts well to different setups. Whether you want a musical and warm experience, a neutral and transparent sound, or a more intimate and emotional tuning, the right source can fine-tune the listening experience to your preference.

Comparison

ISN Neo1 vs. Truthear Hexa

The Hexa leans towards a neutral and analytical tuning, with less warmth and musicality than the Neo1. While the Hexa provides excellent clarity and separation, it lacks the engaging, organic tonality that makes the Neo1 stand out. For those seeking a more natural and immersive sound, the Neo1 is the better choice.

ISn Neo1 vs Tin Hifi T2

The Tin HiFi T2 is renowned for its neutral and bright tuning, offering a detail-oriented sound with an emphasis on clarity. However, this tuning can sometimes result in a thinner bass response and a brighter treble, which may be perceived as harsh by some listeners.

In contrast, the ISN Neo1 provides a fuller, more natural sound signature. Its bass is tight and well-textured, delivering depth without overshadowing the midrange. The midrange itself is clear and organic, ensuring vocals and instruments are both engaging and lifelike. Additionally, the Neo1's treble is airy and refined, offering clarity without introducing harshness.


Final Thoughts

The ISN Neo1 stands out as a remarkable contender in the budget IEM market, offering a combination of refined tuning, premium aesthetics, and an innovative interchangeable filter system. Its ability to adapt to different sound preferences makes it a versatile choice for both casual listeners and audiophiles seeking a high-value, budget-friendly IEM.

With its well-implemented Carbon Nanotube (CNT) dynamic driver, the Neo1 delivers a natural, engaging, and immersive listening experience. The soundstage is spacious, imaging is precise, and the tonal balance remains musical and organic across different filter configurations. Whether you prefer a more energetic, balanced, or smoother sound, the Neo1 effortlessly adjusts to your preferences, making it a compelling option in its price class.

Considering its performance, versatility, and craftsmanship, the ISN Neo1 exceeds expectations and competes with IEMs well beyond its price bracket. For those in search of a budget-friendly yet highly capable in-ear monitor, the Neo1 is an outstanding choice that delivers both technical prowess and musical enjoyment.

How much do you need to pay for good sound?

Depending on who you ask answers will vary, and the pace of technological improvement is making us revise our answers every year.

Five years ago a few hundred spent on earphones didn't go far, and five years before that spending several hundred could land you IEMs that were objectively terrible.

Fast forward to the present - ISN offered to send me a pair of their new USD $39 ISN Neo1 IEMs in exchange for a review, and if you read me gushing over their Neo5s (my favourite 2023 IEM under $500) you won't be surprised I jumped at the chance.

I've become a bit of a basshead lately -partly thanks to the Neo5s- and bass is ISN's forte. So I expected they'd be bassy, and reading they sport a 10mm carbon nanotube DD suggested they could perform beyond the norm for IEMs in this bracket.

So how much performance can we expect under $50 from a single driver?

Packaging​

The ISN Neo1s arrive in a very small cardboard box, inside is a fabric carry case which is well-shaped to occupy a pants pocket.

Inside are the earphones & stock cable, two sets of silicone eartips in three sizes, a shirt clip and three sets of acoustic filters I'll discuss later.

The stock OFC silver-plated 2pin cable is unfortunately only available in a 3.5mm termination, and is as flimsy as you'd expect for an IEM in this price range - I'd be inclined to spend a few dollars replacing it with a higher quality quality 4.4mm cable. The entire package is fairly minimal, but for $39 it's impressive they've included as many accessories as they have.

Ergonomics​

The Neo1s are ergonomically superb. For starters they weigh next to nothing, even compared to many budget hybrid IEMs they're unbelievably light and the shells feel smooth against the skin. They're also highly sculpted to match one's ear geometry and feel right at home in mine.

Furthermore despite their weight they isolate far more impressively than expected from ultralight IEMs thanks to how effectively their shape blocks the ear canal, making them ideal for public transport use.

The stock cable isn't going to win any awards for aesthetics or performance, but feels sturdy at the connectors where cables most commonly break. It'll get the job done I suppose, but can easily be improved upon if you're willing to spend a bit extra.

Sound Impressions​

I tested the Neo1s with my Hiby R6 Pro II set to hi-gain in AB mode with a volume level of 17.

They immediately come across as slightly v-shaped with deep, boosted sub bass and very prominent treble, yet the more I listen the more I notice the forward presence of their midrange.

Sub bass is boosted slightly north of neutral & certainly won't feel deficient with bass-driven electronic music, but midbass is more restrained. That prevents the midrange being overwhelmed, but also means the Neo1s don't throb enough down low to be considered basshead IEMs - they're too well balanced.

Shifting to the midrange, vocals are positioned quite forward in the soundstage and have a decent amount of weight behind them. There's a fairly even-handed balance between the lower and upper midrange, so I'd struggle to label the Neo1s as tonally warm or cool... but rather quite neutral.

If anything I'd prefer a little more lower midrange boost, but given we have a single driver covering the entire frequency range that might result in a sacrifice being made elsewhere - for $39 they do a terrific job of covering the entire spectrum without any obvious gaping holes.





Treble is fairly bright on the Neo1s, which has perhaps been boosted to increase the perception of detail. Treble's well within my levels of tolerance, but as this is a very personal thing ISN have included a number acoustic filters to dampen treble should you require it.

Regrettably treble quality is an issue - it tends to be rather wispy & indistinct, lacking the smooth effortlessness & body often heard in IEMs with vastly higher prices. For $39 however the Neo1s don't feel dark, nor do I find treble screechy or piercing. I would nominate treble as their weakest area however.

The Neo1s feature a 4.5khz peak which some listeners will like less than others. If you want it dampened, three sets of acoustic filters (4 each) are included - stock metal grilles which block it least, dampening mesh filters that lower it slightly & cotton mesh filters which tame it more. The peak doesn't bother me even with the stock filters, but those options are handy and you can even stack filters.

Technical Performance​

As a budget single-driver IEM, expectations for Neo1 technical performance must be kept reasonable to avoid disappointment. Within that context they perform quite well, though budget multi-driver hybrids can reach greater technical heights at the cost of coherency & tonality.

The Neo1s are extremely coherent as you'd expect from a single-DD, but the positives don't end there. Their soundstage is impressively wide by budget standards, successfully avoiding feeling claustrophobic despite the stage being quite shallow - which is fairly typical for low cost IEMs. My ears aren't tricked into believing multiple-BAs are creating the stage I'm hearing, but nor is it distractingly tiny either.

Resolution is a similar story - it won't blow away anyone who's sampled expensive IEMs, but considering the Neo1s' cost & single driver feels acceptable. You'll miss out on hearing notes trailing off into nothingness with pristine clarity, nor are instruments separated with ample blackness around them. However I don't get the impression notes are being smeared together in a single blob as was often the case with budget DDs of the past - how far driver tech has come!

Which brings me to the question of speed. No, these aren't the absolute fastest DD's I've heard, but they're perfectly decent at keeping up with fast-paced electronic & classical music I can't get enough of. Multi-BA IEMs will perform even better in that regard, but the difference feels modest.

One thing I don't particularly like is that as with a lot of budget earphones, individual instruments & voices can sound quite small on the Neo1s, which is mostly noticeable after swapping to more expensive IEMs.

IEM Comparisons​

I compared the Neo1s to similarly-priced IEMs on the Hiby R6 Pro II set to hi-gain in AB mode, with the Neo1s requiring a volume of 17.



NiceHCK DB2 – 1xDD (USD $22)



Extremely light & highly sculpted to ear geometry, DB2 comfort is decent but not quite as amazing as I would’ve guessed as they feel than bigger than they look when worn. Needing only 17 volume on the R6P2 they’re extremely easy to drive.

I like to present the pros & cons of each IEM when comparing them, but am struggling to think of areas where the DB2s eclipse the Neo1s. The DB2 soundstage is narrower & shallower, resolution is lower, they do have a little bit more midbass though less sub bass & lower bass quantity overall.

The DB2 background isn't as black, they may be a tad more coherent but that could just be a perception resulting from smaller stage dimensions, and overall they sound flatter with poorer dynamics & less note weight, and individual instruments sound smaller.



Truthear Zero – 2xDD (USD $49)



Despite being very bulky the Zeros are extremely light, and fit better than you’d think by looking at them. Isolation is merely average as they don’t seal off the ear canal as well as some of the more sculpted IEMs. Requiring 25 volume on the R6P2 they’re a bit harder to drive.

The Zeros' present a thinner tonality, with more upper midrange emphasis that can lead to vocals sounding a bit clearer but at the cost of a more natural tonality. Their soundstage is wider but also flatter, I find their bass texture is very disappointing and sub bass in particular just isn't there.

Compared to the Neo1s they're more relaxed with a more neutral & less v-shaped tuning some may prefer. However not only is their DD slower, but their background isn't as black, and they don't sound as refined especially in the treble where things can be quite grainy, and dynamics are lower.



NiceHCK F1 Pro – 1xPlanar (USD $99)



The F1 Pros’ small metal shells feel like they weigh next to nothing, and are extremely comfortable. Isolation however suffers because there isn’t a lot of mass blocking the ear canal. Requiring 24 volume on the R6P2 they need a bit more power to drive.

The planar drivers of the F1 Pro are much more technically capable than the Neo1's DDs and as such deliver far higher resolution across most frequencies, with a wider & deeper soundstage, a blacker background, and can keep up with complex passages of music even better.

However the F1 Pros are much brighter & more neutral whereas the Neo1s are more bass-driven with more midbass in particular, and I find Neo1 vocals have a little bit more weight behind them due to more lower midrange presence, the Neo1s are also quite a lot darker.



Simgot EM6L – 4xBA 1xDD (USD $109)



The EM6L shells are very heavy and I do notice their weight even during short listening sessions, however their shape is fairly comfortable and isolation is quite good thanks to all that mass. Needing 23 vol on the R6P2 they’re a bit harder to drive.

The EM6Ls deliver a much thinner, Harman-tuned sound with much more upper midrange focus that I don't particularly care for. However on the technical front their hyrid configuration let's them deliver a wider & deeper soundstage, slightly higher resolution, and a blacker background.

The Neo1s by contrast sound much less refined & feel more congested, though their tonality is more believable and they're slightly more coherent, with a more fun bass-driven sound that isn't as polite.

Cable Comparisons​

I tested the Neo1s with a number of budget cables to gauge how effectively they respond to cable rolling.



NiceHCK Blacksoul (USD $50)



In this fairly impressive pairing BlackSoul makes the Neo1s sound flatter and smoother, with a slightly wider soundstage that's also a touch deeper.

I also hear a slightly more detailed midrange which I didn't expect, note weight is a bit more prevalent and even bass has slightly more impact. Treble feels a tad muted which is typical for BlackSoul, but doesn't negatively impact the pairing for my taste.



ISN S4 (USD $55)



The S4 has always been great for boosting sub bass, and I do hear a slight uptick in that department with the Neo1s. The soundstage is also a little wider, and overall the presentation is brighter which helps make imaging feel a touch clearer.

However overall I don't feel the improvements to technicalities are worth the S4 imparting a thinner & cooler tonality that I don't really care for.



Penon Vocal (USD $69)



Vocal performs in accordance with its' name by bringing the midrange forward, adding more gravitas & note weight to vocals and increasing their resolution.

Dynamics are also slightly improved, the background is a little blacker and there's a slight uptick in midbass in this decent cable pairing.



Simgot LC7 (USD $69)



LC7 improves Neo1 dynamics substantially, widens the stage, improves note weight, delivers a blacker background & increases midrange resolution.

This cable does impart a metallic tonality I don't particularly like, but the technical improvements feel dramatic enough to be worth it.

Conclusion​

The ISN Neo1s are a prime example of how little you need to spend on a decent pair of IEMs these days.

They're insanely light, comfortable, isolation is terrific, they look great & sound good by budget standards.

For USD $39 they're the perfect backup pair of IEMs in case your more expensive set breaks, or just to throw in a gym bag without worrying if they get scratched.

Sonically bass is the highlight, vocals are quite impressive, they don't sound claustrophobic and the drivers are fast enough to keep up. Treble's a bit grainy, technical chops like resolution & imaging aren't amazing but for $39 I have no complaints.

I'm a bit surprised bass isn't even more dominant (they're an ISN IEM after all!) but assume that was decided to keep them more neutral, so they work better as all-rounders. Treble prominence could be an issue if you're sensitive, but they include swappable filters to tone it down.

I still recommend stretching your budget to the Neo5s if you can afford them, but it's pretty amazing how much of their performance you get from the Neo1s for 13% of the cost.

The ISN Neo1
Redcarmoose Labs November 27, 2023

Introduction and build:
The Neo1 comes in at an easy to wear 4 grams a piece. A 10mm CNT driver does the sound, and there is one single air-vent in the middle of the back of the housing. Due to the exquisite form/shape and weight the Neo1 may actually be the most comfortable IEM I have come across all year. Such charms can double in value once you leave the house. Seemingly not that thick, yet sporting a wide treated wood faceplate, we are gifted with aesthetics of a much pricer IEM. As seen in the pictures here, the nozzle is also the perfect length allowing me to go ahead with my preferred wide-bore silicone ear-tips. With dealing with a single 10mm CNT driver and Penon it seems have actually built a housing around the driver, maximizing ergonomics found when you don’t have to build a giant IEM shape to accommodate the innards. The shape arrives simple, as a single driver laid facing upwards into the nozzle, invents such a wide, yet thin shape. With the back body I can see formation of construction lines traveling the whole length, even up to the nozzle. Such lines are very different from the standard 3D printed resin formations regularly found here at Redcarmoose Labs. Yet maybe it’s the material, or maybe the shape or maybe both, but it is truly a joy to wear, as long as I want, never even moving or acting fussy.

The filter kit:
The birth of the Neo1 happened it two stages. It was released, yet some wanted a slight reduction of the 4.5kHz peak. So as a permanent fix you have both a Dampening mesh or Cotton mesh to add, if you prefer. I will be moving forward in this review with the Cotton mesh in place. Yet, remember if your game for exactly how it sounds out of the box, go for it!

$39.90
https://penonaudio.com/ISN-Audio-NEO-1

Sound journey:
Often I will start off my tests with a song that is simply easy to get (play-back) right. I mean why cause trouble at the start, we want impressions to be gifted, yet accurate.



Dead Can Dance
Anastasis
Kiko
44.1kHz - 24 bit (ISN Neo1 in place)
Look, while easy to play back, this number also has what we are looking to test as far as dramatic dynamics in sound. Meaning a while later the vocals will show-up and the question is, are they too forward, or too intense, or both? Yet at the start we are gifted with a big round and fully accurate drum rhythm. This is where the money is as far as this IEM goes. Vibrant, big, accurate and holding the most correct timbre. Why? Because it’s a 10mm CNT driver silly. Yep, it is all here the way this 10mm is reproducing accurately the overall sound, feel and vibe of this drum. I know I said the word big, but I’m going to say it again……also the decay is exactly correct. At times IEMs this price range will seem short-handed, especially with note-weight or stage. I can say, that if you took the Neo1 to an IEM show and placed it in someone's ears, no way, no way would they guess (this is) an under $40.00 IEM, this would not happen.

Back to the song:
There is also a cymbal of sorts right at the start and while I have heard it played back slightly more separated into the stage, away from the drum-sound. Still this is nothing to get your panties in a bind about. Truly if I had never heard the song before, it would sound exactly correct, especially how the pace is done……pace, note-weight and timbre…….is there anything else? Oh…..and the staging is nice, where everything has that 10mm cohesiveness and while not the biggest stage it is in-between large and middle size………..which is provocative and truly nice to have here, especially at this price-point. At exactly 00:18 a dramatic introduction of drum emphasis and added instrumentation lets us know we are now getting somewhere as far as moving forward. And here is an example of layering, that in-fact the separation and delineation at hand is what is truly endearing. Often I get called-out as a shill or a talker of un-truths. The point here is I truly like IEMs, and I get them for free, to borrow. I’m simply relaying the character as I hear it, there may be a slight exaggeration at times, but that’s the force of both being an enthusiast and a writer. This is truly how I encounter the ISN Neo1.

At 00:39 a guitar-like (world string) instrument takes place, the thing is, it is in no way too forward or wrong sounding at all. Such a sound grabs onto other effect channels and is brought back into the track reformed into a slightly different tone, also holding different positioning into the stage. Upon further study this is really a form of decay or echo, such an instrument then gets combined with a synth accompaniment, taking our little tune to the next level. At 01:14 Lisa Gerrard’s vocals make an entrance. The ultimate question here is where are they, both in tone and contrasts? This is the tale of quality because the human hearing is specifically tuned to hear the female voice the strongest. This may be designed by our creator or evolutionary………yet the Pinna Gain area either makes or breaks an IEM. This occurs due to micro-sensitivity into perception of this area of hearing. Literally 1/2 or 1/4 kHz will be commonly noted by everyone listening regardless of experience. They may not be able to describe what the effect is exactly, but they will perceive the mood. You see part of this formula is balance, meaning get us a deeper and more robust bass and the Pinna Gain area gets played down. Same almost gets us some treble splashes and also it will ask you to lower your listening volume to in fact reduce again the perception of Pinna Gain. What we are looking for is balance, balance and technicalities. Because at times a boost (unneeded) into the treble can get us the feeling of more detail, when it is just pushing-up the detail that is there. Same as the bass, where there can be a formed and adequate bass, yet set back into the mix. Here is in fact Penon/ISN’s house sound for the bass. Such a display of low end is why people purchase a Penon/ISN. The best way to describe it is full, warm and textured, but not overbearing. ISN is Penon’s company that aligns itself to more bass heavy replay than Penon branded products. And it’s true this has ISN bass DNA written inside of the bass replay.

With that said, the small peak at 4.5kHz takes precedence over all up top, perfectly balancing the bass with maybe a dB or two more energy up-top. This results in the V shape character we experience. Also typically single full-range DDs will always exhibit this style of treble. What this does is offer a very cohesive, non-treble boosted romantic, warm and vibrant tale for your music. Where the thing to look-out for here is still the 4.5kHz peak exploiting dominance over all other aspects of the Neo1 character. This becomes in the end a double-edged sword. One adding the clarity into which we find the vocals moved from the back seat, in some other replays, to front and center. This in and of itself works to create a big stage and takes notice slightly way from the ISN bass. But ultimately it makes these very much vocal IEMs, with a bass boost.

Lisa Gerrard’s voice is something I can touch, and will end-up a spectacle of fascination for those who have never come across such a juxtaposition. At the same time it limits the well-roundedness as experienced with other IEMs, though there is nothing except maybe the SIMGOT EW200 that offers this level of entertainment, at the price of lunch out for two. Except the EW200 has a different tune, to make having both truly complementary.


EW200:
Here is the same song played with the EW200. Such impressions taken from my EW200 review:



Dead Can Dance
Anastasis
Kiko
44.1 kHz - 24 bit (SIMGOT EW200 in place)
While the cymbal ride at the start is not as vivid as I’ve heard with more expensive sets, there is nothing really to complain about. At 00:38 this stringed instrument hits. Seeing Brendan Perry play this live he uses a 8 string Greek Pegasus Trichordo Bouzouki. And while I’ve heard this song for years it is probably the first time in the (this) review that a slight subdued realism is noted. Meaning the treble in the first song and the lows in the last song were fully there and for the most part realistic. And I don’t know why this is but I have often heard it more forward and jumping-out in the mix? Still it’s incredibly natural and while slightly subdued, not in any way a party pooper. In fact once the synth accompaniment takes place it goes to add vibrance and fullness to the song. Though the main concern will be vocals and how they are addressed. At 01:13 Lisa Gerrard makes her entrance, and what an entrance it is! Now all is well, and it wasn’t that the string instrument was bad in any way, it was just slightly farther back and didn’t show the separation that I’m used to, and remember I’m used to hearing this on a more expensive set. It is kind of like different sequences of information take your focus, first the intro of world guitar, then Lisa Gerrard takes the spotlight, only to take it all that much further with her ideas of music on the seductive yangqin (a Chinese hammered dulcimer). At 01:48 we are really at the center of the musical message with both the Yanggin and Greek Pegasus Trichordo Bouzouki playing side by side. The special part is we can differentiate between the instruments. The major part of this success is the note weight, that and the fact that over-all the character of the music is complete, even and correct. At 04:30 there is a wonderful pace to the song that almost becomes a feeling of floating, that’s when Lisa Gerrard comes back again for more vocal tremolos to take this number over the top…….as who needs lyrics?



ISN Neo1 v the SIMGOT EW200:
Let’s cut to the chase here. The EW200 is a full 9 grams, 1 gram more than double the Neo1’s 4 gram weight! And yes, you do notice this stuff, I mean how could you not? In comparison the EW200 has a fuller lower midrange, combined with a less forward pinna and we are basking in a style of murky waters. Don’t get me wrong here, I love the EW200 and have been recommending it to everyone and their Mom…….their Dad and little brother too……even their Sister. The whole Family.

More Nimble:
But here is a chance to find a lighter and more nimble replay, where the bass is actually better defined with the Neo1, and especially when you take away the lower midrange blanket. Now this is where it gets slightly complicated, even though the EW200 is probably more well rounded, it is because of what it's leaving out. Yep, where the Neo1 is fresher sounding and faster, yet at times there is that Pinna Gain which can make some music slightly problematic. Where the EW200 is simply extra lush and more forgiving all the time. But what gets me maybe the most is how the Neo1 stage seems bigger, not so cluttered and cleaner, cleaner to let the pinna gain imaging have more contrast……as it is simply more forward, away from the rest of the mix. Here was the surprising part, before the side-by-sides I would have guessed the EW200 to be the winner across the board. I have more experience with the EW200 and it holds a position of respect here at Redcarmoose Labs. Yet back-to-back the Neo1 showed its character. And when you hear the Neo1 by itself you don’t notice the bass as being careful as it is when you compare it to how the EW200 does bass? You don’t notice how the soundstage is expanded compared to the EW200 when listening to the Neo1 alone?

End of comparisons and end of DCD album Anastasis song review:



Kaveh Cohen, Michael Nielsen
Forza Motorsport OST
Brotherhood
44.1 kHz - 24 bit
While probably the best feature here is how a lower frequency drum can get replayed. Normally this isn’t something I regularly notice because when it comes in at 00:09 it kind-of can get ignored. Meaning this drum is literally the metronome for the whole song holding pace information. Yet once you are clued into the pace of the song, the drum takes on more of a utilitarian role, providing pace substantiation behind the scenes. Of course it’s not behind the scenes, it is just because it never changes your mind looks for other changes and finds them to be intriguing. So this drum just is. Only when you start to compare IEMs there turns-out to be very different ways this metronome drum can be heard. This is a style of orchestra music with electronic music that serves to be a backdrop for game play. So you can imagine how this drum offers a pace and adds drama even while being downplayed by any changes. Except there is one dramatic thing here…………often BAs don’t get this timbre right. Nope, they will go ahead and replay this drum as more of a slap sound. As IEM listeners we have made small compromises. Compromises where we were not too critical of timbre at times. Now the best part is really it is not so bad of a slapping sound with Hybrids, no where it is bad is with all BA IEMs. Yet now with the Neo1 the sound is like a drum, where it’s round and full, containing not a bit of slap…….and I like that. Zero smacking noise! The reason we go with single full-range DDs in the first place.

Bass:
The next part of this song that is money is the bass. Because the standout feature is the fact that the bass holds actual note frequency, and that note frequency is clued in on, and subsequently displayed correctly. The bass is the whole foundation of this song, and I don’t need to give time clues as it is everywhere. Besides note information, we are also given texture. And while it’s not totally the best ever, it is better than the EW200 so that maybe makes it the best bass quality I have heard in the under $40.00 range? Sure it is an ISN product so what do you expect? The bass is simply more clear than the EW200 and with that clearness comes detail…….etc…..etc.

Midrange:
Here we are kind of following the mix as it unfolds. This is an instrumental. As no vocals. Yet the piano keys take that job and run with it. Nice offerings of echoes and such commingling with the bass to create a dance of sorts.

Treble:
And while much of the time (with more expensive IEMs) I will note better separation and itemization inside of what the treble is doing. Here the message is the forwardness to fight the bass in the 4.5kHz region. That is how they can get away with the IEM sounding correct and balanced with-out adding excessive treble energy to the replay. Still due to just how it is tuned we find all is here that is needed or could be asked for. Yes, the treble is downplayed yet, if you had never heard better you would not know. As Penon/ISN are masters at finding a tune, and they found it with the Neo1. The best part of the Neo1 in that regard is the fact that every tone has an area and there is nothing left out to cause concern.

Song summary:
Probably the organic fluidness is what is the most charming here, the fact that all is one, yet each element has its place. The way the bass finds a natural yet smooth and robust way to come into the farther reaches of the stage, the way there can be times when that same exact bass jumps down a few octaves into the sub-bass zone and is relayed with a special style of magic that will have you content no matter how many $$$ big-gun IEMs you have laying around.



Dead Can Dance
Within The Realm Of A Dying Sun
Summoning Of The Muse
88.2 kHz - 24 bit
Ok, now comes the fireworks……………maybe? I mean this is a random test to see where this goes. This album is very well recorded and has great female vocals on the second part of the album. Here we want to discover if things are too much, too little, or just right. Just like the story of Goldilocks………..

At 00:00 it is the ultimate introduction, with fanfare abound……the very first instrument is a bell sound, in fact there is a whole symphony of bell sounds. Slowly at 00:15 our mind is able to slowly find home and in doing so is taking this whole thing apart. Yet surprisingly nothing is too bright, as surely these bells take that sonic positioning, of course, it is the treble doing its thing………only. And again while I have heard this showcased with more detail, treble energy and spatial clues, opening-up a kind of vista to view, here maybe it’s just the price-point? We are fine. Holding regular if not slightly compromised positioning of elements, this is the style of what DDs do in this situation. At 00:26 the vocals join us. And I’m waiting for it………but it never comes, the balance is correct and well done, while I have heard this showing vocals more forward in separation, there are other added vocals which fall out farther to the sides, and even the climax at 02:14 is filled with dramatic luster, yet never any fear of too much or too bright, or too forward. What we are left with is truly balance, the balance to enjoy the music and forget which IEM is in our ears. At 02:29 there is this synthetic stand-up bass or something which goes along with the bells finding the vocals right in the middle. Again the redeeming factor is the naturalness and fullness of replay. The way of the fall-offs of reverbs, the correct Oboe tone, where this IEM truly allows you to figure out which instruments are real and which are sampled or created with synthesis……and that is more than I would ever ask an under $40.00 IEM to do.





Packaging:

The Cable:
While it's easy to shoot arrows at the included cable quality, we are not talking about a $300.00 IEM here. Therefor the cable works and is of adequate quality for the money asked.

Out and about:
Possibly the most overlooked feature here at Head-Fi will be just how valuable the Neo1 is from a simple phone. Yep, if you were to truly only use a phone with the Neo1, you have just struck solid gold. Reason being is the sound is full and possibly more correct in stature. Honestly I can’t believe it? Big stage, big imaging and most importantly note-weight. Yep…..even any worry about any 4.5kHz pinna gain has been totally smoothed out. But, what am I really getting at? Simply musicality my friends. This is singlehandedly one of the very best IEMs for phone use in recent memory? Somehow it sounds better from a phone than audiophile sources? 1st lets start with bass……..please is this really how good these are from a phone? What? Big, deep, powerful and well paced………don’t believe me? Just get a pair and see for yourself. If I wanted to join the ranks on the subway or walking, I can’t think of a better way to go? Big imaging, hefty note-weight and a fun playful signature, and best of all clarity, with nothing harsh, just making stuff sound natural and wholesome.




Conclusion:
Is there a reason to buy this? Sure it showcases the Penon/ISN sound characteristics and performs the very basics of sound reproduction well. Nothing is fake or really wrong inside of regular replay. With that said, some may find the murkier waters of the SIMGOT EW200 better or at least more forgiving. Normally this would be the place where I say that the EW200 may be better for Rock or EDM, but no……not here as Penon/ISN have really put together an IEM that (for the money) does it all. Sure the 4.5kHz peak is still there, but becomes an attribute once you really understand what the Neo1 is up to. You see this 4.5 little kHz peak is what makes the Neo1 have openness and clarity, pace and distance. This distance is created so that the bass has imaging and texture, form and character. I have spent 21 days learning about the Neo1, do you think I truly don’t know it as an IEM?

The best part is the sound, but secondary to that the build and the fit. I mean look at it, it’s gorgeous, and the wood faceplate means every build will look slightly different. It is the style of IEM that allows long listening runs due to both fit and sound. Truly I feel Penon/ISN are making a great value statement by releasing such a bargain……get yours today!

$39.90
https://penonaudio.com/ISN-Audio-NEO-1

Disclaimer:
I want to thank Penon Audio for the love and for the ISN Neo1 review sample.

Disclaimer:
These are one person's ideas and concepts, your results may vary.

Equipment Used:
Sony WM1A Walkman DAP MrWalkman Firmware 4.4mm
Sony WM1Z Walkman DAP MrWalkman Firmware 4.4mm
Sony TA-ZH1ES DAC/AMP Firmware 1.03
Electra Glide Audio Reference Glide-Reference Standard "Fatboy" Power Cord
Sony Walkman Cradle BCR-NWH10
AudioQuest Carbon USB
Samsung Phone 3.5mm output

This was not a love at first listen for me. I was expecting a lesser quality Neo5.

I was not expecting a bright mid forward set at all.

The Neo1 is not the same as its big brother and not a warm and bassy laid back IEM

Nope it's a very energetic and bassy IEM

After some initial impressions, I gave feedback to Penon and I am happy to see implemented in the final version.

Now not everyone is treble sensitive and in fact there is a whole cult of people who love brighter tunings!

Well here is a ISN for you
It has the ChiFi "Female Poison" DNA
That makes female vocals come to life.

For those of us who are sensitive to 4-5 straight out of the box The Neo1 will make your ears ring for hours.

Using the supplied Tuning kit provided a great measure of relief in that area to where knocking down the pina and bringing up the proceeded bass makes it a much better tuned IEM for my tastes.

That bieng said love this IEM in short bursts, but not something I would pick up for long grind to chiilax.

Bass is definitely the star of the show for me but the Neo1 is not just a one trick pony. Because the bass is impactfull, textured and less thick this leads well into a leaner lower mids and ultimately great vocals. Not So much for male vocals but certainly for female vocals a real treat.

Overall the mids play forward in the mix for me with the Bass catching up and Still a great amount of precieved air and extension in the tip end.

One big thing to mention was the long burn in time I feel is required to bring out the Neo1's personality 120+ before things smoothed out enough for me to enjoy even with the tuning kit.

If ypur preferred sound signature is warm and gooey the buy the Neo5 if you have a Neo5 and wanted to try a ISN with a brighter more energetic tip end the Neo1 is for you.

Overall I would have rated this one higher if not for its poor timing in the current ChiFi offerings. To elaborate on that statement new the end of the year we typically see 30-50 new sets come onto the market from established companies and names to new faces all trying to pull money out of your pockets.

In the Sub $50 scene there are tons of great tuned IEM'S with standout features and accessories even at the $25 price point we are blessed with some great ones.

Though this one is not tuned for my preferences,the Neo1 will definitely appeal to thoose who prefer this kind of tuning and for sound alone you are getting great value with a quality driver at $39.

In a sea of safely tuned Harmanish IEM's the Neo1 stands out proud and offers something different from the mainstream with the ISN name.

Marks taken off in view of current market competition and the fact that the unit needed to ship with tuning filters to fix the " Female Poison" Tuning.