Fit and Comfort

Seen above is the right channel of the ThieAudio Elixir placed into an artificial ear mold with the included size M silicone ear tip installed. I have average-sized ears, and the ear mold above represents my own experiences well enough as a proxy. Size M silicone tips are my go-to for testing since foam tips are not included by some. As we only have one of each type to try, I I am showing a photo of the fully assembled ThieAudio Elixir as used for listening and testing. The shell curvature has several points of contact in the ear concha; however, the short, stubby nozzle that is also heading on into the ear canal is a deterrent for a good a fit and seal and why I believe ThieAudio missed out by not including more ear tips—options to get a good fit are few with the stock ones. On the plus side, the Elixir is not very thick and fits into the concha well without jutting out much, and the average ~7 g per side prevent physical fatigue. The pre-formed ear hooks can be hit-or-miss, and an angled housing for the 2-pin connectors would have come in handy as support to the IEMs is in some cases inadequate.

Audio Performance

Audio Hardware

ThieAudio talks a lot about the driver, acoustic chamber, and tuning of the Elixir, but fails to illustrate these points as there are no images, renders, or wireframe illustrations of any of these. I also tried and failed to get more clarity on this matter, especially since the product page sure makes it seem a truly innovative dynamic driver with a totally new type of diaphragm. Instead of the classic mylar, aluminium, or LCP with coatings for stiffness, ThieAudio is claiming interweaved sheets of multi-walled carbon nanotubes to be the diaphragm. While it would have the potential to be extremely stiff and responsive, it's not magnetic enough to move back and forth with the flux generated by the so-called stronger pole magnets. There is then the Beryllium coating on the CNTs which add stiffness while being light, but that does not solve the basic issues, either. I suspect we are again seeing another case of the Be/CNT ensemble as another coating itself, or perhaps associated with something else for movement. One change is the voice coil being a pure copper composition rather than the usual aluminium or copper-clad aluminium wire. Ultimately, I still can't tell you the size of the dynamic driver and make-up of the diaphragm, but ThieAudio's "3-Dimensional Velocity Transducer" marketing talk has satisfied many who couldn't care less anyway.

Where it hurts is the lack of transparency and attention to detail while still claiming these driver components "relay a texture within the sound that is completely unique in typical in-ear headphones, which can only be described as vintage and analog." Well, okay then! At least we get a factory frequency response curve, which we will judge the review sample against. Also, ThieAudio does not provide basic specifictions—impedance and sensitivity—on the product page as this is written. I have asked them to clarify this, but it's a rookie move throughout when a strong platform is laid out to showcase and boast about internally developed new driver tech! Oh well, I can at least tell you these are quite easy to drive—the Elixir is easily handled by even a basic USB Type-C dongle. Going with a portable Bluetooth DAC/amp similar to those we have covered before helps make this a wireless solution while providing more features. The lack of a 3.5 mm audio jack for most phones these days is another reason to consider a DAC/amp or even DAP for portable use. If not on the go, space is less of an issue, but the relatively short cable might still be a potential handicap if using a PC as the audio source.

Frequency Measurement and Listening

I will mention that I have a general preference for a warm-neutral signature with a slightly elevated bass, smooth treble range, detailed mids, and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music.


Our reproducible testing methodology begins with a calibrated IEC711 audio coupler/artificial ear IEMs can feed into enough for decent isolation. The audio coupler feeds into a USB sound card, which in turn goes to a laptop that has ARTA and REW running and the earphones connected to the laptop through the sound card. I begin with an impulse measurement to test for signal fidelity, calibrate the sound card and channel output, account for floor noise, and finally test the frequency response of each channel separately. Octave smoothing is at the 1/12th setting, which nets a good balance of detail and noise not being identified as useful data. Also, the default tuning was used for testing, and no app-based settings were chosen unless specifically mentioned. Each sample of interest is tested thrice with separate mounts to account for any fit issues, and an average is taken of the three individual measurements for statistical accuracy. For IEMs, I am also using the appropriate ear mold fitted to the audio coupler for a separate test to compare how the IEMs fare when installed in a pinna geometry instead of just the audio coupler. The raw data is then exported from REW and plotted in OriginPro for easier comparison.


The IEC711 is such that you can't really compare these results with most other test setups, especially those using a head and torso simulator (HATS). The raw dB numbers are also quite contingent on the set volume, gain levels, and sensitivity of the system. What is more useful information is how the left and right channels work across the rated frequency response in the ThieAudio Elixir. The left channel was separately tested from the right one, and colored differently for contrast. I did my best to ensure an identical fit for both inside the IEC711 orifice, so note how the two channels are practically identical across the entire useful 20 Hz to 20 kHz range! This is a randomly picked retail unit sent from the Linsoul warehouse, so I am very happy with what I saw and heard here. Measurements taken after 25 hours of testing, which included these playing a mix of various songs as well as white or pink noise and sine sweeps, showed no difference. There was no perceived burn-in effect thus, and none was measurable, either. The response with the anthropomorphic pinna in place matched the ideal scenario in the coupler almost perfectly too, with a deviation only past the coupler resonance that has to be taken with a grain of salt, which is an indicator of how good the seal was when installed in the artificial pinna.


Here is the average frequency response for both channels of the ThieAudio Elixir plotted against my personal target taken from VSG.squig.link, which also gives you an idea of my personal preferences to better correlate any possible biases. The tuning of a set of headphones or earphones does not have to match my target as long as it is tuned with some direction, makes sense, and is executed well. After all, no one set will appeal to everyone, and having different options is what makes this hobby so interesting and hard to quantify. In addition to the best fit measurement, I show a shallower fit as fit and isolation of the Elixir may vary in your ears. This has the coupler resonance at 8 kHz, and matches the ThieAudio factory curve very well, although my personal experiences are somewhere between the two.

ThieAudio talks a lot about the tuning and sound signature of the Elixir on the product page, but many of the used terms are vague at best. The aforementioned factory response curve is what to primarily compare my findings to, and in that regard the Elixir is a win already. ThieAudio has an excellent audio engineering team, and the Elixir is a great showcase of it with tuning that should appeal to most people and technical performance to back it. The bass response in particular is class-leading, at least assuming you have a good fit. With ~8 dB elevation from the mids that is mostly maintained in the sub-bass, this set plays well with drums and bass guitars courtesy a large dynamic range for subtle intermingling tones while catering to transient spikes. This makes the Elixir a strong contender for electronic music too, and it makes you feel the bass when it finally drops.

The fit once again plays a role in how the bass transitions into the mids and whether vocals will be forward-facing. Overall, it's a pleasing set for rock music, and male vocals display good separation compared to instruments. Even there was I able to discern different instrument classes well as imaging is good throughout most of the front and sides, with a slight haze around 45° in each direction on the front. Soundstage is fine, but not what you want to get this set for, with a decent sense of space neither compact nor spacious. Female vocals can come off slightly shallow or nasal-sounding depending on who you listen to, and the latter is more likely because of the fairly generous pinna gain. I found it pleasing enough for jazz music, and it also compensates for the otherwise softer treble response.

The higher frequencies are where I did remember this is not a flagship set, with instrument fundamentals and second and third-order harmonics not playing as well with each other. It also is not the most resolving set in the treble frequencies for the price range, but this is perhaps where ThieAudio's relative inexperience with full-range dynamic drivers plays a role. Perhaps it is also a safe tuning for those who simply care more about the bass and mids, but be warned that a good seal may induce sharp ear canal resonances that worsen with a supposed sense of air playing against treble-sensitive listeners. So while the Elixir still has a mostly soft treble, it does test boundaries here and there to where I don't feel comfortable recommending it for naught but instrumental, classical, or orchestral music despite timbre feeling as natural as can be, including on string instruments.

Comparisons

These days, there are so many excellent single dynamic driver IEMs in the price range of the ThieAudio Elixir! I of course had to compare it to my personal favorite thus far, the MOONDROP KATO, which is bested by the Elixir in the bass, it being more technically proficient and even more dynamic—the slightly louder bass response plays a role here no doubt. I'd still pick the KATO for the smoother, more controlled treble response, which caters to my specific preferences, but the Elixir will win over more people here. The others tested so far, including the recently reviewed HiBy Lasya, unfortunately don't stack up as well as the Elixir/KATO duo overall and are only going to appeal to those who want the aesthetics and accessories. But notice how it's all becoming very similar when it comes to the tuning, which may in the future have more companies tune IEMs based on reviewer preferences to where we might not have many options for other preferences!


Pitting the ThieAudio Elixir against the recently released planar IEMs in the same price range, my point of a very formulaic tuning remains; it becomes a case of HRTF preferences more than anything else. These larger 14.x mm full-range planar IEMs are not going to stop anytime soon, having started with the impressive 7Hz Timeless, which competes very well against the Elixir in especially the bass response, but has an even more divisive treble tuning, is prone to QC issues and silent revisions, and harder to fit well. I'll take the Elixir for the money, and the subjectively better aesthetic has its role in that decision. The Raptgo Hook-X is technically a hybrid set, but the planar driver is responsible for the tuning, and the PZT adds extra sparkle through the mids and highs. It is even tougher competition than the Timeless since the tuning is similar, but the soundstage wider and treble response better-executed, but the bass response is not as dynamic owing to the open-back nature of the HOOK-X, so it's more complementary than a replacement to this closed-back set. The two sound very different in practice, so I would say pick the Elixir for bass and vocals and Hook-X for instruments. The TinHiFi P1 Max—review coming soon—and LETSHUOER S12 are less expensive than the others, but present valid alternatives courtesy an easier, more reproducible fit while being slightly less technical. I don't think either does enough to upstage the Elixir even with the price savings, though. Several hybrid sets exist in the price range, but not many that I have tested come to mind as contenders. Perhaps the IKKO OH10 that now costs less and is a bassy set if you prefer a more V-shaped tuning.