Hardware Reviews

HEDD Heddphone Two with AMT magic

HEDD Heddphone Two headphone review https://the-ear.net

HEDD Heddphone Two headphones

I don’t often get over-excited by headphones, using them only when listening via loudspeakers is not possible for whatever reason. However, at the Dutch Audio Event last autumn I discovered some rather amazing German headphones using AMT drivers, my preferred type of high frequency drive unit for speakers, rather than more conventional planar or dynamic types. When the chance came for an exclusive UK review of HEDD’s new design, I couldn’t resist trying them out at home. Would they sound at least as good as they had in Eindhoven?


Heinz Electrodynamic Designs (HEDD) is perhaps not very well known in the UK, which is a shame because it should be. It’s a German manufacturer of high-end studio loudspeakers and Heddphones, founded by Klaus Heinz and his son, musicologist Dr. Frederik Knop. The company has been designing and building its products in Berlin since 2016 and has some really rather advanced products in its catalogue. I am struck by the Type 20 Mk2 active speakers which have a DAC and DSP that allows them to do some magic to the soundstage and imaging with zero-phase filtering. But that’s for another day.

HEDD Heddphone Two headphone review https://the-ear.net


The Heddphone Two is the culmination of three-years of R&D work to refine every aspect of the original model for an improved version. Thankfully a 25 per cent weight reduction has been possible by employing ultra-light materials, such as carbon fibre and magnesium. There’s also a new Air Motion Transformer (AMT) driver, reconstructed from the ground up. A key facet of the design is the smart strap system. This permits personalised height, width, curvature, and clamping pressure, to achieve a custom fit that’s intended to be comfortable even for prolonged use.

Then there is something called VVT (see below) which allows the AMT drivers to achieve an even frequency response across the audio spectrum through clever implementation of the driver’s geometry to allow folds to vary in width and depth. The result is claimed to be the world’s first full-range AMT headphone.

I asked about burn-in because clearly my Heddphone Two review sample was fresh off the production line. “Technically and mechanically, we have zero proof of any burn-in effect”, says Klaus Eulenbach who demonstrated them at the Dutch event. “We let each unit play for 15 minutes before the final quality control, and we measure every pair, as well as every driver and even every ear pad, for best possible matching”, I discover.

HEDD Heddphone Two headphone review https://the-ear.net

To be fair, I allowed the Heddphone Twos to acclimate to my room temperature and humidity because that can effect acoustics, especially so for the ear pads, I was told. But the bottom line is: “Our best advice is to wear them!”

Air Motion Transformer

I am well aware of AMTs used as loudspeaker tweeters; indeed, some of my all-time favourite designs rely on them for HF output. But in a headphone? That’s something new to me. It uses a folded Kapton polyimide film diaphragm to create a design of around 40 Ohms impedance and 89dB/mW sensitivity so a meaty amplifier will be a bonus if you like plenty of headroom.

Klaus patiently explains: “We have changed the geometry of the folds to adjust the tuning. We call it Variable Velocity Transform (patented), so the translation on how the air is pushed isn’t exactly the same as in a speaker application. While our tweeter vibrates at four-times the speed of what actually reaches your eardrum, the air squeezed between the folds of the HP2 is variable.

“There is another secret we implemented in the transition to the Heddphone Two which is not disclosed because we don’t want anybody to copy it. But we have managed to stiffen the polyamide membrane without increasing mass, resulting in far less distortion in this version. It’s a newly developed driver.”

HEDD Heddphone Two headphone review https://the-ear.net

On the subject of distortion, one key advantage is that the driver moves less in amplitude for the same dynamics compared to conventional drivers which measurably translates to less overshoot and less decay. According to HEDD, distortion is basically non-existent in the bass, even when driven at very high SPLs. This was already the case for the original and in the Heddphone Two, they claim to have also reduced the audible distortion at higher frequency. This, it is hoped, will be translated as greater clarity and better separation.

Another engineering change for the new model is the overall tuning which has been steered more towards professional studio users, that is to focus on midrange accuracy. HEDD are pleased to have created an overall flatter response which is more accurate, albeit slightly forsaking audiophile ‘wow’ factor, however this can be added through the use of some EQ if desired.


First impressions are that these are large open-backed headphones, certainly for home-use. The packaging is in the super-luxury bracket and exudes a feeling of quality. I also appreciate that various adaptors are included, rather than being a cost-option as other manufacturers feel necessary. Thus, it’s possible to use the Heddphone Twos straight out of the box with a wide range of sources whether they need large or small, balanced or unbalanced connection: 4.4mm balanced jack, 6.35mm unbalanced, 4-pin XLR or 3.5mm TRS. All bases are covered.

HEDD Heddphone Two headphone review https://the-ear.net

I began my listening using a Hegel 190 integrated/streaming amp and was immediately impressed by the sound of the Heddphone Twos. I had been warned that the treble might sound ‘brittle’ with some sources, but instead I found the overall balance to be slightly warm, inviting and highly involving.

Sound quality

From the first few notes it is clear that HEDD have focussed on midrange accuracy, for me the most important part of the audio spectrum. The detail through the Heddphone Twos is incredible and there’s a sense that the performance is very intimate. Overall, these headphones clearly intend to reproduce the source material as accurately as possible. I enjoyed many of my favourite classical albums, none more so than Schubert’s Piano Trio in E flat major performed by the Beaux Arts Trio (Phillips from 1985). This is as good as I’ve ever heard this recording on headphones and better than I’ve heard it on quite a few (even rather expensive) loudspeakers. Enough said? The overall timbre is just spot-on gorgeous, the treble a sheer delight and the neutrality to die for. Listeners wanting thump-thump bass should look elsewhere; these are refined headphones but still capable of fullness and bass weight to complete the realism.

On track after track, that midrange stood out as being so refined and spacious, with hugely pleasant presentation of vocals without sharpness or harshness. I was also delighted to find that voices, and speech material in particular, managed to avoid any of the annoying issues of sibilance, nasality or chestiness and I enjoyed hours of my favourite Poirot mysteries read by David Suchet and the BBC Drama enactments of Lord Peter Wimsey stories starring Ian Carmichael. At no time did I feel that listening via headphones was a compromise over my loudspeakers.

HEDD Heddphone Two headphone review https://the-ear.net

Connecting a Roland UA-25EX USB audio capture unit to my iMac I managed to listen while writing and basked in the delights of a wide range of material. With Flume’s Skin album of electronic tracks, the music flowed so easily, the rhythm maintained across a glorious presentation from this young Australian DJ. There’s a desire, almost a need, via the Heddphone Twos to want to keep on listening in something of an addictive manner. To take in more of those skittish beats on the radio-friendly cuts and loose instrumental interludes. Bass and treble are nicely in proportion and my feet tap away, involuntarily. We are also spared the all-too-common trait of overblown bass in an effort to generate excitement.

The Heddphone Two design scores heavily on technical performance and its glorious midrange timbre. A clearly neutral, precise and accurately resolving sound will see these used by scores of studios. With a very different tuning from the former Heddphone, in the Two we have something that will also appeal to hi-fi users who clamour for neutrality and a faithful reproduction of the recorded material. In my experience too few headphones achieve this in an effort to try and create their own sound signature.

My only gripe is over the headphone cable which is more reminiscent of a 1950s telephone receiver flex than a high-grade headphone lead from the 21st century. However, that can be overcome since the connectors used are an industry standard. The sheer bulk of the unit is another factor, but to use AMT drivers with any effect it has to be this size; at least at the moment but who knows what future technology will bring. Certainly, the Heddphone Twos are comfortable to wear, more so without spectacles, and do not exert undue pressure on the cranium. They are quite a bit lighter than the first-generation design.

HEDD Heddphone Two headphone review https://the-ear.net


Benchmark’s DAC3 HGC arrived at an opportune moment and made a beautiful partnership with the Heddphone Twos. The compact electronics from the USA, proved a great professional coupling and Mindchatter’s debut album, Imaginary Audience. Bryce Connolly’s unique approach to production came across with all of its magic intact; from the alluring vocals which are very three dimensional. He switches from fast-pace house elements to slower stuff to reveal his versatility. We are treated to pensive, almost wistful opening piano chords. backed by synth and eclectic percussion as the album becomes introspective and the passion and emotion shines through vividly via these exquisite headphones. They really are something very special.


On many levels the Heddphone Twos are a winner. They are superbly engineered, those AMT drivers just a delight to listen to, even for prolonged sessions. The build quality is exemplary and, best of all, they are handmade in the German capital and not in some Far East sweatshop.

Sonically, the second-generation of these headphones are a masterpiece in personal listening. The enjoyment factor is enormous and to reproduce the source material with such accuracy is to be applauded. Those who feel they want some hi-fi ‘excitement’ can simply dial-in the appropriate EQ on their headphone amplifier. For me, I love the purity. If these are not a five-star product, I don’t know what is. They are at a very competitive price for such a flagship product. I am not sure I can part with them.


Type: open back planar headphones
Ear coupling: over-ear (circumaural)
Transducer principle: Air Motion Transformer
Driver size: not specified
Sensitivity: 89 dB/1mW
Frequency response: 10 – 40,000 Hz
Maximum SPL: not specified
Distortion THD: not specified
Impedance: 41 Ohms
Cables & connectors: 2.2m headphone cable with 6.35mm termination, 2.2m balanced cable with 4.4mm termination, 3-pin audio adapter – 6.35mm to 3.5mm, 4-pin audio adapter – balanced 4.4mm to XLR
Weight (w/o cable): 550g
Warranty: 2 years (5 with registration)

Price when tested:
Manufacturer Details:

HEDD Audio GmbH
T +49 30 72013470


open back headphones


Trevor Butler

Notify of
Inline Feedbacks
View all comments