The TRUTHEAR x Crinacle ZERO RED are wired audiophile IEMs. They're an updated version of the TRUTHEAR x Crinacle ZERO, with the manufacturer claiming that these have undergone much more than a simple facelift. While they retain the same dual-driver design, changes in the voice coils and crossover circuits have resulted in a new tuning that strays from the original's mission to stay close to the 2019 IEM curve. This edition instead represents the kind of less bass-forward tuning that's preferred by Crinacle, one of the internet's most well-known IEM tuning experts. That said, for those that might miss the low-frequency oomph of the previous generation, they come with a handy 10-ohm resistor that can boost the bass response.
Our Verdict
The TRUTHEAR x Crinacle ZERO: RED are okay for sports and fitness use. They're lightweight, comfortable, and have a stable fit. They're also well-built, though they lack a certification against water or dust damage. They're primarily hampered for this use by their wired design, which is susceptible to tangles and snags. Although the cable is detachable, it can easily be yanked while in motion, which can result in damage to the connectors. They also don't have any dedicated physical controls for skipping tracks or pausing while you're mid-workout.
- Comfortable, stable fit.
Cabled design can be cumbersome.
The TRUTHEAR Crinacle ZERO: RED are decent for travel. While they're comfortable, portable, and come with a convenient carrying pouch, they struggle to isolate you against a lot of background noise, especially lower-frequency sounds, like the rumble of bus engines. They're a little better at blocking out the mid-range sounds of a busy street, but the passive isolation provided by their in-ear fit still falls flat when compared to ANC-equipped alternatives.
- Comfortable, stable fit.
- Very consistent audio delivery.
- Minimal isolation against low frequency sounds.
Cabled design can be cumbersome.
The TRUTHEAR x Crinacle ZERO: RED are disappointing for office use. Despite their comfortable, stable fit and solid build quality, they struggle to block out common office sounds, like background chit-chat and the scraping of chairs. They also don't have a mic, so you'll have to switch to a headset or use the built-in mic of your connected device to take calls (if it has one). That said, they barely leak any audio, so you won't have to worry about disturbing your colleagues even if you blast your music.
- Comfortable, stable fit.
- Minimal isolation against low frequency sounds.
No built-in microphone.
The TRUTHEAR ZERO: RED are wired-only headphones; you can't use them wirelessly.
The TRUTHEAR ZERO: RED are passable for wired gaming. Thanks to their wired design, they have virtually no latency. They also feature a comfortable in-ear fit suited to long gaming sessions. Their balanced sound profile is great for rendering bass frequency sounds, like explosions, with plenty of substance without overshadowing the detailed mid-range. Unfortunately, they don't have a mic, so you'll need an aftermarket cable or standalone mic if you need to speak to teammates.
The TRUTHEAR ZERO: RED have satisfactory audio reproduction accuracy. Their frequency response doesn't deviate from their balanced sound profile much—minor fluctuations in the treble may sharpen sibilants, depending on pitch. Their L/R drivers are fairly well-matched, but there are some mismatches in their high-treble frequency and phase response. As we're less sensitive to the top end over time, you likely won't notice serious issues in everyday listening. The earbuds produce low distortion, even at high levels, reproducing audio cleanly. As in-ear headphones, they don't interact with your outer ear to improve immersion.
The TRUTHEAR ZERO: RED have alright noise isolation performance. Their foam tips do a decent job passively attenuating treble range noise; however, the earbuds' lack of ANC doesn't supplement the virtually nonexistent mitigation in the bass and mids. In everyday use, they won't do much against bus or plane engines while traveling, nor footsteps in the office. On the plus side, the earbuds don't leak much audio, rarely exceeding the noise floor of a quiet room.
The TRUTHEAR x Crinacle ZERO: RED don't have an integrated microphone.
The TRUTHEAR ZERO: RED's frequency response consistency is impressive. If you take the time to find the right ear tips and get a good seal, the earbuds' performance will remain consistent between reseats. Our frequency response measurements will also be indicative of most people's perceived listening experience.
Performance Usages
Changelog
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Updated Nov 18, 2025:
The Build Quality section was updated to compare the CrinEar Daybreak.
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Updated Jul 29, 2025:
We've updated the Sound Profile box with a link to a downloadable folder of EQ settings that will help you match these headphones' frequency response to different target curves available in our Graph Tool.
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Updated Apr 25, 2025:
This review has been updated to Test Bench 2.0, which adds the following tests: Stereo Mismatch, Group Delay, Cumulative Spectral Decay, PRTF, Harmonic Distortion, and Electrical Aspects. We've added new performance usages and updated the text throughout the Sound tests and side-by-sides.
- Updated Apr 25, 2025: We've converted this review to Test Bench 2.0, which updates our sound tests and adds performance usages. You can read more about this in our changelog.
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Differences Between Sizes And Variants
The TRUTHEAR x Crinacle ZERO RED are wired IEMs designed to deliver audiophile-quality sound. Not to be confused with the original TRUTHEAR x Crinacle ZERO, these buds come in one color variant: 'Red.' The two variants boast an almost identical feature set, with the main point of differentiation being the tuning. You can read more about this in Sound Profile.
If you encounter another variant of these headphones, please let us know in the comments below, and we'll update our review.
Popular Headphones Comparisons
The TRUTHEAR ZERO: RED are wired IEMs. They're a re-tuned version of the TRUTHEAR x Crinacle ZERO, so comparing them to the original version is natural. The 'RED' features a tuning that's less focused on following the Harman 2019 IEM target curve and developed instead with Crinacle's own listening preferences in mind. As a result, the new version reins in the original's buoyant, in-your-face bass response and replaces it with something more balanced. The treble range is also more veiled. Besides a change in the color and design of the decorative panel and the inclusion of the 10-ohm resistor, there are no other differences in features. Those with a bigger budget who desire a more prominent treble response might also want to consider the MOONDROP Blessing 3, although they're considerably more expensive.
If you're looking for more headphones, check out our recommendations for the best audiophile headphones, the best headphones for music, and the best wired headphones.
The TRUTHEAR x Crinacle ZERO: RED are a better choice for fans of bass-heavy genres than the TRUTHEAR HEXA, which lacks a little body in their low end. On the other hand, Jazz fans may appreciate the slightly more detailed treble of the HEXA. The RED are a bit cheaper than the HEXA, but the HEXA are slightly better at blocking out noise, though neither pair have ANC.
The TRUTHEAR x Crinacle ZERO: RED and the TRUTHEAR x Crinacle ZERO are, by and large, the same pair of IEMs, albeit with different tunings and a slight difference in noise isolation performance. They're both comfortable, well-built, and stable-fitting, but the RED variant aligns more closely with our target curve, with a more controlled bass in particular. They're also better at isolating mid-range frequencies, like the chatter of your colleagues in an office setting. On the other hand, the RED have a recessed treble that will be less appealing to people who like a more excited sound with a bit more sizzle. It's worth noting that the RED variant comes with a 10-ohm impedance adjustor, so you can always purchase this variant and use the adjustor if you prefer a more bass-heavy sound.
The MOONDROP Aria and the TRUTHEAR x Crinacle ZERO: RED are similarly priced wired audiophile IEMs. While the MOONDROP are more comfortable and deliver audio more consistently, the TRUTHEAR do a better job of blocking out external sound across the entire frequency range, though neither is particularly exceptional at noise isolation.
The TRUTHEAR x Crinacle ZERO: RED are better overall in-ears than the KZ ZS10. The TRUTHEAR are more comfortable to wear for extended listening sessions. They also feature a 10-ohm adaptor for additional tuning, in case you prefer a more bass-heavy sound. The KZ have a slightly better build and a very durable plastic casing.
We've upgraded our Headphones Test Bench to 2.0! This update brings several key changes to our tests and usages, making it easier than ever to interpret our sound results based on your personal preferences. You'll also find a brand-new interactive graph tool featuring multiple targets (including our own!) for you to explore and compare.
For a full breakdown, check out our changelog, which includes detailed commentary from our test designer explaining the rationale behind our update.
We'd also love to hear your thoughts: your feedback helps us keep improving, so join us in the comments!
Test Results
While the original TRUTHEAR x Crinacle ZERO were designed to closely follow the Harman 2019 IEM target curve, this new edition is a deliberate and intentional deviation from this tuning. Crinacly describes this new tuning as 'more palatable' in a video showcasing the ZERO: RED, which, in this case, translates to a similar sound profile that's more reined in. Their balanced sound signature has a less exaggerated low end and more subdued treble compared to the Harman IEM target curve.
Accommodations have been made for those who prefer a more bass-heavy sound profile, too, as these buds come with a 10-ohm adaptor that alters the impedance slightly to add more low-end thump to the sound profile. It's more of a subtle boost than a drastic change in sound, but it'll also lower your output level slightly, which you'll need to adjust for.
Grab our downloadable EQ settings folder to adjust these headphones toward different frequency response targets featured in our Graph Tool.
These in-ears have excellent frequency response consistency. Once you achieve a solid fit with the right pair of ear tips, you'll be treated to consistent audio delivery every time you use them. While the plot shows deviations in the high-treble, they're mostly due to the difference in frequency response between both drivers rather than the seal being compromised—the normalized value used to calculate consistency for IEMs is the averaged response of both drivers.
The bass-range target compliance is exceptional. The tuning of the TRUTHEAR x Crinacle ZERO RED is more closely aligned with our target curve than that of the TRUTHEAR x Crinacle ZERO. The low- and mid-bass are slightly overemphasized, giving kick drums a little extra thump and punch. A small dip in the high bass keeps basslines from sounding boomy and bleeding into the mids. In songs like Justice and Tame Impala's Neverender, both the kicks and the bassline sound present and powerful but never overpower the rest of the mix.
The mid-range target compliance is remarkable. The low-mids are ever so slightly recessed, which helps prevent dense mixes from becoming cluttered. The mid-mids follow our target almost perfectly, so vocals are present without sounding boxy. Finally, the high-mids are slightly boosted, which ensures instruments sound clear. On tracks like Alesis by Mk.gee, the vocals sound distinct and differentiated from other mid-range instruments like snares and synthesizers.
The TRUTHEAR x Crinacle ZERO RED have superb treble target compliance. The lower part of this range closely follows our target, meaning instruments sound detailed but not harsh. On the other hand, the mid-treble is a bit recessed. Some users may like this, as it lends these IEMS a slightly warm sound and reigns in sibilance, but it can also make vocals and cymbals sound dull. If that smoother sound appeals to you, you might also want to consider the THIEAUDIO Monarch MKIII.
The peaks and dips performance is very good. The TRUTHEAR ZERO: RED's response follows their balanced sound profile well. A small dip in the high bass is likely where the drivers cross over, but it doesn't affect the sound much. At the other end of the spectrum, a small peak in the low treble and a bigger peak in the mid-treble mean sibilants might be slightly harsh, depending on their pitch.
The TRUTHEAR x Crinacle ZERO RED are well-matched. There isn't much difference in amplitude between their L/R drivers, so you won't experience general directional bias of sound objects in the stereo image. That said, frequency response mismatch between the drivers in the high-bass and low-mid can create gaps in the stereo image. While the headphones have a high weighted phase mismatch value, the L/R drivers' phase responses shift relative to one another primarily in the high-treble, where our sensitivity diminishes over time—at worst, you might notice reduced resolution in the positioning of whistle notes. Additionally, driver matching is a measure of quality control, so performance can vary from unit to unit.
The group delay performance is decent, mostly falling below the audibility threshold. However, the dip in the high-bass indicates phase shifts in both drivers that contribute to the notch in their frequency response in the same region. You likely won't notice any colorations from group delay issues in everyday content, with both drivers reproducing tight bass and transparent treble.
As with other in-ear monitors, the TRUTHEAR ZERO: RED have a very bad passive soundstage performance. By design, they bypass your outer ear, meaning there's no interaction between sound waves and your pinna. The resulting soundstage is small, closed-off, and unnatural-sounding.
The TRUTHEAR x Crinacle ZERO RED have outstanding harmonic distortion performance. They can reproduce audio cleanly across the audible frequency spectrum, even at high levels.
These earbuds don't require an amp to drive them and can playback audio at high listening levels on mobile devices or laptops.
These are the settings used to test the TRUTHEAR ZERO: RED. Our results are only valid when used in this configuration.
The TRUTHEAR ZERO: RED have a very similar teardrop-shaped design to the original TRUTHEAR x Crinacle ZERO. They feature the same braided, detachable cable as their sibling, but their 3D-printed resin cavity is covered in a decorative panel that's finished in a strikingly figured crimson red. Internally, there's a similar configuration of drivers with a 10mm dynamic driver handling bass frequencies and a 7.8mm driver responsible for the mids and treble.
The TRUTHEAR ZERO: RED have a comfortable in-ear fit. You can choose from the six sets of silicone ear tips and one set of foam tips to ensure a great fit, but we found the foam pair provided the best seal. Their shape is well-suited for most ears, but the wire connector would sometimes slip off the bud itself when the fit was adjusted, especially in a twisting motion.
These in-ears are exceptionally portable. They're extremely lightweight and take up minimal space in a bag or pocket. You can also detach their cable for separate storage, and they even come with a carrying pouch.
The included carry case is identical to the one provided with the TRUTHEAR x Crinacle: ZERO. It's made of a supple faux leather material with a soft velvet interior. It's designed more for storage than protection, and there's nothing in the way of extra storage compartments.
These buds have a good build quality. The enclosure is made of a sturdy 3D-printed resin with a glossy plastic exterior. You get sets of foam and silicone tips, and both materials feel reliable, although the foam tips are prone to becoming somewhat dislodged. The nozzle that they're attached to is on the longer side, too, so it might take some trial and error if you plan on using a non-stock pair of ear tips. The cable is braided and double-sided, but its construction is a little flimsy and prone to wear and tear. The connectors used to attach the cable ends to their respective earbuds also need to be handled with care. When connected, they don't form the tightest fit either and tend to slip out of place when handled. There's a similar lack of friction with the 10-ohm adaptor, which can feel wobbly when plugged in due to its length. For a more upgraded build with aluminum nozzles, the CrinEar Daybreak feels more solid.
Once you find the right pair of ear tips, these buds have a stable fit. We tested them using the foam tips and found that they can stay in place during moderate to intense exercise. They'll stay in your ear during a light jog, for example, but you run the risk of snagging the cable on something, which will dislodge them from your ear.
- TRUTHEAR x Crinacle ZERO RED headphones
- Detachable cable
- 3x sets of thick diameter silicone ear tips
- 3x sets of thin diameter silicone ear tips
- 1x set of foam ear tips
- Documentation
- Carrying pouch
- Filters
- 10-ohm resistor
The TRUTHEAR ZERO: RED have a decent noise isolation performance, surpassing their predecessor's, but falling short of the TRUTHEAR HEXA's. While they don't have an ANC feature, their in-ear fit means these buds provide some passive isolation against ambient sound. As a result, they block minimal amounts of bass-range noise but do a better job of isolating against mid-range sounds. They're great at blocking out treble-range sounds, like fridge hum. Their improved noise isolation performance compared to their predecessor is likely due to a change in the makeup of the foam tips. While they look identical to those that came with the previous generation, these new tips have a little less spring to them. You can see a graph of our results comparing the performance of the foam tips and silicone tips here. While they block out a similar degree of noise in the bass and mid-ranges, the foam tips provide more isolation against treble range sounds, especially if they're loud.
The TRUTHEAR ZERO: RED struggle to block out everyday sounds. They struggle to block out the roar of airplane engines and office sounds, like chatty coworkers and chairs scraping. That said, they're better at blocking out street noise sounds, like blaring car horns and traffic.
The leakage performance is excellent. The leakage is concentrated in the high-mid range, so escaping audio sounds thin and lacking in body. However, the overall volume is so low that others around you won't be disturbed by your audio, even if you're in a quiet environment and cranking your tunes.
While these wired IEMs don't come with a companion app, Crinacle collaborated on the MOONDROP x Crinacle DUSK, which have an app that lets you customize their sound via a graphic EQ and presets.
The TRUTHEAR ZERO: RED come with a detachable braided audio cable. It's a 1/8" TRS connector, so you'll need a separate mic to input audio. They also come with a wired 10-ohm resistor that you can use to increase the bass, which lowers the output somewhat. The resistor uses the same 1/8" TRS connection and can be plugged directly into the cable.
These in-ears are compatible with PCs via a 3.5mm jack. However, you'll need to purchase a separate mic to input audio.
These headphones only support audio when connecting their 1/8" TRS cable to your PlayStation controller. If you want to send audio in addition to receiving it, you'll have to use an external microphone.
These buds only support audio when plugged into your Xbox controller's AUX port via the included audio cable.