The CRBN tuning will destroy the common perception that all electrostatic headphones are bass-light, overly thin, and ethereal sounding. Only the 007 MKII will come close to offering the type of dense and meaningful low-end performances that the CRBN can deliver and even then, it’s an entirely different type of bass performance.
That being said, the CRBN is not all about that weighted delivery, it also has some great timbre. Neigh, a gorgeous timbre at that and one that creates a very natural and balanced sound signature without any loss of that essential electrostatic penchant for excellent detail and accurate timing.
This is also an electrostatic headphone that does extremely well with vocals. The imaging and presence are excellent, much better than the Stax SRM-007 MK2’s more muted positioning as well as sounding richer and more textured than the DCA VOCE’s dipped midrange tuning.
The top-end treble will sound relatively relaxed for those used to the airy clean Shangri-La Jr shimmer for example. The detail is there but it is not pushed down your throat or with high levels of timbral contrast. That in turn keeps CRBN coloration more to the smooth side with very little in the way of any unwanted sharp partial overtones.
Your system setup will produce some variations on the above theme so keep that in mind. The CRBN is more power-hungry compared to some other electrostatic headphones I have here.
That means portable options like the solid-state Stax D10 will give you a clean sound with enough volume but rob you of that desired bass extension and dynamics in comparison to stronger desktop options.
There is a degree of familiarity with the measurements of the CRBN and you might find similarities with the LCD-5 tuning with that nod to the Harman Target Response Curve.
Audeze has kept the CRBN bass response very linear so you will not find any Harman-preferred elevated sub-bass below 100Hz. Rather this is a very subtle upward trajectory up to 1k consistent with the Audeze house sound with their latest planar models.
It does give lower-mid instruments some excellent presence and body without having to push the bass hard to compensate. Something that the 007 MK2 tends to focus more on and whilst it is a ‘bass monster’ it can overly dominate. The CRBN curve digs deep, is not as punchy, and is a bit warmer with no mid-bass rise, but it sounds more coherent to my ear.
From 1-4k the CRBN offers plenty of head gain but not aggressively despite perhaps pushing over the Harman response curve a little. The vocal presence is not in your face but it does have a front-row appeal which I prefer, especially if the bass has some authority.
It is quite a contrast to the VOCE which dips that very same range, hollowing out the vocals a little and pushing more emphasis to spatial cues at the extreme ends of the stereo image. It also sounds clearer in the mids compared to the 007 MK2’s which can get drowned out by the heavier bass tuning.
Treble tuning beyond 6k is a few dB below Harman until 10-12k where the headroom is very good indeed. With mellower tube setups it might come across as a shade relaxed. Compared to the Shangri-La Jr it is less dominant so detail perception might not be as strong with a slightly softer attack and less high-contrast coloration.
Possibly the most un-electrostatic timbre I have heard in an electrostatic headphone in a long time. I hesitate to say it sounds like a ‘normal headphone’ because there are reasons why people buy and enjoy electrostatic headphones and I am one of those people also.
However, the CRBN timbre just sounds so natural, dense to a degree on the low-end also but with some beautifully smooth and inviting instrumental and vocal timbre.
I heavily recommend feeding any energizer you have with a good quality R2R DAC such as the Holo Audio Spring Series to hear just how well the CRBN fleshes out the fine detail within each instrument and singing voice.
The tone can err to the rounded and euphonic side if you feed it too much tube amp and R2R DAC. The CRBN is sensitive to system setups though it never really deviates too far from that rich and weighted delivery.
My older VE Enterprise E Lite produced a slightly cleaner tone with the Holo Spring DAC 2 compared to the Shangri-La Jr tube amp. That pairing did help with bass definition and for those who would want something a little less euphonic and more neutral-sounding in the mids.
Mids and higher pitching timbre lack any overt high-contrast coloration. Again, the tone is more liquid to my ear with a slightly warm hue, neutral levels of decay, and a slightly diffuse quality to the imaging as a result.
The CRBN does not have a treble coloration that is imbued with a ton of hard-edged shimmer. Cymbal crashes, hi-hats, and tambourines sound more even-harmonic than odd with a very pleasing and life-like tone.
Staging & Resolution
I would describe the CRBN staging as life-like with vocals slightly to the force, supported by an impressive bass fundamental, accurate separation, and a rounded rather than stretched imaging performance.
Certainly, in terms of power, the CRBN is deeper sounding than the Shangri-La Jnr. It has a more forward midrange presence compared to the VOCE and offers better imaging and clarity than the 007 MK2. It is not as airy and ethereal sounding as the Jr but it successfully avoids that slightly metallic after-effect of the 007 MK2’s slightly booster 8-10k treble tuning.
Overall, your listening attention will be drawn more to the CRBN bass and mids presence, especially vocals than anything screeching at you from the highs. Low-note saxophone passages also sound immensely detailed and vibrant with the CRBN. The width is very good but not quite as extreme as the VOCE or dynamic driver monsters such as the HD800.
The CRBN staging is source sensitive at times so matching will vary that outcome a little. This is a demanding headphone for power so the more you feed it the more dynamic it will sound on the low end and the blacker the background will become.
For example, the Stax D10 pairing was quite clean in its performance with the CRBN but the low-end lacked the dynamic range and power to satisfy compared to stronger desktop offerings such as the Stax SRM-007tII.
In turn, the SRM-007tII sounded a little more neutral in its staging depth with a little more treble energy compared to the Shangri-La Jnr. The HIFIMAN amp, in turn, sounded more mid-forward with the CRBN than the neutral but more holographic-sounding VE Enterprise E Lite.
Testing was done with 3 electrostatic desktop amplifiers including the Shangri-La Jr dedicated Pro bias compatible tube amp, the Stax SRM-007tII, and the VE Enterprise E Lite, (a 325Vrms RMS capable tube amp and somewhat similar to the old Stax SRM-T1 but with a BFT input stage, not JFET).
All three were connected in balanced mode switching between two R2R DACs, the Holo Audio Spring 2 Wildism Edition and the Musician Audio Pegasus. These two DACs offer a fairly natural to slightly warm and rich tone in combination with the 3 tube amps.
The final pairing was the Stax SRM-D10 solid-state portable energizer and ES9018 implemented internal DAC.
From all tested pairings I quickly realized that the CRBN is probably one of the more demanding electrostatic headphones when it comes to power. Usually, that accolade goes to the DCA VOCE, however, on all the tested desktop amps the CRBN needed a few more dB to sound optimal and correctly volume matched.
The portable 200Vrms D10 did manage to cope with CRBN in terms of volume and the performance was not too shabby either in terms of resolution.
However, I am not a fan of the built-in ES9018 DAC’s neutral tonal synergy with the CRBN and would prefer to use it purely as an amp with a 2V line-in from a superior DAC or DAP. The core sound is much more solid-state or clean sounding as you would expect but the bass dynamic felt a bit flat with the CRBN.
Both the 340Vrms max output tube-based Stax SRM-007tII and Hifiman’s own Shangri-La Jr hybrid tube amplifier injected a lot more ‘bounce for your ounce’ on the low-end with a superior dynamic range which is what I suspect buyers would be looking for with any CRBN pairing.
Each of the desktop pairings brought a little something different to the table but upfront caveat time, sources do matter a lot with this pairing as it was with the Shangri-La Jr during its review pairing process.
I tend to prefer an R2R DAC behind all 3 amps just to take the edge off some of that classic e-stat timbre you can get with the 007 MK2 upper treble and some of my older Stax headphones such as the Stax SR-303.
That is not necessary with the CRBN with that smoother tone. The treble is nicely balanced for delta-sigma DACs such as the Little Dot DAC VII which has tons of low-end power and dynamic range. This is a vivid and energetic match with the CRBN and two of the stronger amps we used such as the Enterprise E Lite and the Shangri-La Jr amplifier.
However, with DACs such as the Holo Spring 2 and the Pegasus, the emphasis is more on a natural heavily textured sound which does very well in fleshing out the note texture on the CRBN.
I would say the Shangri-La Jr amp is probably the most tube-like in its delivery with a bit more warmth on the low end and a slightly softer attack compared to the punchier and more precise sound of the Enterprise E Lite.
The Jr/CRBN combo vocals were a little further forward on the Jr amp and marginally more euphonic, and ‘fleshier’ sounding. Whereas the E Lite was comparatively neutral in both coloration and imaging though still not as dry sounding as the SRM-D10 portable amp’s performance.
Of the three desktop amps, the Stax SRM-007tII was perhaps the most neutral of the three tonally with a slightly flatter bass presence, cleaner midrange timbre, and a bit more treble presence. The mids came more to the fore on this CRBN pairing and it did sound a shade more intimate or not as expensive as the other two amps.