Fit and Comfort

Seen above is the Audeze CRBN on a mannequin head that I bought recently to better show how headphones would look on the human head. Note that it's slightly under average sized, so account for the discrepancies accordingly. As with all headphones, getting a good fit and seal is crucial, so make sure to properly use the pivot points and height adjustability of the headband and ear cups. In this case, the multitude of swivel and cup rotation options make for an extremely customizable fit for basically anyone. The oval plush ear pads are also very comfortable in use, and prevent your ears from hitting the inside of the cups too. This is crucial for reasons we'll get to shortly, but overall I'd rate the CRBN easily in my top three of most comfortable headphones tested to date. The suspension band combined with the average clamping force work well in letting you forget that these weigh 470 g—more than the LCD-5 that ends up less comfortable overall, and certainly more than the average e-stat set too. It's also a pleasure to hold in the hands and look at them too. As such, expect to get questions about the set, should you somehow find yourself in public wearing the CRBN along with an actual energizer. I'd also classify this to be a semi-open set of over-ear headphones that is best used in a quiet environment anyway.

Audio Performance

Audio Hardware

Electrostatic (e-stat) drivers are effectively a brand new category of headphone drivers when compared to the dynamic (moving coil) and planar magnetic units we've seen before on TechPowerUp. These do share a common feature to planar magnetic drivers in that you still have an ultra-thin diaphragm, but there are no physical magnetic traces here which enable single- or double-sided magnets to move it within an electromagnetic field. E-stat drivers rely on an electrostatic field instead and this typically relies on a capacitive/resistive layer that necessitates a large number of electron charge carriers. A push-pull transducer, as it pertains here, relies on the diaphragm placed between two stators which acquire positive or negative potential, depending on the audio signal itself. The diaphragm then moves towards the negative-charged (really more an inverted audio signal feed) stator and away from the positively-charged one to then allow it to move back and forth extremely quickly. The inherent advantage here is the stators are acoustically transparent in a good design, and thus there is very little physically between the diaphragm and your ears to make for a natural sounding set of headphones with ultra-low distortion.

In practice, however, things are not as simple. The coating composition and thickness as well as the gap between the stators and the diaphragm are highly important in the effectiveness of the drivers, even before tuning comes into picture. You would ideally want a thin, highly stable, and extremely uniform coating on one side to minimize uneven transducer motion and distortion. This means also that the electrostatic potential has to be strong enough in the form of either a higher bias voltage or reducing the gap between the diaphragm and the stators. The former is mostly out of hand for e-stat companies now given STAX went from the 230 V "normal" bias to the now-standard 580 V "Pro bias" that everyone follows, owing simply to the e-stat amps/energizers following suit. There are rare exceptions, such as from Warwick Acoustics which go higher but ultimately the adoption of 580 V means companies had to play more with the transucer type, and distance between the stators to get the desired sound signature. The limited space for the diaphragm to move back and forth in traditional designs is why you don't get a lot of bass extension and also why the typical e-stat set is associated with a bright and airy tonality.

I mentioned separately how Audeze worked with researchers with the goal of producing a non-metallic noise cancellation device for MRI subjects. Audeze has its own article with more specific details on how the CRBN differs from the norm, and effectively the now-patented use of a carbon nanotube suspension in the transducer not only reduces the overall thickness, in the absence of a necessary extra thin film on top but also results in higher charge carriers. The company thus has the luxury of more space for the diaphragm to move back and forth for an enhanced bass response, without necessitating in the diaphragm getting stuck onto either stator and producing static noises that are unpleasant to listen to, while also reducing the bass response tremendously. Earlier batches of the CRBN had complaints from end users about this phenomenon that may have been from Audeze not yet having smoothed out its production process for the CRBN's transducers. This could be from a variety of reasons, including the CNT type and diameter/length as well as how effective and concentrated the CNT suspension was. I have here an Aug 2022 batch CRBN unit that I am glad to report has no such issues, even when I jived strong to it on my head. If you found yourself facing this then you can follow logical e-stat steps of use including placing the headphones over your head first before plugging it into the source and then discharging any built-up static by touching the cable pins as demonstrated here. Still, I recognize that this is one of multiple hurdles that have kept users from dipping their toes into the e-stat pool, and you should be aware of this even if the CRBN as of the date of this review appears to be far less susceptible to this issue. I will wrap up this section by sharing with you this handy teardown of the CRBN driver assembly.

E-stat Sources, Frequency Response Measurements, and Listening

At this point you may have noticed that I didn't talk about how easy, or not, the CRBN is to drive off sources. This is because of the operating nature of these headphones which make them incompatible with more typical headphone amplifiers that simply do not generate voltage and/or current amplification within the range needed. But given the CRBN, as with any other STAX Pro bias set of headphones, requires 580 V fed to it, there is a much, much smaller pool of amplifiers to choose from. Audeze has provided a list of sources it has deemed compatible with the CRBN following in-house testing, and you will notice how many are from smaller outfits or even individuals in this wild west world of e-stat amplifiers and energizers. A lot of these designs also originated from STAX, and were updated along the way or simply brought into existence from engineers such as Kevin Gilmore, whose work has directly contributed to the Headamp Blue Hawaii Special Edition I ended up going with. This is a hybrid solid state and tube amplifier that I had the luxury of testing alongside several e-stat headphones recently and was immediately won over by. You can also go with solid state or hybrid sources as seen in the list, as well as a few that cater to both dynamic/planar and e-stat headphones too. Nearly all of these will provide enough juice to get the CRBN loud enough but, as with pretty much all other amplifiers, some are clearly better than others in terms of allowing the headphones to shine throughout the 20 Hz to 20 kHz frequency range of interest.

I will mention that I have a general preference for a warm-neutral signature, emphasizing a slightly elevated bass and smooth treble range, with detailed mids and good tonal separation. I also generally prefer instrumental music over vocals, with favored genres including jazz and classical music. My testing was done with the CRBN connected to the Headamp BHSE on stock Mullard EL34 tubes as well as upgraded Psvane EL34C red label tubes that I felt helped with bass extension further, which in turn was fed off the iFi Pro iDSD Signature as well as the recently released S.M.S.L SU-10 DACs connected to my PC. The headphones themselves were placed on the same test setup as used for my other headphone reviews, as seen in the equivalent section of my Audeze LCD-5 review.


As per usual, you can find my headphone frequency response measurements on VSG.squig.link, along with all the earphone measurements. Scroll to the bottom and choose different targets there, including two from Harman Kardon, developed after years of R&D. The Harman 2018 over-ear target in particular is a reference curve many headphone makers aim for now, but I find it too bass-boosted. As such, I am opting for the Harman 2018 curve with the bass target from the Harman 2013 curve, which is what is referred to as the "Harman Combined" target. Before we get talking about the sound signature of the Audeze CRBN, I want to briefly discuss the channel balance achieved here. You will notice how the left and right channels are pretty much identical throughout the test regime of 20 Hz to 20 kHz and even that tiny resonance peak deviation at ~6 kHz should be taken with a grain of salt given it can be attributed to the fit/seal on the ears as well as the coupler resonance itself. In practice I found perfect channel balance with this unit, and it's to be expected given Audeze tests individual drivers prior to pairing and assembly. Indeed, you can reach out to the company and provide the serial number to get the factory measurements for your specific unit too—a neat venture that I wish other companies would partake in.

The Audeze CRBN is a unique set of headphones and I can't state this enough. The frequency response above might look similar to those who have seen my reviews of higher-end planar magnetic headphones before, especially when it comes to that bass extension all the way down to 20 Hz and below—there's actual rumble in this jungle). Indeed, that straight line sloping down slightly would even make some feel it's not as bassy or slammy as a few other open-back flagships and yet this bassy behavior is simply unheard of in the typical e-stat set, for reasons mentioned earlier in this page. It's also quite detailed and responsive to where I thought the overall bass presentation was excellent, without going too much down the purely analytical route. There's plenty of speed and dynamic range to satisfy even the most demanding of audiophiles, while acknowledging that you won't get the heavy-duty impact from the likes of the Audeze LCD-4/LCD-5 w/EQ/Focal Utopia. The CRBN also takes well to EQ for those wanting more punch, but note that timbre here is not class-leading, to where you might not like the twang off bass guitars here as much as even some planar sets that themselves don't have timbre fans in the first place. Drums fare much better though with both leading and trailing notes getting due love, and this is where I was jiving hard to the CRBN, moving my head to the beats and then realizing this unit wasn't exhibiting the static noises earlier batch users were complaining about.

In fact I will go ahead and say that the CRBN is my favorite Audeze to simply relax and listen music to, and this accounts also for my time with the excellent LCD-5. It's not as detailed as the LCD-5 nor as slammy with EQ but that also means I am not suddenly picking up tiny imperfections in recordings, getting potentially fatigued by immense detail retrieval, or getting distracted by artifacts during the mixing process. The LCD-5 remains the best monitoring set of headphones in that regard and the CRBN is simply the more musical offering for audiophiles that share my library interests, by offering a slightly warmer tone complete with fast transients. This also means that the mids continue with engaging presentation and excellent channel/instrument separation where vocals are forward facing and image precisely in a wide cone around the ears and straight ahead. The larger cups and the open nature of the transducers also makes for very natural instrumental reproduction and a wider soundstage than the typical Audeze, yet I would not classify the CRBN as especially spacious. This does make the CRBN quite good for gaming and movies too, although female vocals can be, and more likely than not will be, shouty to the average end user. The slight 1 kHz honk and the ~10 dB pinna gain is aggressive, and your personal preferences will dictate whether you wish to EQ things down, leave it/enjoy it as I was able to with the warmer source that is the BHSE, or even dismiss the CRBN outright because it's far beyond your comfort zone here.

Perhaps what helped sway the CRBN in my favor further was the dip at 5 kHz which you might notice is part of my personal in-ear target too. I thought it helps keep the CRBN from being overly bright or sibilant in the lower treble but then things do get fairly dark to where I once again was surprised by how different this is from your usual e-stat that is a bright and airy set. I simply had to EQ by ear here to make my classical music sing and yet I wanted more. Piano key fundamentals were strongly represented but string instrument harmonics less so, even if I still think the CRBN is excellent for most jazz sub-genres. I wanted to feel that hang time of harps and viola notes breathing down before subsequent ones came in, and perhaps here too the e-stat timbre played a role. Goes to show that EQ isn't just a magic solution and that the CRBN, while still a set I clearly enjoy, remains genre specific and not perfect. I did appreciate the air in the upper treble when it comes to cymbals and harps though, as well as triangles in the few occasions they show up in music tracks these days.


Given my experience with flagship planar magnetic sets far more than dynamic and e-stat sets at the time of this review, I wanted to relate the CRBN better to the likes of the Audeze LCD-5 ($4500), the HIFIMAN Susvara ($6000), and the HIFIMAN HE1000se ($3000). The CRBN costs exactly the same as the LCD-5 and do note that these are MSRPs as opposed to street pricing, which is going to be lower. I briefly touched upon the CRBN vs LCD-5 before, but in a nutshell—the CRBN is more specialized for music catering to the likes of classic rock, jazz, and male vocals in particular with potential benefits also to female vocals depending on your HRTF. The LCD-5 is a detail king that, with EQ, I maintain is a blank canvas that can be your favorite analytic tool as much as a slammy set with nautral vocals too, even if it does lose out to the CRBN when it comes to staging and overall presentation. The HE1000se is another highly resolving set that unfortunately goes the other way as the two Audeze flagships in being overly bright as opposed to dark, and becomes a worse challenge to correct, to where it became a one-trick pony and not a set that I'd personally recommend for the money. Arguably the CRBN's biggest challenge comes from the Susvara which, as with the CRBN being a planar-like e-stat, is somewhat of an e-stat-like planar. It's the best tuned set of headphones out of the box that I have tested to date, and only the Sennheiser HE-1 goes beyond it among all headphones I have ever listened to. The Susvara is also more relaxed and better suited for the likes of jazz too, but bests the CRBN when it comes to classical music, and indeed most music. I'd still prefer the CRBN for its more natural and engaging presentation with the e-stat transducer as well as the bass response here laying it thick and musical, but overall for the same money I'd take the Susvara that is also easier to find sources for, at a more reasonable price.


Now we come to the other e-stats I have here in various stages of review, including the HIFIMAN flagship Shangri-La (Sr.) that costs a whopping $18,000 by itself and comes as part of a $50k set with an amplifier that is intended to take on the Sennheiser HE-1. The Shangri-La is the epitomy of everything you think of when an e-stat headphone comes to mind, if at all, with effectively a concert playing around your head if you close your eyes and imagine yourself to be in a hall instead. It's also tuned on the brighter side and arguably just wrong in the upper mids though so the strengths and weaknesses of the CRBN are somewhat swapped with the Shangri-La. The build quality on the Shangri-La also leaves more to be desired—especially when it comes to the attached cable that is flimsy and inside thin sleeving akin to a cheap PC fan cable. The same could be said about the Shangri-La Jr. that costs slightly less than the CRBN and, despite a much better overall tuning, ends up being somewhat lacklustre and not really that much fun to listen to for the money it asks for. What is more intriguing here, and again you can go to my measurements database for closer comparisons, is the Nectar HiveX that is made by a single guy in the US, and costs nearly an order of magnitude lower. The HiveX also goes for a bassy signature and does so simply by leaving more room between the stators and the diaphragm. This also means it's more susceptible to the sticking phenomenon, so you have to be more patient with it, and A/B comparisons show the CRBN to be far more resolving, yet worse tuned as an all rounder. For the money there is no doubt that I would buy the HiveX although the issue also remains here that no one would logically spend ~$680 on e-stat headphones and then ~$7-8k on the amplifier that is getting you this experience. I heard first hand how much worse the same e-stat set can sound off clearly worse executed sources—some that even cost more than the BHSE—so really the HiveX is an underrated set that unfortunately I expect won't have its full potential realized by most customers. I will also mention that I heard multiple different STAX units at a trade show recently, including the excellent new flagship SR-X9000 that I thought was the best e-stat headphones there, if not the best overall set with the BHSE, but take that statement with a grain of salt given the different listening environments and audio chain involved.