1000+ Head-Fier
I’m a Believer Now
Pros: Wonderful design, relaxed but detailed sound, strong bass impact
Cons: Larger shells, meh cable, not for bright tuning lovers

I’ve always wanted to check out 64 Audio stuff for years. I was most interested when the N8 came out since that sounded right up my alley. While I didn’t have luck getting in contact with anyone before to get something to try out, I’ve always kept my eye on the 64 Audio releases. I have some reviewer acquaintances that I hold to high regards such as @Precogvision who preaches the good word of house 64 Audio :p. I took a shot at seeing if the Bloom Audio family would be willing to send something to check out. To my luck they had a Nio on hand I could check out! I jumped at the chance to review it. The Nio is a 9 driver hybrid consisting of one 9mm dynamic driver and 8 BA drivers. It comes in at $1699 here in the states.

This will be mostly a full review but I only got the IEMs, the M15 module and newer 64 audio branded stock cable/upgrade cable. So I won’t have a full unboxing or info on the sound differences between the module plugs.

Quick shoutout to @Andrew DiMarcangelo and Matthew(for the super nice letter) for sending the Nio out to borrow and review. While I always appreciate the chance to test and review products sent in from manufacturers or dealers, it never affects the rating of my reviews.

The 64 Audio Nio can be picked up from Bloom Audio at their website below.

Onto the review of the 64 Audio Nio! My personal preference is a hybrid/tribrid IEM where I get good hitting bass and have a detailed treble with decent mids. When it comes to an over ear headphone I prefer a spacious sound with a deep low end, the mids to be more forward and the highs to be a little bright with some sparkle. I listen to a lot of genres but I hover in the classic rock, blues and edm music with some rap here and there.

Gear Used​

IPhone 14 Pro Max with headphone adapter, Shanling M3X, Topping G5 and SMSL SU-9 feeding the SP400 amp.

Looks and fit​

The Nio is a good example of an industrial style shell design that can also be beautiful to the eyes. The shell is a slightly bigger and bulkier design that is a simple black shell with a silver faceplate. What makes this design unique to me is the nice blue abalone insert that they have in the faceplate. It’s rather striking and I’m very impressed by the way it looks against the silver faceplate. They also have their Apex module on the faceplate which can be swapped out for more or less pressure. If it isn’t obvious, I love the way this looks and I was able to get a comfy fit with some Spinfit CP100+ tips on my first try and I can easily listen to the Nio for longer sessions with no problems. I did end up using the W1 which is my current favorite set of tips from Spinfit, when I can get them to fit.

Isolation and sound leakage​

While I only have the M15 module on hand, it does well at passive isolation and leaks less sound than I thought it would. I would still recommend lower volumes for quiet public areas.

Packaging and accessories​

Like I said above. I didn’t get the entire Nio box or accessories but I did want to mention the Bloom Audio extras and the nice letter I received from the Bloom Audio team. I was surprised to see they still sent candy with their orders and I got a bag of skittles with the IEMs. I only received the stock M15 module, IEM shells and both a newer stock black cable as well as the 64 Audio branded silver upgrade cable. I also got a really nice letter from Matthew sending some nice words about a prior review I did a long time back so I appreciated the kind gesture!


These final impressions were done off the SMSL SU-9 connected to the SMSL SP400. These impressions are what the Nio sounded like to my ears. This was also using the W1 eartips from Spinfit. Things like ear tip selection and DAC/amp selection will produce different results and impressions vs what my ears hear on my specific gear.

I wasn’t sure what to expect but the Nio seemed to have a tuning in line with what I personally like and I can confirm it was absolutely turned the way I wanted it. Starting with the bass, It hits pretty hard and while super full sounding, it doesn't sound bloated and manages to blend well into the lower mids. It still sounds really strong so this gets a little more into bass head territory. The mids sound fairly detailed and a little more relaxed overall. It doesn’t suffer from any veiling and I enjoy the instrument presentation overall. The mids sound fast which gives it a sense of speed even if it’s somewhat relaxed/sweet sounding. The vocals are a little recessed(which I prefer) and blend into the rest of the music but I feel there is some good quality here. There is enough sharpness to female vocals that it feels more natural sounding. The treble is tame but still has good detail retrieval. I can still hear some sharpness and the decay is a little slower on things like cymbal hits. I would say this is a smoother sounding IEM with a thumpy bass overall and I quite like it.


Staging is above average with a good sense of space for an IEM. It could be due to the venting module system but I feel like things have more air all throughout the frequency range. There’s better IEMs in the staging department but this is pretty good overall. Imaging is really good if you’re not listening to anything too bass heavy. Hard hitting bass is distracting to me and I have a harder time listening for details when I get good bass thumps. I was able to pick out details and when things were located easily on normal non EDM music.


The Nio isn’t super hard to drive but will require higher volume levels on lower power dongles. I think most modern dongles will power the Nio just fine though. Especially when running balanced.

Stock cable​

The stock cable is garbage to put it nicely. While I can’t comment on cables included with newer 64 Audio IEMs, these are the old school black skinny cables. They feel like $10 cables and have the very old school “American” IEM cable look and feel that most US made IEMs come with. I also received the upgraded silver cable which I did most of the review with. It too sucks in terms of looks and feel and has an obnoxiously large 2 pin connector but it works well. It also looks like poor quality for $200 that they sold these for. Minus my complaints, I would leave these cables alone if you want utility and function over looks. They work fine and while I can’t comment on the long term durability of these or my confidence in them, I would say maybe keep a backup pair of decent quality cables on hand from another brand.

IEM comparisons​

THIEAUDIO V16 Divinity​

The V16 and Nio take similar approaches in tuning with different strengths. The Nio does low end impact/slam better than the V16 but the V16 manages the bass better and while it too can hit hard, it just sounds better controlled and less exciting. The mids are smooth on both IEMs but the vocals did sound forward and more detailed on the V16 over the Nio. Nio let more instruments come through with a slightly recessed vocal presence. Both feel fast in the mids. The treble is tame on both IEMs but the Nio sounds a little more exciting than the V16 and is a little brighter sounding to my ears. It however doesn’t quite have the same control or refinement that the V16 has. The V16 sounds more detailed and while it doesn’t quite have the same sharpness or decay as the Nio, I hear instruments with better detail and enjoyment overall. I also think the Staging and imaging is better on the V16. It has a wider stage with more precision overall. I like both and while I wouldn’t personally own both at the same time due to the similar tuning, I would keep one on hand for sure when it comes to smooth and detailed IEMs on hand that have a bass focus. If I had to choose personally, I would go for the V16 Divinity since it has a better all rounder performance.

Campfire Solaris​

The OG Solaris is newer to me but it’s been out for quite a few years at this point. It’s my daily driver however since I do enjoy using it at work. Both IEMs are designed in the US but both go for very different tunings. The bass hits much harder on the Nio and the Solaris goes for a somewhat relaxed bass that lets impact and slam come through when called for. The mids are more crisp and sharper on the Solaris but I find vocals are more forward sounding on the Solaris over the Nio. I think the Nio has a more natural/neutral sounding vocals which results in the Solaris sounding sibilant when I A/B test them. The upper mids and lower treble have a pretty sharp peak somewhere that makes the Solaris a little harsh and bright sounding where the Nio has a good balance of brighter sound with less roughness. The rest of the treble is pretty tame on both IEMs and I think both pull in about the same amount of details with the Nio sounding warmer overall and the OG Solaris sounding brighter. The staging on the Solaris is much better and I feel like it has one of the wider if not the widest soundstage I’ve heard in a bit on an IEM.Imaging is great on both but I think the imaging falls into the “holographic” type of imaging on the OG Solaris while the Nio sounds more like a standard IEM with good standard imaging. I like both but I think I would pick the Nio as it aligns closer to my personal preferences.

Amping Combinations​

Topping G5​

The G5 is my daily driver lately and I use it a lot at the office where I do a good chunk of reviewing and typing. The G5 is a favorite due to it sounding like a much bigger amp than it is. The bass thumps nice and hard via the G5 and keeps things clean but fun sounding. The mids from this pairing is a little more forward and the vocals have a better presence over the rest of the performance. The treble is very clear and adds a little extra sharpness to the Nio that I enjoy. Staging sounds a little more intimate and I feel the Nio had a wider sounding stage via my desktop amp but it’s close. A great pairing to my ears.

SMSL SU-9/SP400​

As with all my reviews, this is the setup I do my sound impressions from. I don’t think the Nio needs a desktop setup to sound its best and I achieved comfortable volumes around 30-34/99 on high gain so not bad. I do believe the big difference with this pairing was the slightly recessed vocals and the wider sounding stage.

Overall thoughts​

I always wanted to try the 64 Audio stuff and having a lot more experience with many IEMs over the past few years, I can really appreciate the Nio. I think it’s fair to say I’m a “believer” and I can highly recommend the Nio for new and experienced IEM users who like strong bass, sweet yet fast mids and detailed, yet smooth highs! Those hunting a detail monster with intense and sharp highs will want to look elsewhere however. I have quite the interest in checking out other 64 Audio IEMs in the future and look forward to seeing what they come out with down the road. Thanks for reading!!
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Agreed. I consider the Nio and U18t the 2 most satisfying 64Audio offerings and relatively delivering more bang for the buck than other models I demoed like N8, U12t, Trio, Fourte, and Fourte Blanc. I haven't heard U6t unfortunately and I expect them to end up next to Nio and U18t.



100+ Head-Fier
64 Audio Nio Mini-Review
Pros: Warm, plenty of sub-bass, harmonically rich, airy treble, capable
Cons: Technicalities fall behind a bit - likely unavoidable with this sound signature

The 64 Audio Nio is one of the newer IEMs in 64 Audio's lineup, and easily the most gorgeous. The Nio has one of the most comfortable IEM shapes I've ever tried. I listen to the Nio off a Qudelix 5K.

The sound of the Nio can be described as warm and punchy. There is an abundance of sub-bass - the dynamic driver good stuff. Mids are warm and harmonically rich. Treble is smooth, extended, and airy, but still very detailed and capable. The overall sound signature is very pleasing - terms that come to mind are enveloping, warm, relaxing.

Compared to my Solaris 2020 - the Nio is much easier to listen to for much longer. It falls behind in technicalities (soundstage, crispness) but only by a little - and I suspect this is a necessity given the sound signature the Nio attempts to achive. Overall, the IEMs complement each other excellently - bright and sharp versus warm and smooth - and though I've owned each IEM for at least half a year, I listen to them about equally.

TL;DR: the Nio is tonally pleasing and capable IEM that's just fun to listen to.
Tone and Timbre the Nio is miles ahead of the Solaris. As for technicalities I found the Solaris can project a 3d image effortlessly meanwhile the Nio has the wider soundstage especially on the MX module.
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Reviewer at
The Hybrid Dark Horse
Pros: - bass tactility and slam
- lush, thick midrange
- extremely pleasing tonality, flexibility w/ MX module
Cons: - good, but not best-in-class technicalities
- 5kHz treble peak can be fatiguing w/ MX module
I've owned the Nio for several months, so I thought I'd plug a quick review as I don't see too many for this awesome IEM on Head-Fi. You can read my full review here too.



The Nio follows an L-shaped tuning with the M15/M20 modules and something much closer to neutral with the MX module. Because I'm a dirty bass-head, much of this quick review will focus on the M15 module. With the M15 module, the Nio is a warm, gooey, sub-bass oriented IEM.

And indeed, the best word to describe the Nio's bass with the M15 module is "dirty". There's a roundness to the mid-bass' transient attack that often delves into bloat, and yet, I wouldn't have it any other way. Like so, sheer dynamic slam and texturing are present in spades in the sub-bass, making this a worthy trade-off to my ears. The Nio's midrange is thick and lush, at times obscuring macro-detail at the expense of being incredibly forgiving. Moving into the treble, the Nio is more lower-treble oriented and subdued in the air frequencies. Perceptually at least - because nonetheless, extension is ample, and like 64A's other IEMs that use the tia driver, I suspect it peaks somewhere in the post-10kHz frequencies. Make no mistake: This is an extremely tonally pleasing IEM, and all the more so considering you can swap in the MX module for an almost entirely different sound.

Along these lines, you'll want to know what the MX module does. It would be best to treat the MX and M15 modules on the Nio as separate IEMs. You can see from the graph above that it largely cuts off the sub-bass shelf, bringing the Nio something much closer to neutral. A lot of the mid-bass bloat is cleaned up, the midrange takes on a leaner presentation, and the stage opens up a good deal. Sounds pretty sweet, right? Admittedly, though, it's not really my speed. Note the Nio's 5kHz treble peak; it gets brought to the forefront by virtue of less bass, lending the Nio to a more fatiguing, if not "clean" listen.

Intangibly, the Nio is a solid contender, although decidedly not best-in-class. The transient smoothing and warmth serves to clean up a lot of the BA timbre. Nio's imaging is more intimate, maintaining solid positional cues and moderate solidity of the image projected. As noted above, you can use the MX module to open this up more. I still would not qualify Nio as the oft-misused word "holographic" or anything of the sort. Macrodynamic ability is good; the Nio is surprisingly dynamic, although noticeably more sluggish than the U12t.

And there you have it. I'm still on the fence about owning both the U12t & Nio simultaneously, and the Nio would probably be the first to go. Nonetheless, the Nio is unmistakably an excellent IEM, one that I found worthy enough to include in my fairly small collection.


twister6 Reviews
Headphoneus Supremus
The Natural Abalone!
Pros: natural detailed tonality, powerful bass impact (depending on module selection), interchangeable APEX module, LID tech, new packaging and leather case.
Cons: not a typical tia-driven treble, benefits from a cable upgrade.

The product was provided to me free of charge for the review purpose in exchange for my honest opinion. The review was originally posted on my review site, and now I would like to share it with my readers on Head-fi.

Manufacturer website: 64audio. Available for sale directly, as well as various retailers like Bloom Audio.


In Matrix, Neo had a choice between red pill and blue pill to pick his destiny. In audio-Matrix, Nio, the new protagonist from 64 Audio, is faced with a choice of different APEX “pills” to decide its sound tuning path! Maybe this story sounds a little too melodramatic, and I’m sure some might even question, how is this any different from other 64 Audio releases with interchangeable APEX modules? Well, for starters, this is 64 Audio first universal hybrid release where, unlike Fourte and Trio, you can remove and replace the module to give you more than just fine-tuning of the sound.

Ever since my review of N8 from two years ago, I was hoping 64 Audio will consider universal version of this hybrid CIEM. And it looks like my wishes came true! Teased earlier this year at CanJam NYC, there were a few noticeable hints, like a placeholder name of “K9” suggesting 9-driver design and a shell with DD venting port. When I found out the official name of this IEM, it made a perfect sense to me: Trio is Three-driver hybrid, Fourte is Four-driver hybrid, Nio is Nine-driver hybrid. But, is Nio just a universal version of N8 or more? Let’s find out in this review of 64 Audio latest release.


Unboxing and Accessories.

Nio arrived in a brand-new packaging box design, a step up from their previous universal releases of U18t, Fourte, U12t, and Trio. After a dozen of 64 Audio IEM/CIEM reviews, I’m used to either their small compact no frills boxes geared toward musicians or larger consumer friendly boxes with fancier presentation, all with the same custom plastic organizer case. Nio seems to switch gears to highlight its beautiful Blue Abalone faceplate design by having a matching artwork around the packaging box. You still have a picture of IEMs popping out in 3D from the front and a very detailed design diagram and description of features on the back.


Inside, everything is secured around the foam insert with cutouts for Nio with a cable, pockets for M20 and new MX APEX modules (with M15 already in the shell), and a new leather hockey puck shaped case with a company logo imprinted on the cover. I guess I was more surprised with a case than anything else. I’m sure 64 Audio is not discontinuing their original organizer case which many musicians will find quite useful and secure. But with Nio having more consumer-oriented appeal, this round leather case adds a nice touch of luxury to the storage.

Other included accessories, stored inside of the case, a cleaning tool, shirt clip, a set of silicone eartips (S/M/L), a set of TrueFidelity foam eartips (S/M/L), and dehumidifier capsule. Plus, you will find a traditional 64 Audio round sticker, and a product manual with useful info about care & maintenance, handling detachable cable, using APEX module, volume safety advisory, and warranty info.

At the moment of writing this review, 64 Audio announced a fine-tuning of their logo. It is not a drastic change, just a refresh. But still, please keep this in mind, my review sample has the original older logo.



64 Audio stock cable uses ultra-low resistance flexible non-microphonic silver-plated copper (SPC) wires which come in either Professional or Premium versions. Sometimes it creates a confusion because people see different cable plugs/connectors in pictures without realizing it is still same wires. The main difference between these cables is in hardware.

Professional has a more basic 2pin connector mold which is compatible with recessed and non-recessed sockets and has red/blue indicator dots for right/left shells, memory wire, heat-shrink y-split and clear tube chin slider, comes in black or white rubbery shielding with either 48” or 64” length, and has 3.5mm only option inside of a plastic right angled plug. Wires are inner-twisted between plug and y-split and then twisted in pairs going up. It is a cheaper looking cable and it comes standard with all 64 Audio CIEMs and also compatible with non-recessed universal models.


Premium cable, which uses the same wires, has a higher quality hardware with non-recessed angled 2pin sturdy connector and L/R letter indicator, memory wire, 64 Audio branded plastic y-split and a plastic chin-slider, and uses a more premium brand name plug with options for 2.5mm, 3.5mm, and 4.4mm termination in either straight (2.5/4.4) or angled (3.5) housing, and comes only in black rubbery shielding and 48” length. Wires are inner-twisted between plug and y-split and then twisted in pairs going up. These cables come standards with universal models, such as Fourte/Trio/U18t/U12t and Nio, and looks more premium.


When Nio was originally launched during the summer, 64 Audio had a promotional deal for their new Premium Silver Hybrid cable, bundled free with Nio orders. The people who received a free bonus Silver Hybrid cable also got Professional stock cable, while afterwards all Nio orders come with a Premium cable. Also, Premium cable only comes in stock with 3.5mm termination, and I wish they would have offered an option for termination upgrade.

Furthermore, as I was working on my review, 64 Audio added an option for IPX connector in addition to 2pin connector. Again, this is only an option for CIEM models when building these monitors and having a choice between 2pin or IPX (new smaller and more secure connector which resembles mmcx, but has a much higher quality).

And speaking of the new silver premium cable, let’s find out more about it.

64 Audio Silver Premium cable.

While this new cable is called Silver Premium, in reality it has a Silver alloy core surrounded by 200 Silver-Plated Copper strands. Basically, this is 26 AWG gauge ultra-low resistance 4-wire multi-core structure Silver plated OCC and Silver Alloy. It even uses a premium audio grade solder to make sure signal path is pure and has low resistance. So, this is not a pure silver cable but rather a hybrid of Silver and SPC material. I think this design was chosen to reduce the wire resistance without making the gauge thicker or doubling the number of conductors (from 4 wires to 8 wires).

It is a very nice-looking cable, very soft and flexible, non-microphonic, braided between plug and y-split, with all the same hardware as 64 Audio Premium cable, including non-recessed 2pin angled connector mold, memory wire (which I personally can’t stand and removed right away), 64 Audio branded y-split, plastic chin slider, and the termination plug of your choice, depending on availability (since at the moment of writing 4.4mm wasn’t available).

Of course, it was no-brainer when this cable was offered as a free bonus. But as an optional accessory, I will go over the sound benefits of this cable and a few others further in my review.



The exterior design of Nio is like a crossover between Trio and U12t. In general, their shells have a similar shape as other 64 Audio universal IEMs, though, surprisingly, Nio is closer to a “leaner” inner shell of U12t than more bulbous Trio. Plus, Nio combines the hybrid design (Fourte/Trio) with a larger DD vent and APEX socket (U18t/U12t) without a need for a small pinhole vent for internal module (like in Fourte/Trio). Also, unlike Fourte/Trio, the DD vent is facing the back of the shell instead of the front because APEX module is in the way. In this regard, based on the identical driver config, Nio is aligned with N8.

The shells are all metal with the inner part having a glossy black finish while the outer faceplate part having a shiny chrome finish with a beautiful Blue Abalone inlay. This is by far my favorite 64 Audio universal faceplate design, and Blue Abalone gives Nio custom-like IEM finish. The nozzle is relative long, more typical of 64 Audio multi-BA rather than hybrid models, and, unfortunately, there is still no extra lip at the tip to help eartips from sliding off. I mean, with majority of my eartips I don’t have an issue since there is a secure grip, but some silicone eartips can slide off. 2pin socket is non-recessed like in other universal 64 Audio IEMs. And you have 64 Audio logo symmetrically on each faceplate, and L/R, model and S/N printed on the inner part of the shell.


Inside the shell you have a hybrid design with a 4-way crossover partitioning 9mm low Dynamic Driver (DD), 6 mid BAs, 1 high-mid BA, and 1 tia high BA – with the total number of 9 drivers. Balanced Armatures (BA) are typically self-enclosed with a single opening port, while you can think of tia as an open BA driver where one of the enclosure walls is removed, to enable direct-radiating of the inner diaphragm which no longer has a 4-wall confinement. Tia driver is usually positioned in the nozzle, next to the grill since it has to be closer to your earcanal. As a result, Nio doesn't have sound tube bores going to the nozzle, and instead has a mesh cover to protect from wax build up.

Another tech included with Nio is their Linear Impedance Design (LID) of crossover where despite a low impedance (6ohm), Nio should be compatible and sound the same when paired up with different sources, regardless of their output impedance.


The fit.


Sound Analysis.

I analyzed Nio sound performance paired up with P6 and LPGT while playing a variety of test tracks, such as Agnes Obel “The curse”, Sandro Cavazza “So much better” (Avicii remix), C-Bool “Never go away”, Ed Sheeran “Shape of you”, Alan Walker “Darkside”, Galantis “Hunter”, Iggy Azalea “Black widow”, Indila “Boite en argent”, Dua Lipa “Love again”, Counting Crows “Big yellow taxi”, David Elias “Vision of her”, and Michael Jackson “Dirty Diana”. Due to a hybrid design with a dynamic driver, I gave Nio plenty of burn in time, and started analyzing the sound after about 100 hrs of standalone playback. I used SpinFit eartips in my analysis.

Similar to the original N8, Nio has a smooth natural fuller body detailed tonality with a more laidback presentation. The sound signature varies depending on which module you are using and can go from L-shaped (M20), to more balanced (M15), and even borderline mid-forward (MX). When going between the modules, the tonality of mids/vocals is consistent, but their presentation will change due to variation in bass impact. Also, different modules with their corresponding isolation characteristics will have the effect on treble sparkle and airiness.

Starting with a technical performance of Nio, a soundstage expansion in particular, I hear it to be wide and deep with a natural sense of spacing, not exactly 3D holographic or too intimate. It has a good balance of a realistic width and slightly more depth, especially placing vocals a little further out of your head. The imaging is good where I find it easy to pin-point instruments and vocals with each having a relatively convincing positioning in space.

I do hear a good level of layering and separation of instruments and vocals, keeping everything clear and not congested, but due to a natural tonality, fuller body, and less airiness, there is not as much sense of "air" between the layers, creating a more laid back natural presentation of the sound with a linear transition between bass and mids, even when selecting a module that will elevate bass impact. There is definitely a sense of tuning coherency where it doesn’t even feel like you are listening to a hybrid.


APEX modules, as well as ATOM XL modules (by FirAudio, similar design idea and size), do have a noticeable impact on the sound tuning. While they mostly affect bass response per my measurements, what you see in the graph doesn't always reflect what you actually hear because the change in bass affects the overall signature and also changes the perception of mids and even the treble, as well as other technical aspects of the tuning. But as I mentioned before, even with these changes, mids/vocals still remain very natural, organic, soulful, musical, and still detailed, while treble has a clear non-fatigue level of sparkle and moderate airiness, especially when using stock cable.

My measurements of all the modules:

Since there is a noticeable variation in sound signature going between modules, I will break it down how I hear Nio with various APEX and ATOM XL modules. Please, keep in mind, Nio already comes with M20, M15, and MX modules. ATOM XL modules (N17, N15, N13, N0) are fully compatible with APEX and offer their own sound variation which I would like to describe as well in this review.
  • Nio (M20) - close to L-shaped sound sig with a natural musical tonality, big bold bass with a lifted sub-bass rumble, rounded punchy mid-bass with a longer decay, fuller body natural mids with above neutral lower mids and more organic yet still detailed upper mids, and very natural yet still well defined treble with a moderate sparkle and airiness.
  • Nio (N17) - the sound is more balanced now, still on a warmer more natural side, but with sub-bass attenuated by about 3dB, the bass impact has a more balanced weight which gives mids more room to shine. Mid-bass still has a longer decay which blends in nicely with fuller body lower mids without causing any muddiness, but now upper mids opened up more with a little more forward presentation and some improvement in detail retrieval. I even hear a touch more sparkle/air in treble, but I think it is all due to a more balanced sound sig.
  • Nio (M15/N15/N13) - these modules have a similar effect where I hear a slightly less mid-bass impact in comparison to N17 and also a more open/wider soundstage with a little more sparkle in treble. Actually, when it comes to soundstage expansion, N15 width is closer to N17, while M15 and N13 have a similar wider soundstage, even wider than N15. Otherwise, the rest of the performance is similar between these three, having a more balanced signature, more forward presentation of mids without vocals being as laidback as with higher isolation modules, and more airiness in treble which now also helps with layering and separation of the sounds.
  • Nio (N0) - this module helps you get the most from mids/vocals while still having a good amount of sub-bass rumble and a little faster mid-bass punch. Bass is above neutral and provides a good low end foundation for the sound, but it is not the focus of the tuning, while upper mids are more revealing now, more layered, and have some improvement in retrieval of details. Treble is similar to M15/N13, with the same amount of sparkle and a little more airiness. Another thing which could be a result of improvements in upper mids, the perception of soundstage is a little wider now.
  • Nio (MX) - one might ask why I did not combine and analyze MX and N0 together since they both supposed to have 10dB isolation with a similar sound effect? In my opinion, MX has a much lower isolation since I hear its bass response to be more attenuated in comparison to N0 and the rest of the modules. But I think there is a silver lining to this since this drastic sound change creates a different signature to contrast other modules. With MX bass sounds neutral and very linear. Not exactly flat, there is some punch left in mid-bass, but it is relative attenuated, putting a spotlight directly on the mids. Lower mids are still above neutral and have a little bit of body left in there, but no longer have the extra thickness courtesy of longer mid-bass decay. Mids/vocals are more layered, more revealing, even more micro-detailed, and they are more transparent now, with a lot less coloring. Treble also has more sparkle, not harsh or splashy, but noticeably more present with air and further extension.
Personally, I do like to hear the bass but don’t need to “feel” it like with M20 which brings up sub-bass rumble, thus N0 suites my taste better. With that module I also get benefits of more mids/vocals focus and a little more air in treble, relative to N17/M15/N13. And at the same time, N0 still has more weight in bass and a more natural coloring of mids when compared to MX.

MX, N0, N13, N15, M15, N17, M20

Eartips selection.

The selection of eartips is crucial with any universal in-ear monitor and will affect the sound, especially the bass impact depending on the seal and the soundstage depending on insertion depth. Due to a large opening of my earcanals, I usually go for the largest size eartips to get a better seal. In this comparison I was using Nio with N0 module and stock cable. Please, keep in mind, these impressions are subjective and relative to my ear anatomy which affects how I hear the sound.

Spinfit - natural balanced tonality with deeper bass impact, organic mids/vocals, and natural well defined treble.

Final Type E - very similar to Spinfit, except soundstage width shrinks a little, becoming narrower.

AZLA Sedna - very similar to Spinfit, except soundstage depth is a little more out of my head.

stock 64audio Foams - bass impact was softer, slower, and slightly attenuated, and treble was also a bit attenuated; the sound had more focus on mids.

Symbio F - a very balanced sound with mids having more focus and treble gaining extra sparkle, and even soundstage being a little wider and more holographic.

Symbio F and Spinfit were my favorite eartips to use with Nio. During testing and comparison while constantly taking Nio in and out of my ears, I preferred Spinfit since Symbio F is a slower release foam, but during extended listening sessions I switched to Symbio F since I was not in a rush and could wait for it to form its shape inside my ear.


Cable pair up.

I’m aware that some people don’t believe in cables and have very strong opinions about it. It’s not my intention to trigger the argument, and instead I would like to share what I hear during my testing. What makes sense to me, a metal wire is a material with physical properties of resistivity, conductivity, purity, and unique geometry, all of which put together act as a filter between your source and headphones. Variations of these physical properties can affect the conductivity of analog signal, resulting in a sound change, from a subtle to a more noticeable level. If the talk about cables upsets you, please skip this section; otherwise, you can find more details in my original Nio review on tw6 site.


The comparison was done using Nio with a stock cable, SpinFit eartips, and P6, LPGT, and SP2k SS sources, volume matched in every comparison.

Nio (M15) vs 64 Audio N8 (M15) - to start off, N8 has a more holographic 3D soundstage while Nio is wide/deep but not on the same holographic level. Considering the same APEX module used in this comparison, Nio bass response has a little more impact, in both sub-bass rumble and mid-bass punch. Also, Nio bass is a little tighter due to a shorter decay. With mids/vocals Nio is smoother, a touch warmer, and with less forward presentation which positions mids a little more out of your head, while N8 has mids more forward and closer, even a little more revealing and transparent. Another noticeable difference is in treble where Nio is smoother and more natural while N8 is brighter and with a little more sparkle. Despite having the identical driver config and spec and while using the same cable and the same APEX module, based on what I'm hearing these don't sound identical. They are not night'n'day, but each one definitely has their own sound characteristic with unique fine-tuning.


Nio (M20) vs EE Legend X - every time I bring up the bass, my readers ask about LX, so there is no way to avoid this comparison which only makes sense with Nio in max isolation w/M20. With M20 Nio bass impact goes up, while soundstage shrinks, and as a result LX soundstage is wider. With bass itself, while Nio w/M20 has a healthy bass slam, it is still not on the same ear-bleeding bass head level as LX, but I still think Nio w/M20 can put a smile even on demanding basshead. With mids/vocals, they quality/tonality is relatively similar, but their quantity and presentation are very different. LX mids are pushed back and a bit recessed, while Nio w/M20 mids/vocals are more forward and more revealing. With treble, LX has a little more sparkle while Nio w/M20 treble is smoother and more natural.

Nio (M15) vs 64 Audio U12t (M15) - relative to the same M15 module and stock cables, I hear soundstage expansion to be quite similar in this comparison. With bass, Nio has deeper and more elevated sub-bass rumble, not by a lot but it is more noticeable. The impact of mid-bass is a little bit lower in U12t, but overall quality of the bass is very similar, just scaled down in U12t. Relative to Nio, lower mids are closer to neutral in U12t while Nio has a fuller body. Upper mids/vocals are similar in tonality and sound a little more forward in U12t, perhaps due to less bass impact which brings vocals more forward. Nio treble is smoother and sounds more organic relative to U12t treble being crisper and brighter, especially in lower treble. Both are relative balanced tuned IEMs where Nio is smoother and with more focus on bass while U12t is more revealing due to more focus on upper mids and lower treble.

Nio (M15) vs 64 Audio Trio - the soundstage here is similar as well, perhaps with Trio being just a little bit wider due to more airiness and treble sparkle. Bass impact and extension of Trio comes very close to matching Nio w/M15 module. Actually, Trio bass sounds even more articulate because of a deeper separation from lower mids which gives it more control, while Nio bass sounds more analog and rounder, like a floor-standing speaker. Mids between these two are quite different. Trio lower mids are neutral and thin which gives more contrast between the bass and its colder upper mids/vocals, all this taking away from the natural body of the vocals. Nio lower mids are fuller, with more body, and upper mids are more natural, warmer, more organic. Treble is where you will find another big contrast where Trio is a lot brighter and crisper, while Nio is quite the opposite, being smoother and more reserved. With an exception of similarities in bass, these are quite opposite in everything else where Nio is more balanced and warmer with more emphasis on low end while Trio is v-shaped with more emphasis on bass and treble.


Nio (M15) vs FirAudio M4 - this is a very interesting comparison because M4 tuning is somewhere between U12t and Trio, bass similar to Trio while mids/treble similar to U12t. Comparing to Nio, the soundstage is close, though added sparkle in M4 treble gives it a wider perception. Bass is very similar to Nio w/M15, from a deep sub-bass rumble to a punchy mid-bass impact. The only small difference is Nio sub-bass w/M15 is a touch more elevated. Mids have a lot of similarities, though some differences as well. Nio lower mids have more body while M4 is not body-shy, just a little closer to neutral. Upper mids are more forward and brighter in M4 while more natural and smoother in Nio. With treble, Nio is also smoother and more organic while M4 is crisper and brighter, similar to U12t comparison, but not as bright/crisp as Trio. Here, it will all depend on how you like your upper mids/treble. If you want it more revealing and with more sparkle, M4 is a good choice, while more natural, musical, smoother is where Nio stands out.


Nio (M15) vs Campfire Audio Solaris '20 - I'm sure many will be curious about this comparison as well. To start off, Nio soundstage is wider, while both have a similar depth. Regarding tonality and considering M15 module, Nio bass slam is a lot more powerful with deeper sub-bass and more elevated mid bass. Even when I go down N13 and N0 modules, the bass of Nio still has more sub-bass rumble, while mid-bass punch evens out with 10dB N0 module. Mids are a little leaner and more transparent in Solaris due to less body in lower mids, while Nio has fuller body and more organic mids/vocals. Nio treble with M15 module is smoother relative to Solaris treble which has more sparkle. Going down in isolation modules, to N0, treble starts to get closer, but Solaris still has more sparkle and a little more air.


Pair up.

In each source pair up, I was using a stock Premium cable with balanced termination to keep everything stock for consistency. Nio is easy to drive considering its 105dB sensitivity which might need only a few extra volume clicks. Also, due to its LID tech, Nio low 6ohm impedance didn’t seem to cause any issues with different output impedance sources. Also, I didn’t hear any hissing.

Lotoo PAW Gold Touch (LPGT) - natural balanced tonality with deeper bass impact, organic mids/vocals, and natural well defined treble.

A&K SP2000 SS - deeper bass impact, more forward mids, and noticeably crisper treble.

Hidizs AP80 Pro - a little brighter mids and treble, actually treble was quite crisp in this pair up.

iBasso DX160 - more holographic soundstage, deep bass impact, a little brighter mids, natural well defined treble.

Hiby R6 - despite 10ohm output impedance, this is a perfect example of LID at work! The output impedance of the DAP didn't affect the signature/tonality as much. I still hear a natural balanced tonality with a deeper bass punch, natural resolving mids, and treble with extra sparkle.

Cayin N3 Pro - tube output does Nio a great justice with a more analog smoother tonality, still a deep bass impact, natural detailed mids/vocals, and natural well defined treble.

Hiby R8 - natural balanced tonality with a fast bass impact, natural detailed mids, and natural well defined treble. I enjoyed this pair up with Turbo mode on which gave bass faster speed and mids a little more resolution.

Luxury & Precision P6 - very natural organic tonality and a balanced signature. Deep punchy bass, organic soulful vocals, and natural well defined treble.



Ever since publishing my N8 review, I always felt this IEM was underrated and didn’t receive as much attention as it deserves. Maybe because it was marketed as IEM for musicians by musician which alienated some audiophiles, or maybe because it was tuned to sound more natural and less micro-detailed, plus some people are not ready for “custom” commitment yet. Whatever it was, I don’t want to speculate, but I was genuinely happy to see Nio released as the universal alternative to N8 with the same driver configuration and a similar tuning.

Actually, despite having identical driver config and similarities in tuning, N8 and Nio still have a slightly different sound characteristics with its own unique fine-tuning. Sure, we are talking about Custom fit vs Universal fit with a seal controlled by eartips selection. But even if we take that into consideration, I still found Nio to have a bass with a better control and a tighter punch, mids/vocals with fuller body, and more organic non-fatigue treble. It doesn’t make one better than the other, but rather will be a matter of a personal sound preference.

Plus, access to APEX/ATOM XL modules gives you a chance to fine tune the sound further. The change in this fine-tuning could go from a subtle to a more noticeable, depending on a module and your subjective hearing perception. And on top of that, module itself relieves the air pressure and fatigue during extended listening session or at higher listening volume. But at the end of the day, you are the one in control of which pill you are going to take, red, blue, or abalone to get to your next sound destination!
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Eddie C
Eddie C
2 pin iems especially at this price point should use recessed sockets. If the cable connector is bent by accident and the pins snap off, it is a bad time. What makes it even more of a no brainer are the stock cables are recessed socket compatable.
Are you planning to review the Luxury & Precision P6?
Amazingly thorough and comprehensive review. I am going to try these tomorrow at CanJam SoCal 2022. Can't wait.