Symphonium Audio Helios Review

Symphonium Audio Helios Review

We review the Symphonium Audio Helios which is an aluminum alloy quad BA driver universal IEM using the company’s propriety FLAT technology. It is priced at $1099.

Disclaimer: This unit was purchased by the reviewer and does not have to be returned. Headfonics is an independent website with no affiliate links. You can find out more about Symphonium Audio here. 

You can click here to learn more about the Symphonium Audio gear we have previously covered on our website.

Note, that this article follows our latest scoring guidelines which you can read here.

Symphonium Audio Helios Review
Symphonium Audio Helios Review
The Symphonium Audio Helios was what got me listening to all BA IEMs again. When I’m saying it broke stereotypes for me, I’m not kidding, I had to make sure that there were no dynamic drivers or electrostatic tweeters in this several times.
Slide here to add your score on the gear!37 Votes
Excellent bass and treble response
Impressive dynamics and imaging
Holographic soundstage
Large angular shell that may be hard to fit
Power hungry
Reader's Score

Symphonium Audio is a small Singaporean-based brand with big sound aspirations that you might have heard of in the last five years since launching its first IEM, the Mirage.

Run by just two guys who started as community members, the team has since launched three successful releases; the Helios, the Triton, and the Meteor.

When I was asked to write for Headfonics, I kept coming back to Helios, their first major release, which once again renewed my excitement for where the industry is going since I first got involved with it nearly a year ago. 

Tech Highlights

Retailing at $1099, the Symphonium Helios is a quad-balanced armature driver set of universal in-ear monitors tuned in a four-way crossover.

The Helios also comes with the brand’s exclusive FLAT impedance matching technology developed with Subtonic Audio, which means the source output impedance won’t affect the sound. The Helios shells are machined from AL6061 grade aluminum alloy.

Symphonium Audio Helios Review



The Helios is finished with a sleek matte black color scheme with small logos on the bottom corners. It gives off a very professional and straight-to-the-point vibe. The finish doesn’t scratch or gather fingerprints easily.

Form Factor

The housing of the Helios is quite big with a single bulb extending from the shell. This may be an issue for folks with smaller ears who traditionally have trouble fitting IEMs like this.

For many, the IEMs may stick out of your ear about a half inch to an inch depending on your ear shape and tip size.  In my personal experience, I had no trouble getting the Helios flush with the right tips, but I do have quite wide and shallow ears.

Symphonium Audio Helios Review
Copyright Symphonium Audio 2023

Comfort & Isolation

Isolation with proper tips and deep seal is excellent.  I’ve used the Helios on several flights, and it sometimes isolates better than a few of my custom-fit IEMs.  This is thanks to the sturdiness of the shell and no venting

Due to the size and fit, it is completely normal for the cable ear guides to go to the middle of the ear and not flush in the crevice. In long-term use, I found no discomfort. It is important to tip roll until a proper deep fit is secure


It’s important to note I didn’t have much luck with the included stock tips. To ensure the best experience, I would encourage doing your own tip-rolling.

  • DUNU Smoky S&S Tips – These tips resulted in the most well-rounded presentation of the Helios and the ability to achieve a proper deep seal with the smaller sizes
  • Symbio F – These tips resulted in the most relaxed presentation out of any tips I tried. It’s also my personal preference for comfort and long-term listening sessions
  • Symbio W – The W gives the Helios a slightly more full and engaging presentation. Expect fit to not be as flush as a trade-off
  • Azla Sedna XELASTEC – Sedna tips are for those who want more of a focused treble presentation. XELASTECs do result in the Helios sticking slightly more out of your ears
  • SpinFit CP100 – As a fan of SpinFits, I was quite shocked that this was my least favorite pairing resulting in the presentation of Helios sounding quite hollow and lacking, even with a proper seal
Symphonium Audio Helios Review
Copyright Symphonium Audio 2023

Stock Cable

The Helios comes with a low impedance 26 AWG copper cable built in collaboration with Altalune Audio. It is well-built, light, and doesn’t kink or have any microphonics.

Connections in 2.5 mm, 3.5 mm, and 4.4 mm are available to be selected from. It does everything I would want for a stock cable. The connectors could be sturdier, but that’s the only area I can nitpick about.

A suggestion I have here for Symphonium Audio is to include the option for a cable upgrade, perhaps through another collaboration with a higher-end cable brand such as PLUSSOUND or Effect Audio.

Packaging & Accessories

The Helios comes with a pretty standard selection of tips (two types; the Azla Sedns and Symphonium’s stock tips), the stock cable, and a carry case. 

Azla Sedna Shorts are also included now versus the original launch tips as a result of customer feedback. I do wish more thought was put into the packaging and the case provided given the price point of these IEMs.

Symphonium Audio Helios Review

Sound Impressions

The Helios is something I would best describe as mildly V-shaped with a neutral-to-bright-leaning sound signature that has a lifted emphasis on the sub-bass. It is incredibly coherent and well-balanced with a proper deep seal.


Breaking stereotypes is what the bass on the Helios does. It’s so infectious of a listen!  Thought BA drivers couldn’t pull off great bass? Think again. There’s plenty of rumble and slam here with the Helios more focused on the sub-bass than mid-bass.

It rather fills the mix with wonderful tactility and presence, being tight and deep.  It doesn’t bleed into the mids at all.  It’s not as great as DD-based IEMs such as the Empire Ears Odin and the Sony IER-Z1R but stands above the rest of the all-BA pack.


Lean is the first word that comes to mind from listening to Helios. Both male and female vocals can be quite dry. As a quick nitpick of the Helios, for those of us who like their vocals to be more engaging and romantic this IEM may be not for you. 

I personally would have preferred a bit more heft and fullness in this area, but I can respect the choices made. It’s very clear and works well with the sound signature.


Setting new standards for what listeners should expect out of a kilo-buck IEM is exactly what the Helios does.

Despite leaning bright at first listen, it is tuned excellently and overall, quite smooth. Indeed, the treble is so refined and present that I keep double-checking whether there are actually no ESTs in here.

Staging & Dynamics

The soundstage of the Helios is hard to describe. It’s not overly deep or wide nor is it lacking in those descriptions. It is more holographic and 3D-like but not in the traditional manner. It is more to the back of your head, so to speak.

Dynamics are a highlight of the Helios, more so with micro contrast than macro. Tones are quick and straight to the point, but you don’t miss a beat. For the company’s first flagship release, I couldn’t be more impressed.



The Helios is quite hard to drive compared to most IEMs. Using a cable wired for a balanced connection is highly recommended to get the most out of the experience.

This means the drivability of the Helios is a concern as a decently powered source will be required for use on the go and that might rule out some of the weaker powered dongles in the market. Something with strong dynamics like the balanced-designed Questyle M15 might prove suitable though.

iBasso DX320 Review

Source Pairings

Astell&Kern KANN MAX

The KANN Max has a more relaxed sound that pairs well with users who may find the Helios a tad bright up top. It results in a softer bass presentation as well as a more relaxed treble.

iBasso DX320

My personal favorite pairing resulted in the most engaging sound out of all the products discussed here. The DX320 combined with AMP 11 MK2 ramps up what the Helios excels at, providing a deeper sense of sub-bass rumble and more warmth in the midrange, helping some of the nitpicks I have about the IEM’s lean midrange tuning.

iFi Audio GO blu

The GO blu is an excellent truly portable choice if you’re looking for something that leans warm and stays true to iFi Audio’s house sound despite not using a Burr-Brown DAC.

Add some xBass DSP for a seriously fun time with the Helios and notice people who are staring at your feet while you tap your feet non-stop. A truly worthy pairing for the magic button!


The FiiO BTR7 is another noteworthy truly portable device if you’re looking for a more neutral source owing to the use of an ESS DAC compared to the Cirrus Logic DAC the GO blu above has. 

The BTR7 also has a clunkier UI than the one-button ease of use with the GO blu, but it has a quieter noise floor, more power, a mobile app for further customization, and better build quality.

FatFreq Maestro SE
Copyright FatFreq 2023

Select Comparisons

FatFreq Maestro SE


Seeing as both Symphonium and FatFreq are start-up Singaporean companies that have gained an incredible amount of traction through community respect and support, it seemed only right to compare the $1700 Maestro SE (MSE) to the Helios. 

While the Helios hails from an all-BA configuration, the Maestro SE is a tribrid set utilizing DD, BA, and EST drivers.  I see both as two sides of the same coin, the first being for lovers of bass and the latter being for lovers of treble. I would also encourage those who do not want a dry midrange presence to consider the MSE first.

Both are lacking in similar areas in terms of packaging and presentation but make up for it in terms of sound.

The Maestro SE does have a better stock cable than the Helios, being well-built with better connectors and offering modular terminations but the additional price difference should be taken into consideration.

The Maestro SE like the Helios is quite chunky, and those who struggle with the fit of the Helios may also struggle with the FatFreq design.

Campfire Audio Solstice

Campfire Audio Solstice


Although custom, the Solstice at $1,500 comes to mind as a unique comparison as it’s an offshoot of the already legendary Andromeda but is, in my opinion, improved for my tastes. 

The Solstice maintains the sparkle that made the original legendary with a slightly more neutral overall sound and forward treble presentation utilizing 5 BAs.

Those should choose the Solstice if they’re looking for a better fit but are okay with losing out on the DD-like BA and excellent treble the Helios brings. Some may find the Solstice treble too forward, but it also has a richer vocal presentation that may be right for the listener to consider.

The presentation and build of the Solstice are something to consider when making your next purchase. It is levels above the Helios in build quality as well as its packaging.

What the Helios comes with may come off as quite bland, while the Solstice screams the quality that Campfire Audio is already known for. Nicely done.

FiR Audio VxV


Coming in slightly less expensive than the Helios, the VxV is a highly underrated everyday carry IEM intended for those looking to kick back and relax with.

Despite being a different flavor of neutral as with the Helios, the FiR model leans neutral-warm instead of leaning neutral-bright. It uses a dynamic driver for its lows and 4 BAs to create a sound that has grown positively on me since my first listen.

It may not be as technical or as impressive with its bass as the Helios, but if you’re looking for something less offensive and easygoing no matter what genre of music, the VxV should be added to your consideration list.

Symphonium Audio Helios Review
Copyright Symphonium Audio 2023

Our Verdict

The Symphonium Audio Helios was what got me listening to all BA IEMs again. When I’m saying it broke stereotypes for me, I’m not kidding, I had to make sure that there were no dynamic drivers or electrostatic tweeters in this several times.

No IEM can be perfect, and the Helios shows that in its vocal presentation. However, it makes up for it easily with incredible bass and class-leading treble performances.

Combined with their proven technical ability with this IEM, Symphonium Audio as a brand has been extremely open to the community asking for feedback. With that potent mix, I couldn’t be more excited about what the brand has coming next.

Symphonium Helios Technical Specifications.

  • Driver Crossover – Custom Tuned True 4-Way Crossover with FLAT Technology
  • Frequency Response – 12Hz – 24kHz, ± 2 dB
  • Sensitivity – 104dB/Vrms @ 1 kHz
  • Impedance – 8.5 Ohms @ 1 kHz
  • Socket – Spring Loaded 0.78mm 2-Pin
  • Cable – 26 AWG Pure OCC Copper
  • Cable Impedance – 0.20 Ohms (2.5mm), 0.25 Ohms (3.5mm), 0.28 Ohms (4.4mm) @ 1kHz
  • Limited 1-Year Warranty

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