Symphonium Crimson: The Heir Apparent

With the Crimson, Symphonium is seemingly counting on a sonic midpoint between their two best performing products being compelling enough to justify placing it in the flagship seat of their catalog. Does Crimson live up to the expectations placed upon it by being the next in Symphonium’s already stellar lineup?

Symphonium Crimson: The Heir Apparent


My interest in Symphonium is largely due to them being one of the most consistent IEM manufacturers today. Pretty much all of their recent products have been met with praise, and have become fixtures of the price brackets they occupy. Their products have even made me question my own preferences and ideas about what an IEM ought to be.

I’m almost never a fan of “bright” IEMs. However, the Helios immediately shocked me with its extraction of reverb tails, vivacious and airy treble, and near-unparalleled dynamics. As a kilobuck contender, it still sits head-and-shoulders above any of its competition for technical performance alone, though unfortunately I’ve found its lean tonality loses its novelty over time and reveals itself to be thin enough to not quite be “all-rounder” material.

The Meteor takes a completely different approach, opting for something much more warm, relaxed, and easy to listen to. It is easily my favorite IEM in the “mid-fi” price tier due to its non-fatiguing tonality, even if it’s not really a top contender at its price in any technical category (and has too much bass for my preference). 

With the Crimson—their new flagship—Symphonium is seemingly counting on a sonic midpoint between their two best performing products being compelling enough to justify placing it in the flagship seat of their lineup. Does Crimson live up to the expectations placed upon it by being the next in Symphonium’s already stellar lineup? Let’s talk about it.

What we like

  • Some of the best bass you’ll find at this price point
  • Well balanced between tuning and technical performance
  • Noticeably immersive soundstage/imaging

What we don’t like

  • Treble above 5 kHz may bother some listeners
  • Midrange could use a smidge more warmth
  • Not the last word in dynamics at this price point
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    Frequency Response/Tonality

    Below is the Symphonium Crimson, measured on the Brüel & Kjaer Type 5128-B HATS, and calibrated to the 4620 + Human HRTF baseline. The boundaries behind the measurement indicate the gradient of preference outlined by the existing speaker and headphone literature. If an area of the response sits outside these bounds, it’s possible that the average listener may find the tone unpalatable.


    We see that the bass sits rather nicely in the upper bounds of preference, as for example the Harman 2018 target does. It has no issues with extension, and the amplitude and contour of the shelf is almost exactly where people tend to like it.

    And in listening, indeed this is probably my favorite part of Crimson’s tonality. It’s certainly richer and fuller than the bass shelf of Helios, while also not nearly as overbearing or as potentially stuffy as the shelf of Meteor.

    Crimson’s bass occupies what is essentially a perfect midpoint between the two, combining Meteor’s expansive and enveloping warmth and size, with Helios’ trademark tactility, speed, and bounce. While I’d say Helios gets the edge in texture in the bass, it does so while having a much leaner and less inviting presentation overall. And while Meteor does win in terms of raw quantity, I always felt Meteor had a bit too much bass for its own good anyway.

    Crimson’s bass is big, rich, lumbering, but somehow never slow.

    I noted early on that the bass of Crimson actually sounded rather similar to the bass shelf of Harman 2018 (for over-ear headphones) but transposed to an IEM. It’s almost eerily normal sounding in that it works with basically any music I throw at it with no complaints. I assume the bass here will be a highlight for most people for this reason.


    The midrange offers the first potential speed bump for IEM listeners, as it’s perhaps slightly thin overall. The tilt between lower and upper midrange is just a bit too counter-clockwise tilted for me, being rather close to the un-tilted Diffuse Field target (which on the above graph would be represented by a flat line) until about 3kHz.

    However, it must be said: Most IEMs are significantly thinner and "colder" here. As such most IEMs are much worse offenders than Crimson in this region, especially since it opts to undershoot around 3-4kHz, which helps bring the midrange to a more headphone-like tilt overall. Crimson is just warmed-up enough to not sound sucked out, and it offers competent support to the fundamentals of vocals and snare drums even if it’s not quite as warm as I personally prefer.

    Even with that preference, I think it’s likely that a more warm-tilted midrange paired with Crimson’s large bass shelf could make things too cloudy. How this area is tuned has a lot to do with how we hear the main relationship between fundamental frequencies and overtones in a piece of music, and it’s arguably the hardest area of the tonality to get to cohere with an IEM’s bass and treble.

    Even if Crimson’s midrange is a smidge lean for my taste, it works very well with Symphonium’s bass tuning choices here, and still gets a solid passing grade from me given it rarely presents issues to me and still beats many IEMs in its class for this aspect.


    I’ve said in basically every one of my prior reviews that the Treble section is where IEMs and headphones go to die… and unfortunately Crimson doesn’t escape this.

    I want to be clear that the above 5128 measurement of the Crimson was taken after almost 3 weeks of having Crimson at home for testing, so the following impressions are not at all influenced by the measurement. 

    Upon receiving Crimson and listening to my reference tracks, I immediately knew I had a big problem. 

    For what it’s worth, I could see much of Crimson’s treble being fine for most listeners. It has a slight flare in a similar spot to the Thieaudio Monarch Mk2 (5-7kHz), but curtails the boost just enough to stop the overall presentation from being a dry, grainy mess like I hear Monarch Mk2 to be. This elevation wasn’t immediately noticeable to me, as it was actually masked by the main issue here: a large 12kHz peak that no amount of tip rolling (and I did a lot of tip rolling) was able to make tolerable for me.

    Now, to be clear, I already know a few people for whom this elevation isn’t an issue. Treble is very user-specific, having a wide range of anatomical as well as preferential variance. Plenty of people will likely hear this peak and appreciate the sense of “detail” it brings to smaller cues like vocal intricacies, minor percussion changes, and reverb tails—the latter of which is something even I can say I like about it at times.

    But for me, it’s more distracting than anything else. Vocal sibilance and breath are impossible to ignore, and it borders on painful at times. Cymbals are splashy and ringy, being pushed much more forward and closer to my eyes than is comfortable. Snare drums at times even sound like they only use a bottom mic instead of blending between the “chains” on bottom head and the stick attack & shell resonance of the top head. 

    Unfortunately, very few things I listened to seemed to escape the uncomfortable sizzle from Crimson’s 12kHz peak, and so this ends up being yet another case where a flagship IEM takes a risk by boosting its treble tuning—ostensibly to increase perceived technical performance—that falls completely flat for me. While again, to others this still may not only be palatable, but preferred, I still have to dock major points from Crimson for this choice.

    Technical Performance

    This is where Symphonium’s previous flagship Helios had gone above and beyond its price tag in the past, so I won’t lie: my expectations for Crimson’s technical performance were very high.

    I’d say in terms of dynamics, Crimson and Helios are on roughly equal ground, though they present rather differently. Crimson is more like a closed back headphone, where its dynamics manifest mostly in how hard the mid-bass of kick drums can hit you. Helios, by comparison, is more about portraying pure contrast between all elements and areas of the music, and thus its dynamics are a little more universal instead of just being relegated to the bass.

    Crimson being a warmer tune than something like the Helios means—to my ear—Helios is still an overall more detailed, texture-oriented, and “fast” IEM. Helios has a lean, unencumbered midrange that brings texture and transient attack forward at any cost.

    However, it’s pretty widely agreed that the "cost" in this case is timbral naturalness, as basically everyone has agreed that Helios is a pretty thin sounding IEM.

    Crimson decisively takes a step forward in the realm of timbre, and wrangles back some tonal versatility and warmth that Helios clearly lacks. Unfortunately, in doing so it has to take one step back in technical performance, and sacrifice some of Helios’ nimble celerity for what is ultimately a significantly more well-rounded and listenable presentation.

    That being said, the delta between the two in resolution and dynamics certainly isn’t massive by any means, but I do think it’s likely many people may notice that Crimson is a little less “tech-forward” than Helios.

    Luckily, there’s still at least one thing Crimson does better than Helios and Meteor, and it’s actually the thing I’d say Symphonium’s IEMs have unilaterally done well up to this point: soundstage.

    I really, really don’t care about soundstage in IEMs and headphones. I regard it as an illusory perception borne of tonal coloration (among other things) that is rarely going to be experienced the same way between listeners.

    But it’s hard not to give credit where credit is due: Crimson is probably one of the most spacious and enveloping IEMs I’ve heard. It actually mixes my favorite parts of Helios and Meteor’s technical performance in this regard, combining Meteor’s effortlessness in layering and size with Helios’s eerily discernable reverb trails.

    I’d say even if Crimson mostly plays on the overall level of technical performance of the Helios, the presentation it goes for is more akin to the Meteor. It prioritizes being expansive and fun, with large but well-layered sonic images.


    Cards on the table: purely as a function of personal taste, Crimson is unfortunately my least favorite of Symphonium’s current IEM lineup. 

    Meteor is still my favorite, as the warm midrange, relaxed treble, smaller shell, and appealing price still makes it one of my favorite IEMs on the market. Helios is still the most technical overall, and for that reason it has a place in my heart above most other kilobuck IEMs that simply don’t come close in terms of dynamics and texture.

    While yes, Crimson is tuned better than Helios, it loses some of the technical “X factor” that makes me adore Helios in spite of its tonal flaws. And while yes, Crimson is more technical than Meteor, it’s not tuned as well as Meteor for my taste. So I’m left feeling like Crimson, as a set of compromises chosen to maximize the best parts of its predecessors, just wasn’t made for someone like me.

    But I think this all depends on perspective, and really comes down to what the listener indexes for. In fact, if you’re interested in a different perspective, check out Resolve’s review of the Crimson on our YouTube channel.

    Instead of the framing I just gave, I could very well see someone saying that Crimson—both tonally and technically—occupies a rather comfy spot between Helios and Meteor. It’s almost certain that a lot of people are going to find Crimson much more compelling than I do for this reason.

    After all, audio is a market of compromises. If we’re going based on well-roundedness, there’s a solid argument to be made that Crimson is the most well-rounded offering that Symphonium has yet released.

    For me though, I can’t help but feel like Symphonium was so close to nailing this, but just took a risk with that 12kHz elevation that—to put it generously—didn’t pay off for me. 

    If you want a more technically-proficient take on the Meteor and are willing to try a more aggressive tuning, or want a more relaxed and palatable take on the Helios and are willing to sacrifice a smidge of raw technical performance, Crimson rather indisputably hits these marks.

    As such, I think it deserves its place in the flagship seat as it most completely embodies the values and philosophy that’s underpinned Symphonium’s products so far.

    But if you—like me—are more treble sensitive or want a warmer, darker, thicker option, I think the Nightjar Singularity might end up being a better pick for that set of needs.

    Thanks so much for reading. If you have any questions about this article, feel free to start a discussion on our forum below or ping me in our Discord channel, which is where you can find me and a bunch of other headphone and IEM enthusiasts hanging out. Until next time!

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