Rank #8: Ultimate Ears UE18+ Pro


The UE18+ Pro’s coherent signature begins with its bass. In terms of impact, it’s a relatively neutral bass. But it’s a very natural sounding bass. Due to the attenuated treble, the bass has a warm, soft feel, while its tone is very accurate. The result is an instrumental-sounding bass: whether bass lines or kick drums, they sound like they’re being produced by musicians, completing the rest of the band. Nevertheless, it’s a bass that feels comfortable remaining in the background. It’s not a mean, hard-hitting bass, so it might not be sufficient for the more bass-enthused. This too is a result of its laidback treble, that subdues the clarity of its impact. But even in the background, it’s a bass that remains felt, due to its excellent low-end extension. Its definition and speed are around average.

While the bass is relatively neutral in sub- and mid-bass quantity, the UE18+ Pro’s warmer tone results from an equally linear upper bass. This is a region that often tends to get cut in order to create a cleaner sound, and an airier stage. But in doing so, it removes a layer of richness from the music, such as the lower harmonics that add their own sense of realism and naturalness to the presentation. And equally important, attenuating it affects the warmth of the tone, and the lower end of the vocal region. Reason for the UE18+ Pro to choose differently. Accordingly, the UE18+ Pro doesn’t create an analytically clean stage or the most separated sound, but it does contribute to its natural signature. Overall, it’s a quality, audiophile bass in tone and extension. It might not be the most impactful, but it’s very coherent in the presentation.

The UE18+ Pro’s midrange is slightly forward, with a moderate amount of thickness in its notes. Due to the excellent balance throughout the midrange, instruments have a fair amount of body, and convey a nice sense of power – this midrange rocks. But the first thought that comes to mind is how accurate it sounds, how lifelike. It’s a realistic reproduction of sound, resulting from both its timbre and lower harmonics; the subtle traces following a note, that contribute to an overall sense of realism. But this isn’t a clinical return of how an instrument should sound; it sounds warm, smooth, and inviting – this is a seriously natural-sounding midrange, resulting from an inherent warmth throughout the midrange.

Many iems struggle with the upper midrange tuning. Manufacturers commonly choose to add a lower treble peak in order to boost an iem’s clarity and precision, preceded by an upper midrange dip. But the dip affects the balance in the midrange, both the instrument size and timbre. The UE18+ Pro’s upper midrange instead remains very linear, followed by a lower treble dip. This not only results in a more linear, and accordingly more beautiful upper midrange, but an overall warmer and more accurate timbre. Whether the chord of a guitar, the beat of a drum, or the sensual note of a saxophone – the tone is just right. Not overly bold, impressive, or sparkly – just a close approximation of how it should sound. At the same time, electric guitars are allowed to screech a bit, but they might miss some bite when moving up the scale. Similarly, there’s only a modest touch of sparkle on an acoustic guitar – a tuning intended on keeping it safe. It’s the result of a tuning that starts to dip after 4 KHz, effectively avoiding the whole sensitive 5-7 KHz area. Because above anything else, the UE18+ Pro’s midrange is smooth.

The UE18+ Pro’s vocals are a highlight; not only within this tuning, but in this shootout. They’re slightly forward, and nicely sized. But most of all, the UE18+ Pro’s vocals are extraordinarily well balanced, resulting from a linear tuning from the upper bass all the way to the upper midrange – the full vocal range. Accordingly, the UE18+ Pro excels in both male and female vocals. And in both cases, the vocal presentation is exceedingly natural. It’s not an overly powerful presentation – it’s just a very realistic reproduction. When you listen to a vocal, there’s little doubt this is exactly how a voice should sound. It’s not just because of the warm tone and smooth sound; it’s like the producer told the vocalist to stand really close to the microphone so they don’t have to stress their voice, while still allowing you to capture the most subtle nuances – the rasp in a voice, or a subtle vibrato. This is the definition of both a natural and realistic vocal reproduction – an outstanding performance.

More than anything, the UE18+ Pro’s natural tone and smooth signature is determined by its treble tuning. Significantly dipping the lower treble results in a simply beautiful treble tone; slightly warm, and oozing in naturalness. It’s the type of treble that makes listening to drums a delight. The attack of a snare drum is a rare treat, but the same can be said of a cymbal. Of course, it won’t be the most sparkly in nature, nor is it particularly upfront in its detail retrieval. And its definition and speed are only average. But it’s the type of treble tuning that actually makes you want to listen to the treble.

But no good deed goes unpunished. Unfortunately, the treble dip comes with its own consequences. The lower treble tuning produces a smooth note release, but sacrifices a bit of its precision in doing so – the articulation of notes, and precision of imaging. In addition, while the UE18+ Pro’s tone excels for band-based instruments as guitars or brass, the attenuated treble affects the tone of string instruments. There’s just a slight wooliness around the note of a violin or piano. This is also partially the result of its main critique; the lower treble dip affects its transparency. As a result, instruments don’t come across as pure as they could, which becomes especially apparent with an instrument like a violin. Even so, it doesn’t necessarily feel as a downside, due to the coherency of the presentation.


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About Author

Nic is currently in pursuit of a PhD degree in social neuropsychology, while trying not to get too distracted by this hobby. In pursuit of theoretical knowledge by day, and audiophile excellence at night. Luckily for him, both activities are not mutually exclusive which helps to lighten the workload. Always on the go, Nic's enthusiasm for hi-fi is focused on all chains of the portable system: iems, cables and daps.


  1. Hi. I am a Korean audiophile. And i using the ‘ue18 + pro’. Your review is very impressive. I read your review and thought the review was perfect. Thank you very much for providing a good review. I have a question. What is the best audio player for ‘ue18 + pro’? And what should be considered in matching? Once again, thank you. Have a nice day.

    • Thanks for the kind words buddy! Personally, I found the best source for the UE18+ the Lotoo Paw Gold perhaps. Due to the 18+’s warmer character, it can feel a bit too warm with warmer sources, which might affect its precision of imaging or transparency. For instance, even though the AK380cu is technically better than the Lotoo Paw Gold, the image was more precise with the Lotoo. However, it strongly depends on preference of course, if you generally prefer a warm and smooth sound, a warmer source might be better (although I did not like the pairing with WM1Z for instance).

      Let me know if you have any more questions.

      • Thank you for your kind answer. Thanks to that, I understood easily. Actually, I like warm and smooth sound. In my memory, WM1Z was my taste. Do you think WM1Z is technically sufficient? I mean … is it the one of the best device? Also, one more question, are there CIEM that are upgraded in every way, sharing warmth like ‘ue18 + pro’? I was satisfied with ‘ue18 + pro’ but just curious. Thank you so much.

        • Yes I can definitely understand how the WM1Z would fit your taste, and there is no question that it is an excellent device. Despite its warm tone, it provides a clean sound with excellent separation and a nice 3D stage. Its exceptional strength for me, is that it makes even brighter iems sound accurate in timbre. However, my personal issue with it is that I found the transparency could be greater when compared to the AK380cu for instance, which used to be my main player. But I had my WM1Z modded a while back by improving the internal wiring, which gave it a more balanced signature for me and better technical performance. Now it is my main player, I like it very much. But to get back to the UE18+, even though the 1Z and UE18+ are both excellent, the pairing didn’t work for me. This is personal of course, but for me the pairing is less good with already warm iems like the 5-Way, UE18+ or Prelude.

          As for something ‘better’; it will come down to preference of course, and note that I am heavily biased in this case, but take a look at the Empire Ears Phantom (and maybe when you can try it at your dealer in Korea?). It offers a natural sound, but has a more airy 3D stage and improved transparency.


    thanks for the epic review.

    Could you please tell me how the UE18 compare to the NT6 Pro?

    and a point to clarify, u said UE18 has a dip in lower treble, but you gave it a higher score than the NT6 Pro, which is known for its quality treble? is this just a reflection of your preference or? I mean a dip from what i understand is same as recessed, which is a bad thing or?

    • Hi buddy, thanks for the kind words. This is the complicated thing about audiophile terminology, attenuated refers to its response in a frequency graph. But this is something different than recessed; recessed just means it is lacking. The treble of UE18+ is not lacking in this sense, by dampening its lower treble frequencies, they simply created a warmer more natural timbre of its treble, as well as a generally more natural signature.

      You’re asking a very good question about the NT6pro’s vs. the UE18+’ treble. But as it happened, I wrote a very detailed post about the interpreting the scores last week on Head-Fi, and I used the NT6-pro as an example. Maybe I will repost that to THL sometime. In the meanwhile, take a look at it and let me know if you have any questions after. TLDR: both are good treble, but the UE18+’ treble has a more accurate timbre.


      • Hi flinkenick,

        thank you so much for the reply, i read through your post in the link, very insightful, a great read! Especially the part about how hifi companies tune towards older and richer consumer segment, blew my mind a little, never thought about that.

        I listen mostly to k-pop and female vocal/ballads, and enjoy some violin/piano too.

        How do you think NT6Pro UE18+ and SE5 ultimate would perform for such genres? would the lower treble dip in ue18 and the softer nature of SE5U’s treble mean less satisfying female vocal and violin?

        btw do does the silicone make u sweat more than acrylic? thats my main concern with SE5.


        • Hi buddy, my guess is the NT6-pro would be the best match for you. The determining factor here is how you like your treble. If you are you a sensitive listener, the UE18+ or 5-Way would be better. But if you like your k-pop, as well as violins and pianos, to sparkle and shine, the NT6-pro is the easy choice.

          In all cases, the vocal presentation would be satisfying. Even though their vocals are slightly different, the NT6-pro, Ult and UE18+ all have really outstanding vocals. The UE18+ and Ult sound warmer though, while the NT6-pro sounds a bit clearer and sweeter perhaps. UE18+ in my opinion has the most realistic and detailed vocals, but the others are also a treat to listen to.

          I live in a cold European country, so my only concern is rain, not humidity. But I will check with others about silicone and get back to you.

            • Nice! Hope they’re to your liking, and let me know if you have any questions after.

              As for the silicone, I asked two others and they said they didn’t have any problems with sweat. But you might want to check with others to be sure if you’re serious about them, maybe people in your own country if possible.

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