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.
Returned about an hour later and it sounded great! Will give it about 100 hours of break in.