HiFiMAN HE6 Orthodynamic Headphone Evaluation Unit Impressions
Test Preparations
After reviewing previous impressions and lessons learned from other participants, I have decided that the best way to get the HE6 to shine would be to attach it directly to the speaker terminals using the supplied banana plugs of my Cary SLI80 to channel maximum power.
The Cary has been placed in Triode output mode instead of UL for optimum performance, as recommended in the Cary User Manual.
HE6 Test Environment Configuration
Cary 303T Pro SACD Transport in Solid State Output mode connected to Cary SLI80 via Whiplash Elite Reference RCA IC
Comparative Test Equipment Configuration
Stax SR-007 Omega Mk1
Cary 303T Pro SACD Transport in Solid State Output mode connected to RSA A-10 Thunderbolt II via Whiplash Elite Reference XLR IC (balanced). This particular A-10 has served as his demo unit sporting Ray’s own maxxed out tubes until our fateful encounter at Can Fest, where—driven by entirely altruistic motives, of course—I have decided to ease his burden of packaging and shipping all his gear back home and gratefully packed it up and brought it back to my home instead.
Sennheiser HD800 recabled via Whiplash Reference X TWag Recable in XLR-balanced mode=>S/E 1/8” adapter when connected to Cary SLI80
- Option 1 (S/E mode connected to Cary 1/8” HP out)
- Option 2 (Balanced mode connected to RSA Apache via Whiplash Elite Reference XLR IC (balanced) to front-panel XLR HP out
Sennheiser HD600 recabled via via Whiplash Reference X TWag Recable in XLR-balanced mode=>S/E 1/8” adapter when connected to Cary SLI80
Sennheiser HD650 recabled via via Whiplash Reference X TWag Recable in XLR-balanced mode=>S/E 1/8” adapter when connected to Cary SLI80
Test Albums Used
- Tierney Sutton: “Something Cool” SACD
- Bellan Sonus: “Enamoured” CD
Pre-Test General Comments
I do not have, nor do I plan to acquire a HE-5 or LCD-2, so I cannot comment on how the HE6 performs on this equipment from that perspective. I decided not to compare it with neither Qualia or R10s because of the different design philosophy behind these two out of production headphones and the fact that they offer a markedly different listening experience to that of the HE6 and I wanted to keep the focus on the HE6 as a baseline.
Some may be surprised by the inclusion of the HD600 and HD650 headphones, but before you rightfully claim that the HE6 belongs to a higher category, I would kindly remind you that these aren’t your grandmother’s HD600s. As I noted in my “Duel of the Xes” review, the $425 Whiplash Elite Reference X replacement cable, especially in balanced mode elevates the performance of these lesser models to close to top tier. In fact, I routinely use the recabled HD600s as a baseline prior to listening to a new pair of headphones I haven’t auditioned before, which is what I’ve done in this evaluation.
First HE6 Impressions
I am well aware that the HE6 sample reviewed here is a prototype and I’m assuming further tuning and refinement is taking place partially based on feedback received here. Clearly, the HE5 design and manufacturing process served as a baseline and that shows in external appearance and the materials used with the exception of the drivers themselves. While the final Bill of Materials and aesthetics and pricing remains a matter of speculation at this point, from my perspective, the overall level of comfort and presentation of the HE6 prototype had not yet on par with its competitors in the $1,000+ segment, perhaps with the exception of the LCD-2 (based on what I’ve been able to determine from several photos and impressions of other Head-Fiers). As several other reviewers noted, the weight of the HE6 is considerable and it lacks an adjustable headband to partially offset its distribution in a way the Stax O2 does.
I am not familiar with the type of connector the HE6 uses to attach its cable, but I wished it had the readily available HD600 or HD800-style connector instead so that those of us already invested in replacement cables could leverage them when the final version is released instead of having to invest in yet another differently terminated cable to accommodate the HE6. The stock cable seems to be on par with most of its competitors, meaning there should be plenty of room for improvement just on that front. I would have loved to have been able to try one of my TWag X cables to see what it can do to the HE6’s already impressive sonic performance.
Yes, it is impressive on this system, without the doubt. Far more impressive than what I’ve heard during my brief chance to audition it during the Charlotte, NC Can Fest when it was hooked up to a rather compact DAC/Amp Drew Baird had on his desk there. Once the EAT-powered Cary SLI80 properly warmed up in Class-A mode and I got accustomed to the heft of the HE6, these “ear speakers” have began to truly sing. Tierney Sutton’s “Something Cool” album on TELARC SACD is a challenging album to render and I played each track over and over again switching to different headphones and amps, as outlined above to see where the limitations of the HE6 were.
There were, as it turns out, precious few to point out. Bass rendering was smooth and precise enough with a bit on the warm side for an ortho. Slams have had just the right impact without being overbearing. Imaging and sound staging was impressive enough, although I would not quite put it at the same level as the TWag X recabled HD800 or as consistent as the A-10 powered Stax O2Mk1. On some tracks, interestingly, Sutton’s vocals seemed to float some in mid-air over the HE6 while remaining stationary on both the O2 and the rest of the Sennheisers. This is an interesting phenomenon I have not yet encountered. Plenty of mids and abundance of treble completed the spectrum of the HE6’s presentation, but instrument separation and transparency was a tad below to the O2 and roughly on par with the HD800s. It’s worth mentioning, though, that the A-10 had been connected to the Cary 303T via balanced XLR, while the SLI80 by necessity via RCA ICs, of the same make and grade and that may have played into the fact that while the HE6 presented a wide enough sound stage, it was not as well-defined to my ears as the O2’s. Not a huge difference, but noticeable, nevertheless.
Direct Comparison Notes
HE6 vs. O2Mk1
This was perhaps the closest sonic match despite being paired with different amps by necessity. The HE6 had a bit more forward and dynamic presentation of the two, but in smooth, vocal tracks the edge belonged to the O2Mk1. Treble rolloff was hardly noticeable and essentially on par for the most part, very impressive overall. Based on my previous encounters with the O2Mk2, the HE6 would have come out ahead in this comparison category, especially when paired with the A-10. Neither of these headphones have become fatiguing over extended listening periods, but overall, I would prefer the O2Mk1 as my number 1 choice out of these headphones.
HE6 vs. HD800
In order to accommodate the O2, I had to disconnect the Apache, which was configured to power the HD800 in pure balanced mode. So most of the later comparisons were made between the HE6 and the HD800 connected to the Cary (an XLR to ¼” adapter was used for the HD800). Essentially, the TWag recabled HD800 is far superior in comfort, presents better spatial imaging, standing second only to that of the Qualia. What even the TWag-supercharged HD800 cannot match is the superior bass and lower-midrange rendering of the HE6. There is no comparison in that regard and it is a big enough differentiator to rank the HD800 below the HE6 in overall sonic performance.
HE6 vs. HD600
The bass and midrange presentation that is so lacking in the HD800 flows in abundance out of the recabled HD600. Ray Samuels once mentioned to me that he uses these cans to tune his amps but until I got Craig’s Reference X cable I shuddered at the thought of reaching for the HD6xx cans. That is no longer the case, however, I’m not saying that the TWag recabled HD600 is superior to the HE6 sonically. I am saying, however, that in this comparison, on this system, to my ears, it finished 3
rd, just below the HE6. Why? Believe it or not, it has nearly the same breadth of sound stage out of the Cary (s/e) and earlier treble rolloff than the HE6 while lacking none of the traits that makes the HE6 so compelling. This isn’t as far fetched of a claim when you consider the typical street price of the HD650s around $400, when paired with a $425 cable, it does approach that magic $1,000 cutoff level established earlier. When paired with the Apache, the sound stage is even wider, roughly on par with the HE6 and the HD600 is remarkably neutral, neither forward, nor laid back. At any rate, the HE6 still provides a superior overall sound quality primarily of its extended treble performance.
HE6 vs. HD650
Move along, nothing to see here. Although the recabled HD650 is decidedly better than the stock version, it’s forward mids, recessed highs make it a nonstarter in this particular comparison so it drops to the bottom of the pile.
Final Rankings - Based on Overall Sonic Performance
- Stax O2Mk1/A-10
- HE6/Cary SLI80
- HD600/Apache and Cary SLI80
- HD800/Cary SLI80
- HD650/Cary SLI80
Summary
R&D in almost all fields and knowledge areas is based on an iterative approach due to a variety of reasons. As I have stated earlier, while I lack the necessary perspective to judge the level of progress made since the HE5 first appeared in the marketplace, I could only review how this prototype performs on its own and against some of my other full-sized headphones. There is a lot to be excited about the HE6 and this program alone is proof positive enough that Fang Bian is not only serious about executing his vision to gain global acceptance in the discerning audiophile marketplace by delivering truly world-class audiophile equipment that is designed and made in China, but well on his way to reach his ambitious goal.
Perhaps Sennheiser, Sony, Ultrasone and other manufacturers should institute similar initiatives to leverage this community to solicit useful feedback during the product-testing phase to influence their development in a positive way and create better products.