Symphonium Helios Review

The Helios is a new in-ear monitor product from a relatively new brand out of Singapore called Symphonium. The brand started out in 2017 and have three current products in their line-up. The Helios is their flagship product and comes in at about $1099 USD. 

The Helios features four balanced armature drivers in a configuration that was developed in collaboration with some familiar faces for those of you who have followed Audio Discourse on YouTube -- mainly Leneo, Toranku, and Valoncia, who have started their own brand, Subtonic, and working on exciting new products together. 

So that's a heavy disclaimer here, as I have worked on Audio Discourse's YouTube channel along side some of the folks involved in the creation of this product. This tour unit was loaned out to me from Symphonium directly, and this unit, along with a few others across the world, are being sent to various people in the community for feedback and impressions. All that said, as usual, I try to minimize as much bias as possible and have come into this with excitement, but also will provide my critical takes as well.

The Helios tour unit was sent with two copper-colored balanced cables in 2.5mm and 4.4mm varieties. These two cables are very soft and supple, and I find them both attractive and easy to use. They terminate in 2-pin connectors, and unlike most cables available, these cables do not have pre-shaped hooks. 

The package also comes with a hefty round screw-on metal case that is polished metal and has a nice attractive and luxurious look to it. I am typically not a big fan of these screw-on round cases, but this one is pretty nice and I'd probably use it for storage at home.

The Helios shell design is a rounded triangular shape that isn't too dissimilar from others like 64 Audio and Tachijim's general shape and design. It is however quite large, and has a deep cavity and a longer than average nozzle that is also about 5.75mm in diameter. It is a bit on the large side, and is meant to for a deep insertion into your ear canal. 

This can present some challenges to small-ear hole folks like myself. My left ear was able to get a deeper insertion than my right, as my left ear canal is just slightly larger and has a less sharp bend to it. My right ear is narrow and has an early and sharper bend, and so the nozzle length and diameter hits up against my ear canal a bit prematurely, and so no matter how deep I try to push it in, its maxed out due to the interference.

This causes the IEM to stick out a little further and at a kind of strange angle out of my ear. All that said however, with the right sized tips (in my case, SpinFit CP100 Small), I was able to get a tight seal and no real issues with pain or discomfort. It just didn't look or feel as secure as I hoped it would. I did not have the same types of pain I felt with the Moondrop Blessing 2 or the Campfire Solaris despite them also having similar fitment issues due to nozzle length, width, and angle.

Sound Impressions

The Helios is a very well-tuned IEM that expresses a nice deep sub-bass presentation with clean lower-mids, and a smooth mid-range and treble response that falls in-line with my preferences. It can be perhaps a smidge bright but nothing really to concern about if I had to nitpick its tonal balance. I could also ask for just a little more mid-bass for extra warmth and smoothness, but man, this is a nicely balanced IEM that should be a great all-arounder for most genres.

If I had not known the quantity of the driver count, I may have thought there were more. The 4-BA configuration gets a lot of performance on this IEM, especially when I compare it to my beloved 4-BA Viento B Custom IEM. Yes, that one is several years old now, but it still stands strong in my opinion due to its fantastic tonal balance and coherence.

The Helios takes a similar tonal balance, but adds more sub-bass performance and adds a lot more dynamics to the overall quality. Bass has better texture and punch, and there's a nice amount of sub rumble that can be felt in my ears. It can slam when it wants to, though not as much as some other IEMs I have tried of course. The Monarch and Odin slams just a bit more for similar sounding gear.

Symphonium's mid-range is a perhaps a tad lean in the lower end, but has a nice balance in the upper mids where I don't find it too lean nor too hazy. Some people may find this to be a tad lean overall given the entire mid-range response as whole, but for me personally, I really enjoy this presentation, which is slightly dry, but very clean and clear, and strikes a good equal balance to the spectrum.

Treble, despite being perhaps just slightly more elevated than I like, is very smooth. There is a refined and buttery slickness to it that reminds me of the best EST IEMs (i.e. Odin), or even the all-BA ultra-warm and laidback Vision Ears sets like VE8 and Erlkonig. 

One of the most noticeable sonic impressions I found with the Helios, for good or for bad, is that it sounds like some notes or some frequency range sounds a bit more forward and closer to my ear than others. The midrange just seems a little bit louder than the rest, which is good for those who enjoy hearing the mids, and for some reason, I do feel like I am turning this IEM a little higher up on the dial than others. Still, I do find that I prefer a slightly more relaxed tuning, and at times I do think that the Helios' mids are a bit aggressive. 

The dynamics are very well done. Despite what I say in the last paragraph, there are nice varying levels of sound range here, and quiet moments come off quiet while loud moments are intense. It's not the best IEM in terms of macrodynamics I've heard, but it's definitely above average.

I spent a lot of time with the Helios in all sorts of genres and musical selections -- anything from old classic rock, to jazz, to electropop and folk, to country and to classical. It does well with all genres. I did find it best for some music specifically though.

For example, the subbass gain, tacked on with the nicely tuned upper-midrange is a great combination for the newest Chvrches album, "Screen Violence." The Helios does well with the electropop band's mix of deep subbass synths, and Lauren Mayberry's vocals. Even the dark, emotive track "How Not to Drown" featuring The Cure's Robert Smith sounds fantastic on this IEM.

I also spent a bit of time listening to Massive Attack and Morcheeba, trip hop legends from the past with the Helios, and again felt it works well with this electronic brand of music. Helios provides the much needed deep subbass this genre asks for, while also the electronic synthesized keyboard play on full display.

I will say that my most listened to music of late, trio-based jazz music, is probably the least favorite stuff I have heard on the Helios. Perhaps it's due to the lack of low-end warmth and just not having the real grunt of the double bass stand out, or the slightly forward piano notes being a distraction. This wasn't my favorite combination for the music I played with on the Helios, but again, it is still very enjoyable and well-resolving for this music.

The Kilo-buck Market Competition

The Helios enters competition against a lot of other $1000-ish in-ear monitors that are very popular and very good. Here are just some of the ones I can think of off the top of my head:

  • Campfire Andromeda (2020)
  • Sony IER-M9
  • Hidition Viento
  • Thieaudio Monarch
  • Unique Melody MEST

There are definitely others to consider, but these are some of my top ranked IEMs and are tough, tough competition for a new company with a new kilobuck entry. How does it stack up? 

The Helios' defining difference between most of these IEMs is their sub-bass elevation and focus with the exception of the Thieaudio Monarch, which have very, very similar tonality. The Helios is more coherent, with better clarity and resolution from my memory versus the Monarch, and the treble is smoother. It's also a little more costly at $350 more.

The Andromeda is quite a bit different sounding, while also sharing an all-BA setup. Both have good dynamics and resolution, while the tuning is where they go off on different tangents. The Andromeda is warmer with a significant amount more lower mids and midbass compared to the Helios.

The IER-M9 is also an all-BA setup, and just has a much different sound. It's ultra smooth and warmly tuned and darker. Its a more relaxing listen and does not have a sub-bass focus. It's been a while since I really listened to the M9, but I never felt the technical performance as compelling on first glance as I did with the Helios. It's not saying that much, but perhaps it the smoother, warmer nature of the M9 not showcasing its full talents.

Finally, the two IEMs I do own: The MEST and the Viento...

The Viento is also a 4-BA setup, but I feel its tonally better than the Helios with similar upper mids and treble, but less subbass and more mid-bass warmth. It gives a more even sound throughout, while the Helios has probably a bit better clarity, texture, and excitement.

The MEST is quadbrid, that also has a subbass focus, but not nearly as energetic as the Helios. It also differs in the uppermids, where the MEST is quite a bit more relax and darker, given the comparison between the two very different flavors.

Podcast Impressions

This was a live stream video of first impressions of the Helios from myself (Antdroid) and Rush on our Youtube channel:


The Symphonium Helios is a really nice entry to the market. I am quite impressed by its technical ability and it has a tonal balance that I think will make it a favorite amongst many, especially those who enjoy electronic and other sub-bass focused music. It has a lot of the tangibles in place to really set itself as the top "neutral with sub-bass" top dog in a crowded marketplace. While I still prefer my Viento-B, another "neutral with sub-bass" IEM just a little bit more for its tonal balance and warmth, I can see the Helios being a close runner-up, but with better technicalities.

The biggest gripe I really have with the Helios is the shell design. It's large, requires deep insertion, and I'd prefer a lighter acrylic shell over the metal housing it comes in, but for many, this might not be a big deal. 

The Helios is good and a solid-buy. I look forward to the next Symphonium and Subtonic collaboration as I hear there's something(s) even bigger down the road in the high-end market that gets me very excited. This is a teaser, and a really good one at that.

Audio Discourse Interview with the Creators

Finally, to wrap everything up, here's an interview with Subtonic hosted from Rush of Audio Discourse's YouTube channel.

View the product ratings on Antdroid's IEM Ranking List and/or Antdroid's Headphone Ranking List


  1. Great review!!
    I'm currently stuck between the helios, viento, MEST MK2, and Monarch MK2 for acoustic/bands/vocals. Which IEM out of those four do you think have the best resolution/imaging/3D?
    Keep up the great work!


Post a Comment