Fit and Comfort

Seen above is the right channel of the Craft Ears Omnium placed into an artificial ear mold with the included size M single bore 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 brands, and I found these tips to work plenty fine in terms of achieving a consistent seal as well as measuring how I hear the IEMs too. The double flange tips can possibly help with a more secure fit for some, but I felt it was a touch too smooth and the IEMs were coming out more easily from my ear canals. Those tips also resulted in a blunter bass, so I was happy the single bore ones worked nice enough. The ear tips are less of a concern than the nozzle itself though, and for once it's not the nozzle length or diameter—although 6.35 mm is still something to be aware of if you have smaller ears/ear canals. No, it's the part where the nozzle has a steep insertion angle, nearly 45° from the shell surface, and I know multiple people who have struggled to fit these in the ears. Comfort can be an issue thus, assuming a seal is achieved in the first place, and Craft Ears says this was necessary to achieve the sound signature of the Omnium. I count myself lucky that the Omnium fits fine, and I'd say ~75% of attendees at a show this was at recently found themselves having minimal fit issues too. The shells themselves are relatively slim depth-wise and average in the other two dimensions, so a deep fit with the nozzle can make the Omnium fairly flush fitted in the ears with plenty of support. Add to this the hidden vents preventing pressure build-up and the cable coming out at an angle already such that the pre-formed ear hooks naturally fit over and behind the ears, and I was personally quite happy with the overall fit and comfort achieved. The cable chin slider also works as expected so it can provide more support and help ensure the IEMs remain firmly in place even if you end up moving around.

Audio Performance

Audio Hardware

The Omnium is a tribrid driver set of IEMs in that it uses three different driver types. The bass is handled by a 9.2 mm dynamic driver using a liquid silicone rubber (LSR) diaphragm before giving way to a 10 mm planar magnetic driver dedicated solely to the mids, making for a novel implementation already. The mids-to-high transition is catered to by a single balanced armature driver, before two other BA drivers come in for the highs and two more BA tweeters cover the ultra-highs. This makes for a 1+1+1+2+2 split, albeit Craft Ears says the Omnium uses a 6-way crossover so one of the two BA driver sets is further split up. Regardless, a true 6-way crossover is exceptionally complicated and expensive, something not usually seen in IEMs even in the price range the Omnium belongs to. The Omnium also features some Craft Ear tech, including True Load (flat impedance curve) allowing for the tuning to remain consistent across sources, and SES 3.0 (Space Expanse System) that aims to provide a wide soundstage. This is in addition to a tubeless design with "custom-tuned acoustic chambers and resonators, as well as special waveguides to optimize sound delivery," in their own words. The end result is a set of IEMs that is slightly more current-demanding than voltage based on my testing, with a rated impedance of 12 Ω and an unspecified sensitivity that I suspect is on the lower side of average. It's fine with a decent portable DAC/amp though, but does scale with more powerful sources still in the transportable realm.

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 that 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 a capable and transparent DAC/amp—I used the Questyle M15 here. 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 Craft Ears Omnium. 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! Keep in mind that resonance peak matching at 8 kHz can introduce some measurement artifacts, but even then the two channels were so close. Craft Ears says that's the least they can do for customers willing to pay premium prices, with everything undergoing multiple stages of testing and quality control. Needless to say, I certainly didn't notice any channel imbalance in the ears. This is also a randomly chosen retail unit that was available in stock, as opposed to something cherry-picked for review, so I am quite hopeful that paying customers will find similar satisfaction. Measurements taken after 75 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 well enough, and this is more an indicator of how well and how deep the IEMs can fit in a human-shaped ear, or at least one that doesn't complain about discomfort.



Here is the average frequency response for both channels of the Craft Ears Omnium 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. This is in addition to a second graph using a newer target that's based on a more scientific methodology involving a -10 dB tilt (-1 dB/octave) applied to the diffuse field target for the newer, more reliable B&K 5128 but then compensated for my exact 711 coupler instead. Do scroll down to the targets in my database linked above and see the new 5128 section to the left where you can click on the yellow question mark for a brief primer. The bottom line is this target is closer to what many people are likely to prefer out of IEMs and headphones alike. I have chosen to plot this graph with the frequency response normalized/compensated to the target to make it easier to see how the Omnium is tuned—basically unlike anything else I have heard so far.

That is a massive statement to make given the hundreds of IEMs that come out each year, with the vast majority sounding very similar. Indeed, there are quite a few which try to conform to the Harman in-ear target, and many others that go for a neutral w/bass boost tuning too. The Omnium is special in a few different ways, and the end result is truly unique sound which makes it stand out and be highly memorable, regardless of whether this is the sound for you. There's so much sub-bass here, a bit too much for me personally, which makes the Omnium feel like a nightclub in the ears. I remember my first time listening to the Omnium and just not wanting to take it out because it was just so much fun. Michael Jackson's Billy Jean popped up randomly in my tracklist, and the hi-hat beats hit so hard here. But then I kept listening and realized it was primarily the first beat, and then there wasn't much followed up with the trailing ends of tones. I thought perhaps this was from the planar magnetic driver in the mids known for its quicker decay, although it is plausibly more a case of the Omnium being highly sub-bass oriented with the mid-bass taking a detour at times. Bass guitars still have plenty of range though, yet I can see why some might consider the Omnium's bass to be somewhat lean. As such, I'd say this is a set which will work nicely for synth and EDM tracks, and I'd say the elevated upper treble also helps here, albeit the Omnium would not be my first choice for those whose music library comprises a lot of classic rock and heavy metal music.

I love my planar magnetic mids in headphones, and the HIFIMAN Arya line is one of the best in the world to put out accurate and natural—to me—sounding instruments and vocals. Some find it to have timbre issues though, and I can certainly see some vocals coming out overly forward, if not shouty. The Craft Ears Omnium, be it for better or worse, manages to render this experience in a set of IEMs better than I expected even knowing the inspiration behind it. A look at that frequency response might make you think this is not a well-tuned set. Logically, I see things that most people might even find troubling, if they were judging purely based on how it measures compared to some neutral-tuned sets. Yet the Omnium makes it work in a way I can only respect. It leans warm in the mids overall, with that slight bump and the dip thereafter adding some meat to male vocals and brass instruments, while that customary HIFIMANesque dip may be part of the wide soundstage I feel here. I am not sure that I like how wide it sounds though, as imaging could be more improved around the ears and I feel the height and depth are still bottlenecks. The Omnium handles layering with ease, and overall I'd say this is more analytical than the tuning suggests too, with well-recorded and mixed tracks getting their dues and poorly recorded ones revealing their issues.

The ear gain is prominent on the Omnium, so much so that it can actually sound bright to many despite the marketing materials suggesting otherwise. A lot of this has to do with excess 4-5 kHz energy that adds some glare to vocals and strings, in addition to percussion hits from cymbals. The mid-treble then gets relaxed, actually more so than the graphs above suggest, helping prevent sibilance and fatigue kicking in, yet the Omnium still manages to be extremely resolving. I keep saying how this feels like a special set, and a big part of it is because Craft Ears has managed to get it working despite some sections that don't gel well with me. The treble in general reminds me of the PMG Apx SE, albeit I'd say the upper treble will be less annoying for people even if they are sensitive there. This is a combination of a uniform and smooth presence, as opposed to a giant rise followed by a dip, and the drivers themselves. Something tells me if the Omnium used EST/MEMS/PZTs/planar magnetic drivers for the treble with this tuning style, things may have been less pleasant. The end result is a technical and emotional set that is somewhat of a unicorn, it's not for everyone and yet is likely to please far more people than those simply looking at graphs may think.


I mentioned before how the Craft Ears Omnium sounds unlike any other set I've tried, which also means comparisons are even harder to make. There are full-range planar magnetic IEMs which can give you that snappy, accurate sound for instruments and vocals, although they don't have the deep rumbling sub-bass the Omnium has even with EQ. Likewise, I dare say the Omnium's treble will be more amenable for treble-sensitive people. If you like bass though, then the 64 Audio Volür should be in your shortlist. It uses a dual dynamic driver setup for the lows in a true isobaric configuration which, paired with either the m15 or m20 apex modules makes for an extremely impressive bass rendition in terms of dynamic range, contrast, depth for individual notes, and resolution while maintaining a sense of slam and punch unlike any other in this price range, and even above to a good extent. The apex modules also allow for customizable tuning, and it's on the comfortable side too. But then we get a more colored tuning in the upper mids and treble that kept the Volür from being an easy winner, and that exact issue mentioned before with the upper treble spike following a dip before is what killed many interests in the set once they got to demo it. There are ways to mitigate it with tip rolling, but realistically neither the Volür nor the Omnium are going to please everyone. Both share some strengths, but overall the two together actually do a lot of good to where I can actually see a place for both in one's collection rather than going for a single set priced much more.

While the MOONDROP Solis 2 is priced closer to the Omnium, I do feel it's more a set for collectors and ardent fans, especially if you appreciate the jewelry and craftsmanship on offer there, than from a pure sound perspective. It rarely comes up in discussions too given how rare it is outside China, and instead I'd like to discuss two other sets in the form of the Campfire Audio Solaris Stellar Horizon and the new LETSHUOER Cadenza 12 2024 Edition (review in the works). Both of these are full metal shell IEMs, in case this is important to you, with the Solaris Stellar Horizon using a black and gold faceplate too and the Candeza 12 going for simple all titanium shells without any decorative faceplates. These are both significantly tamer in the bass compared to the Omnium, and actually end up more balanced overall. I'd say these two also lean warm, albeit the original Cadenza 12 was a better rendition of the warm/neutral tuning. The Solaris Stellar Horizon could do better with vocals though, with the lower treble and upper mids in need of some work before the rest of the frequency spectrum works out. This is a comfortable set too, so anyone willing to EQ might be interested in this knowing it is currently on sale as well. On the other hand, the Omnium easily bests it in detail retrieval and playback accuracy, and I do feel I'd rather have the Omnium even as a specialist set. The Cadenza 12 is a large set, albeit again is more likely to offer a comfortable and secure fit compared to the Omnium. If this was earlier in the year, I'd honestly say LETSHUOER possibly had the upper hand over the Omnium in terms of resolution and layering too, and I do feel timbre was more correct there. However, LETSHUOER has recently changed the drivers and tuning of the Cadenza 12 owing to some of the original drivers not being manufactured anymore, and the newer tuning isn't doing as much for me. I do think it is the safest choice of the ones being discussed here though, and it also has received a price cut recently to merit interest.