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Custom In-Ear Monitors (CIEM) Review Previews

Preview information available:
Lime Ears LE3 & LE3b custom in-ear monitor
Sneak peek bass ratings for select CIEMs
Custom Art Music One custom in-ear monitor
Rhines Custom Monitors Stage 3 custom in-ear monitor
InEarz IE-P250 custom in-ear monitor
Minerva Mi-Performer & Mi-Performer Pro custom in-ear monitors

I am currently quite backlogged with the sheer number of review units I have as well as my time being divided among different tasks, so I have decided to write some brief summaries of the custom in-ear monitors I have received but not yet reviewed.  Make sure you take the previews with a grain of salt, as the true findings come from comparison listening as well as finding good and bad source matching.  Please ask your questions in the comments below.

See the custom in-ear monitors review list for previously reviewed products.


Lime Ears LE3 & LE3B

Lime Ears LE3 & LEb custom in-ear monitors

Lime Ears LE3 vs. Lime Ears LE3B: The bass version of the LE3 (LE3B) is has a different tonality and slightly different presentation to it compared with the regular LE3, as the regular LE3 is slightly brighter and overall clearer. Soundstage presentation is similar in size and space, but the presentation is slightly different, with the LE3b being a bit more mid-forward and having slightly less presentation depth and a bit less width while the LE3 has slightly more focus within the presentation. Transparency is similar, but the LE3 has better coherence across the frequency spectrum, specifically from the midrange on up. Detail levels, resolution, and note capability are similar between the two, but the LE3b sounds more dynamic due to the additional bass punch and slightly faster bass attack speed, even though the bass note sustainment is equivalent. The LE3 is more forgiving even though it is slightly brighter due to a treble peak with the LE3b.

The LE3b is obviously more bass enhanced than the LE3, providing a boost throughout the entire lower spectrum in comparison. The LE3 still has good extension and ability to sustain notes, but since there is less emphasis, there is less overall sustainment. The midranges are close and similar, but the LE3b has a bit more mid-forward presentation in comparison even if the upper midrange isn’t as prominent as with the LE3. The tonality of vocals is a bit more throaty with the LE3b, which sounds more natural with male vocals while the LE3 sounds more realistic with female vocals. While the LE3 is slightly brighter than the LE3b, there is a peak in the LE3b treble that isn’t present with the LE3 resulting in the LE3 upper midrange through treble region sounding more natural and even from top to bottom.

The LE3 and LE3b provide two different flavors, both with their own strengths. The LE3 is more neutral and natural due to a more even frequency response from top to bottom, yet is still very capable. The LE3b has a richer and more exciting presentation with great performance given the price range. I would choose the LE3 for female vocals and most acoustic music while I would choose the LE3b for male vocals and electronic music. Two very capable choices for a good price.

The LE3 is now available with a switch that allows changing between the regular and bass sound signatures.

Lime Ears LE3 with switch

Lime Ears LE3 with switch


Preview of bass ratings for select CIEMs.  The score in the CIEM table is calculated from many different performance aspects of each unit.  The below table is a preview of two of those factors, bass quality and bass note sustainment, called rumble.

Manufacturer Model Price Bass
Quality Rumble
Spiral Ear SE 5-way Reference $1,650 95 96
Hidition NT-6 $1,200 96 80
Hidition NT-6 pro $1,250 100 93
Ultimate Ears Personal Reference Monitor $1,999 98 60
Unique Melody PP6 $2,280 93 94
Heir Audio 8.A $1,200 80 92
JH Audio JH16 Pro $1,149 97 91
Dream Earz aud-8X $865 83 85
Lime Ears LE-3b $700 80 75
Lear LCM-5 $945 75 60
Ultimate Ears In-Ear Reference Monitor $999 70 50
Ambient Acoustics AM4 pro $499 75 70
Dream Earz aud-5X $565 85 88
Wan Xuan (Beat Audio) wx i9pro $619 60 98
Thousand Sound TS842 $540 90 95
EarPower EP-10 Plus $1,000 80 100


Custom Art Music One review preview (review is still a work in progress)

Disclaimer: My review is done in a comparative way using similarly priced IEMs and/or CIEMs for perspective and to determine performance.  In this review I try to accurately portray the product under review, presenting strengths and weaknesses, the sound signature, characteristics, and technical performance as opposed to providing flowery dialog of performance without perspective.  My ultimate goal is to enable you to make an informed decision about what product is right for you.  Take the review as a critical look at the product and not a sales pitch or marketing fluff.  I believe gear should be selected based on the sound signature you want and/or the specific use, not solely on technical performance or unsubstantiated hype.  Here are some quick references for more information: My review technique, Thoughts on reading a review, Custom IEM information

The Music One received 100+ hours of burn in as is customary before I do my serious listening.

Bass: Being a single balanced armature driver, the bass isn’t expected to compete with dynamic driver earphones, or multi-BA earphones, and it doesn’t.  What you do get is quite good bass for a single BA driver CIEM.  The bass gives a sense of depth and power, even if it ultimately falls short of providing that power, it still lets you know there is something there while most single BA IEMs I have heard don’t recreate any of the sensation.  What is there is warm and liquid, not possessing too much detail, but never leaving a sense of lack.  There is plenty of bass for many tracks that aren’t bass heavy with pounding, reverberant bass.  Given the price, the bass is very well done.

Midrange: While I would say there is a very nice balance to the Music One, the midrange is the focus of the sound, and it has a nice blend between thickness and clarity.  Comparing with the similarly priced ER4S, the Music One presents with more detail and yet also is more musical.  The midrange is on the mid-forward side and the presentation space isn’t extremely large, at least unless the FSM-02 V2 amp is used, which really synergizes will with the Music One.  Integration from top to bottom of the frequency spectrum is well done, and the overall midrange performance is excellent.

Treble: The balance of the treble with the rest of the spectrum is excellent, as the Music One is brighter than the SM64, except in the upper-most registers, and not quite as bright as the ER4S.  This is combined with a note decay that very natural, providing a much more musical experience than the typical analytical experience of BA drivers in this price range.  Again, well done!

Presentation: Balance and musical come to mind when I listen to the Music One.  The balance across the frequency spectrum and the coherence are both very good, excellent in fact.  Sure, the presentation is a bit on the mid-forward side, but there is still a nice balance both above and below the midrange that allow the headphone to stand back and let the music take over.  It does this in a bit of a different way than usual as the Music One isn’t the most transparent headphone I have heard, but the balance and combination of balance and excellent note decay deliver exceptional results.

While the soundstage presentation isn’t the largest, it is well proportioned and when paired with a synergistic amp, can impress.  The weaknesses come with very fast music and/or complex tracks.  While the Music One isn’t slow, it doesn’t have the dynamics and impact of a faster presentation of many of the more analytical presentations I have heard, although all at higher price points.  Complex tracks can become a bit more simplistic that more expensive products, but at least they don’t really get congested.  Still, given the price and looking at the positives, the Music One has a presentation that competes with the big boys from a musicality standpoint.



Etymotic ER4S: With a similar price* and both using single balanced armatures, the ER4S and M1 are true competitors.  The ER4S has a more laid back presentation than the M1, which gives a bit of a focus to the midrange in comparison as well as better depth of presentation, providing a more enveloping sound.  Instrument separation and placement of the M1 are a bit better than the ER4S, but the two biggest differences between the competitors is the note decay and bass presentation.  The M1 presents notes in a more natural way with a longer decay when necessary along with a larger difference between loud and quiet notes within the presentation.  The bass presentation, as well as the treble presentation, is affected most by this note decay difference as the M1 is more reverberant and powerful sounding in comparison with the brighter and more analytical ER4S.  The more natural note decay of the M1 leads to better transparency and tonality while only slightly trailing in clarity to the ER4S.

Bass depth and power are more prominent with the M1, being able to provide a somewhat convincing bass experience, especially when compared with the ER4S.  The difference in warmth can be significant depending upon the track, and the entire bass region is more capable of adjusting to thicker presentations on the M1.  The midrange of the M1 is more musical while being a bit more forward, and the difference in presentation leads to the M1 being more musical in comparison to a presentation that seems more sterile and analytical.  The brighter ER4S is also harsher and less forgiving in the treble region due to a quicker note decay, which doesn’t recreate the shimmy or slow decay of some instruments, especially in comparison with the M1.

The ER4S and Music one are both capable performers, but the M1 presents music in a more organic, realistic, and musical way.  The ER4S is great for music analysis, but is limited due to the quickness of the note decay.

* Aside from the additional cost and process of getting a custom IEM made vs. just buying the universal fit ER4S, but I need to use foam, which will add cost over the lifetime of ER4S use.

Alclair Reference: While pricing isn’t too close, it is closer the closest in price of any of my current CIEMs.  The Reference was designed with the name in mind and immediately it has a more analytical nature to it with a more laid back, spacious presentation and better kick down low.  What the M1 does is present in a more organic, smoother way that simply sounds more musical.  Technically, the Reference has a larger space with better instrument separation and is more detailed with better articulation of that detail.  Transparency, dynamics, clarity are better with the Reference, but the M1 is more coherent and forgiving of poor tracks.

While the M1 isn’t lacking bass, the difference between the two is fairly large as the Reference has more punch and depth to go along with more warmth.  The midrange of the M1 is much more closed in yet more coherent, and while it doesn’t sound as open, it does sound quite smooth and enjoyable.  The upper treble is similar, although the M1 is a bit more up-front while the treble of the Reference is slightly more prominent.  Quality wise, the M1 treble smoothness and note decay are more musical vs. the analytical and more detailed Reference.

Not really competitors due to price points, these two offer different benefits with the M1 offering an organic, musical experience while the Reference is more detailed and analytical with better technical capabilities.


Rhines Custom Monitors Stage 3 custom in-ear monitors The Rhines Custom Monitors Stage 3 is a relatively mature design by Compact Monitors, and the company split into Rhines Custom Monitors and Vision Ears. My Stage 3 I has a mirrored face plate with excellent fit and finish.  The case is something different than is typical, with a nice look and feel to it.  Sonically, the Stage 3 has a neutral sound with some added warmth reminiscent of the Logitech Ultimate Ears In-Ear Reference Monitor (IERM), but with a warmer, more bass heavy, and forward presentation.  Both are very similar in the treble region, but the IERM is more open sounding while the Stage 3 is more coherent and immersive.  They both have their strengths and it comes down to what you want from the presentation as well as your location.

The Stage 3 is on the smoother side and not ultra-revealing like other reference monitors, including the Hidition NT-6, but it is also warmer than the NT-6.  The overall Rhines sound is a warmer, smoother, more organic and euphoric sound as I found out in a tour of Vision Ears demos of the entire lineup, which also includes the Stage 2 and Stage 4.  With poorly mastered tracks, of which there are many, the Stage 3 treble can sound a bit, well, annoying, especially when I am listening for issues. This is a good quality for a reference monitor and the IERM shares the same trait while the NT-6 is brighter even though it doesn’t come across quite as harsh.  While the treble has similarities to the IERM, it is something I can easily get used to when I am not paying attention to it, and less troublesome than the IERM in general.

So far, the Stage 3 has been very enjoyable with warmth, detail, and a spacious presentation that is immersive.


InEarz IE-P250The InEarz IE-P250 is an affordable dual-driver custom in-ear monitor made in the US for $295.  The sound is balanced with a slightly mid-forward presentation that is never offensive and offers quite good performance for the price.  While extension on both ends isn’t the greatest, it still has a very pleasant sound that would be expected of a top performer in this price range.  It is easy for me to listen to the P250 for extended periods of time, which I can’t say for all my lower cost CIEMs due to my snobby ears that are used to the higher end products :).  I still have yet to compare it with the vast majority of my lower cost (sub-$500) collection, but I am expecting very good performance from what I have heard.


Minerva Mi-Performer & Mi-Performer Pro custom in-ear monitors Minerva Mi-Artist Pro & Mi-Performer Pro: Minerva has been making hearing related products for over half a century and got into the CIEM game several years ago with the Mi-3.  They recently updated their lineup, replacing previous CIEM products with the Mi-Artist Pro and Mi-Performer Pro.  The Artist Pro is a dual driver in an acrylic shell with detachable cable while the Performer Pro is uses the same dual balanced armature driver housed in silicone.  The cables are different, but both nice.

As far as fit goes, the Mi-Artist Pro acrylic shell is the tightest fitting acrylic shell I have that doesn’t cause pain or discomfort, except when removing.  This CIEM does best with a push-in insertion method vs. a twist-in, and especially during the removal.  The Performer Pro also fits snugly, but isn’t quite as tight.

Sonically, they are quite different than the Mi-3, with a more forward overall presentation and a good deal more bass capability.  The Artist Pro and Performer Pro share a mid-forward presentation, but the Mi-Performer Pro outperforms the Mi-Artist Pro in bass extension and capability while the Mi-Artist Pro has better dynamics, treble extension, and treble quality.  The Performer Pro midrange is more forward and also resolves more detail than the acrylic shelled Artist Pro.


by average_joe

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