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Stealth Sonics IEM impressions thread

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  1. Jackpot77
    This thread is for impressions and reviews of the Stealthsonics U-series and C-series IEMs.

    Impressions links:

    Full review links:


    [More to be added]

    The models:
    7B990113-75E5-4461-8562-C04E863E9D6B.jpeg 03EA1B6F-2DA5-4497-B4CE-2AD17977A267.jpeg 145E0972-EE93-4307-8B02-482DA7995308.jpeg

    The specs:

    The Technology:
    Iso-Stealth Technology: Audiology in Action
    Through our advanced audiology research, testing and international network of over 700 audiology partners, we’re able to go beyond our competitors to engineer ultra-precise, second-bend ear canal impressions to position our IEM within just millimeters of the eardrum. Wearers can listen at safer SPLs for a cleaner mix, with less ear-cavity interference and a consistent sonic experience every time.

    SonicFlo Acoustics: The Aerospace Advantage
    We’ve harnessed our technology breakthroughs in the aerospace industry to optimize aerodynamics, aeroacoustics and airflow performance. We’ve also taken advantage of our extensive research in fluid dynamics principles to engineer our in-ear monitors for optimum sound isolation in any environment.

    Acoustic Optimization: From Drivers to Damping
    Acoustic refinements include extra-large bores that preserve airflow and sonic fidelity and advanced
    venting features to manage resonance. All of our universal in-ear monitors offer Stealth Damping technology
    , featuring a faceplate that can be removed to extend bass response for deep, rich low end that you can feel.

    Space-Age Materials: Comfort and Confidence
    Components are built inside an ultra-light enclosure housed in proprietary composite material that ensures
    a snug, comfortable, slip-free fit, even during long-term use.

    Klarity Valve, Hearing Protection (custom only?)
    The Klarity Valve is designed to release pressure build up in the ears arising from long use of IEMs.
    Without such a 1 way valve, the listener becomes exposed to pressure build up in the ears causing fatigue and hearing stress .

    Ultra Hard Impact Shells Breakage Resistant
    Designed to withstand pressures arising for accidentally dropping the IEMs and other typical accidents,
    the shells are coated with a proprietary lacquer that makes the shells extra hard.
    Last edited: Jun 16, 2019
  2. Layman1
    Last edited: Jun 13, 2019
    Skywatcher and davidmolliere like this.
  3. Layman1
  4. Layman1
    Just a bit of a suggestion/feedback for those on the review tour for these IEMs:
    In retrospect, I would have listened to the U9 first, then the U2, and finally the U4.
    It's a bit like wine tasting, where you save the heavyweights for last.
    After the U4, I thought the U9 had little bass.
    Turns out I was completely wrong, but it took me a while to adjust :)
    davidmolliere likes this.
  5. Richsvt
    These look like some amazing pieces. I like the description of U2...may need to take a closer look. Great, another IEM to purchase....
    Layman1 likes this.
  6. Layman1
    Haha, it just never stops, does it? :D
    Richsvt likes this.
  7. Jackpot77
    They are an interesting collection of IEMs - three distinct flavours. Definitely worth a listen if you can track them down in your neck of the woods.
    davidmolliere and Richsvt like this.
  8. davidmolliere
    So... thanks to @Jackpot77 I am part of the StealthSonics tour and just received the U9, U4 and U2 :)

    I purposefully avoided reading the reviews so far to keep a fresh mind.

    I just had a couple of hours with the U9, fitted with custom art silicon custom tips and I must say first contact is very good. I need to dig more but more often than not first impressions are usually very interesting and don't land far from the final ones (that is, when you exclude, burn in which is done in my case by the first tour reviewers, tip rolling which are covered here with custom tips, and source rolling).

    Image d’iOS (2).jpg

    So first U9 impressions... a few words come to mind : soundstage, textured bass with good extension, balanced and smooth presentation, extended treble. Everything is cohesive and no faults stands out (no harshness, no sibilance, no part of the frequency range is prominent).

    The U9 definitely qualifies as TOTL contender with great clarity and transparency. From memory, there is something reminiscent of the U18t only a tad more warmth and fullness which is a good thing in my book.

    I need to spend some time with it given its performance level there is a lot to process, but I like it a lot.
    Last edited: Jun 28, 2019
    Wyville and Layman1 like this.
  9. SQ13
    I heard the U9 and agreed with the comments: transparent, balanced, good extension, especially the treble. I made the mistake of listening to U4 first which has more prominent mid and bass.
    I was using DX200 amp1 on SE as the 2.5 or 4.4 cable is not available.
  10. Layman1
    Apparently they are working on bringing out more cable options, so watch this space (or their website etc) for more details hopefully :)
  11. Jackpot77
    Believe they are working on collaborations with one or two cable manufacturers for the "Audiophile" side of the market. They are quite like JH Audio in that the touring musician market is one of their main targets, where balanced cables are less of a requirement, hence not launching with them on day one (I believe).
    davidmolliere likes this.
  12. davidmolliere
    So... I have spent more time with the U9 but more importantly I have given a couple of hours to both the U4 and U2 and I must say, this is quite an interesting line up :)

    The U9 really impresses with the detail retrieval, a very accurate presentation with a high level of clarity and transparency as well as impressive soundstage. We’ll see both with the neutral AMP1 II and AMP9 but I suspect this one will match incredibly well (for my taste) with a warmer source like the Korg NuTubes powered AMP9 I should be getting early this week along with DX220. The U9 is tuned almost for monitoring from what I hear.

    Listening to the U4, you wouldn’t think it’s the only one in the lineup that doesn’t feature a dynamic driver, the bass is really well textured for a balanced armature. The fact that the mid bass is more prominent is probably part of the equation as well. I hear the U4 as fuller sounding than the U9, thanks to its lower mids it gains quite a bit of body compared to the U9. It does not feature the same level of separation and resolution as the U9 but it still features a very good level of detail retrieval and a very nice soundstage. Interestingly it provides more excitement in the lower treble department than the U9 which is more focused on the upper treble region. Overall, I’d say the U4 is tuned for fun.

    Last but not least the U2 is very cohesive, with beautiful textures and I probably like their mids the best of all 3, more of a personal taste issue than anything. It’s the most romantic one, and I’ll make sure to include a comparison to the FIBAE Black in my review. I didn’t find the U2 to have more bass than the U4, it rather has a different tuning with a softer attack, bass quantity might be close but I perceive it as more prominent with the U4 thanks to a franker attack. Interestingly the U2 does not lack in the treble department, while it’s more « romantically tuned » (if that means anything :p) it’s still a StealhSonics and detail retrieval is very good.

    I’ll sure have a great two weeks with those 3 :D
  13. davidcotton
    Don't know if you'll be interested in purchasing one if or when funds allow, but it seems they accept stl scans as well for impressions if that helps ? :)
  14. davidmolliere
    I know and it sure has crossed my mind :D
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