At the very beginning of the 1990s, Sennheiser, the great German manufacturer of headphones and microphones, presented the most discerning audiophile public with an exceptional pair of headphones called Orpheus. Sennheiser had pulled out all the stops for this project, and brought its entire engineering staff on board. Management had made it clear that price was not an issue. The result was an absolutely exceptional product that still inspires many enlightened enthusiasts to this day. Ladies and Gentlemen, welcome the Sennheiser HE1.
For this second generation, the German manufacturer has once again decided to play the ‘open bar’ card. Sublime right down to its finish, the system consists of electrostatic headphones and an amplifier, both made from luxurious materials. The key technical innovations of this exceptional product include a frequency response above the limits of human perception and the lowest rate of harmonic distortion ever measured for a sound reproduction system. For Sennheiser, there is no doubt that the new Orpheus is the best headphone ever.
We spent a fortnight in the company of the world’s most expensive model. After the initial moments of surprise and amazement, and having fully analysed the technological performance and mechanical challenge represented by such an achievement, we were left with one question: is the HE1 worthy of its reputation? To find out, follow the guide.
For 70 years, Sennheiser has been a pioneer in audio technology and has set the standard for excellence in the industry,’ says Daniel Sennheiser, CEO of Sennheiser. The new Orpheus is a testament to our ability to push the boundaries and reshape the future of the audio industry.
That’s more or less how the HE 1 project was born! We had to offer a worthy successor to the legendary Orpheus, a brand new model that would set a new benchmark in the market. Inevitably, the competition has not been idle for all these years. Add to this the fact that the headphone sector has been by far the most dynamic in terms of growth and creativity for over ten years, and you’ll have understood that the German giant couldn’t sit quietly on its throne.
To achieve this, Sennheiser has worked to develop innovative techniques, constantly questioning its previous acoustic approaches and meticulously selecting each material until it achieves the best result. It took the team of developers, engineers and designers almost a decade to design these superlative performance headphones.
Technological creativity
In broad terms, the technical choices were validated fairly early on. Electrostatic for the headphones, of course, but for the amplifier, it wasn’t quite so simple… In fact, in over 20 years, amplification circuits have progressed considerably. So Sennheiser decided to develop a totally original system. Its tour de force is based on an original amplifier concept, which combines the impulse signal processing quality of a tube amplifier with the low distortion rate of a state-of-the-art transistor amplifier.
The incoming signals are processed by eight tubes.
“Tube amplifiers offer better performance when it comes to processing impulse signals”, explains Axel Grell, Audiophile Product Manager at Sennheiser. “But they are sensitive to ambient noise”.
Sennheiser therefore designed a chassis made of Carrara marble, a material selected for its granularity and heterogeneous structure, which is suspended on the amplifier. The separation of the tubes and the absorption of vibrations by the marble minimise the propagation of noise. Each tube is also isolated from ambient noise by a protective silica glass tube.
The tube amplification stage is linked to a patented ultra-high impulse response amplification stage integrated directly into the headphones’ earcups. According to Sennheiser, this system guarantees 200% better performance than competing solutions. “In an electrostatic system, losses of amplification power on the cable between the headphones and the tube amplifier are common. Generally speaking, only 1/3 of the initial power is actually used to produce the sound waves,’ explains Axel Grell. We have therefore amplified the AC voltage not at the cable input but where it is really needed, i.e. directly at the gold-sputtered ceramic electrodes built into the headphones”.
This configuration considerably reduces the distance between the amplifier and the diaphragms to less than 1 cm. The rated current is therefore significantly limited, which reduces the power required for load reversal. The audio signals are transmitted symmetrically to the high-voltage amplifier built into the headphones, at a voltage of only around 5 V. This configuration guarantees extremely faithful impulse response, despite the relatively low signal power. Like the tubes in a tube amplifier, the Mos-Fet transistors in the system have a non-linear characteristic curve that prevents distortion, which is common in bipolar transistor amplifiers.
The new amplifier is in the class named Cool A by Sennheiser. This guarantees pure Class A power at all volumes in the low frequency range. In the medium and high frequency ranges, the amplifier switches from Class A to classic Class AB. However, this switch only occurs in the presence of an unusually wide range of frequencies.
“Cool Class A is a real step forward. It enables the audio signal to be reproduced without distortion or overheating of the headphone components”, says Axel Grell. “We had to carry out in-depth signal and listening analyses, as well as rigorous tests to determine the right power needed at each frequency level to achieve such a result”.
The head unit is compatible with a wide range of analogue and digital audio sources, thanks to its balanced and unbalanced inputs. It converts incoming unbalanced signals to balanced before processing them. S/PDIF (optical and coaxial) and USB interfaces allow you to connect digital audio sources, whose data will be converted into analogue signals by the ESS SABRE ES9018 chip. The chip’s eight internal DACs convert audio data into 32-bit resolution, with a sampling frequency of up to 384 kHz, or DSD signals at 2.8 MHz and 5.6 MHz into balanced analogue signals. Each stereo channel uses four DACs connected in parallel to optimise noise reduction. This configuration enables the entire frequency spectrum of cutting-edge audio sources to be reproduced without distortion. The circuitry has been optimised for the fully symmetrical design of the Orpheus.
Absolutely exceptional construction
Orpheus is made up of carefully selected materials to maximise the system’s audio quality. Some 6,000 components have been selected after rigorous evaluation for their exceptional and complementary acoustic characteristics. They all contribute to the outstanding audio quality of the new model. In particular, the combination of gold-sputtered ceramic electrodes and platinum-sputtered diaphragms gives the headphones their unrivalled acoustic performance.
“For our electrodes, we were looking for an ultra-rigid material that would minimise distortion peaks in the 3 to 4 kHz frequency range”, explains Axel Grell. The engineers opted for ceramic, a granular material that dampens vibrations much more effectively than glass, for example. But producing such electrodes is no mean feat, as ceramic is particularly difficult to engrave and drill. Sennheiser therefore used a sophisticated grinding and pulverisation process. A layer of gold was then deposited in the vapour phase to optimise electrical conductivity.
The choice of material and process for coating the membranes was equally meticulous. After a long series of tests, the team opted for platinum, also vapour-deposited. The membranes are precisely 2.4 micrometres thick, a size deemed optimal in terms of the ratio of thickness to air density, to control membrane vibrations, according to the results of the developers’ extensive tests. “The aim was not to design the thinnest possible membrane, but to identify the thickness that would give us the best result”, comments Axel Grell.
The Sennheiser team went so far as to design and manufacture the system’s eight high-performance cables themselves, using silver-plated oxygen-free copper to ensure optimum conductivity, which is essential for the quality of audio signal transmission. A sheath made of composite materials with heterogeneous structures insulates the cables from disruptive sound waves.
An unrivalled sound spectrum
With its unique transducer, the new Orpheus offers a frequency response from 8 Hz to over 100 kHz, above the limits of human perception. This amplitude nevertheless has an impact on the sound experience by ensuring that the sound transmitted by the headphones is almost completely free of distortion in the perceptible frequency range.
The system’s rate of harmonic distortion is barely 0.01% at 1 kHz and 100 dB. In other words, it reproduces the sound of the audio source with a level of fidelity and detail unrivalled on the market. Sennheiser thus achieves a degree of audio purity unrivalled by any other audio reproduction system. Even the tiniest nuances become audible. “Listening again to songs that I thought I knew perfectly, I was able to perceive details that I had never heard before”, says Axel Grell of his own experience with the new Orpheus. I was deeply moved, and I’m sure everyone who tries out or uses this unique system will be too. After all, music is about emotion.
The set up
We were lucky enough to be able to use the complete HE 1 system in our auditorium. This allowed us to get to grips with this totally out-of-the-ordinary product. We were able to use it in an environment that we know perfectly well, with reference sources and cables, statutory products that are well up to the standard of excellence of the HE 1: Linn LP 12 turntable with Linn Linto preamp, Atoll DR400se transport, Bricasti M21 streamer converter and Nagra D II digital tape recorder. We had the opportunity to listen to the HEA in good conditions both in Munich and in Paris, but nothing can replace a long listening session at home. To get the best out of the device, we installed it on a Centaure stand and connected it with an Esprit Lumina power cord. For the analogue and digital connections, we carried out various tests with references from Absolue Créations, Actinote, Esprit and JCT.
The sound
Before listening, the HE 1 is already warming up the room by putting on a show. The sight of the front-panel controls slowly emerging from the chassis, of the tubes slowly escaping from the cabinet and beginning to glow, at the same time as the plate covering the headphones swivels, all adds to the pleasure aroused by this elite product.
But let’s face it, the plumage is nothing if not matched by the ramification! Make sure you give the tubes a few minutes to reach thermal maturity, and off you go!
The first thing that strikes you is the feeling that you’re not listening to headphones. Despite weighing in at almost 600g, the headphones don’t weigh your head down and are completely invisible. This comfort guarantees long listening sessions without the slightest excessive pressure on the auricles and the sides of the skull. Listening to headphones offers a very pleasant sensation of ventilation, which, while totally different from listening to speakers, has its strong points. Here, they seem to be multiplied tenfold. The sound space reproduced is in fact of a relatively unprecedented dimension.
When you listen to an opera, you perceive not only the extremely precise dimensions of the room, but also its proportions in terms of height, width and depth. Then there’s the very strong sense of the atmosphere on stage. You can easily identify the place of each performer, the way they move, but also the individuality of each of them. It’s impossible to be penalised by confusion between two of them, because the level of focus of HE 1 is quite simply unique. Unequalled precision and fullness, of course, but also structure and homogeneity in the placement of the different sound planes. Everything is clear-cut and without the slightest approximation. In terms of timbre, there’s nothing to say, or rather: how did they do it? Firstly, the single diaphragm responsible for reproducing all frequencies from the lowest to the highest was clearly the best technical option! Not only is the spectrum reproduced immense, it’s also insanely coherent. The notion of full-range listening has never been more meaningful. It’s great to see that, but technically it’s a hell of a thing to achieve: a single membrane to cover everything is like a ring to rule them all!
The bass is unexpected for headphones: extremely deep, very tight and incredibly powerful. The sound pressure is so great that it’s worthy of certain loudspeakers. Speaking of which, the level at which you can listen with complete fluidity is rare for a system based on circumaural headphones. Across the entire frequency range, the notion of naturalness takes precedence. No register is emphasised. Each is scrupulously organised. The treble rises very high with disarming smoothness. And it’s all the more pleasing because with this model, you can quickly reach totally indecent listening levels. Of course, this isn’t at all annoying for your neighbours, but it can be dangerous for your ears if the system isn’t up to scratch.
Here, there’s nothing to worry about: the distortion simply seems to have disappeared. As long as the signal is of good quality, you can enjoy it to your heart’s content – no dross will penetrate your ear canals. We listened to various styles of music for hours on end, taking advantage of this miraculous opportunity to enjoy this outrageously expensive device at any time of the day or night. We made the most of it, and we have to admit that when we had to put it back in its big wooden case, it left us with a bitter feeling.
Is it worth the price? That’s a complicated question to answer. It’s probably one of the three or four, if not the best headphones on the market. But then, €60,000 is an obscene amount of money. It’s also likely to become an object of speculation. Let’s hope it doesn’t become a social marker. At least for the upper upper upper socio-professional category… I’m convinced that it should be possible to find an exquisite combination of very good headphones from a competing brand and a remarkable headphone amplifier for at least three or four times less. A man like Pierre Paya of Casques Headphones is a master of this kind of subtle combination. But will it be possible to achieve such a degree of operating synergy and manufacturing refinement? Hardly!
Our conclusion
Sennheiser’s aim has always been to create headphones with totally faithful reproduction. It achieved this in 1991 with the Orpheus, a model that became an icon and remains for some the best headphones in the world to this day. The HE 1 is an even more sophisticated model, which has been studied in much greater depth, and which is destined to clearly supplant its predecessor. In our opinion, it succeeds in most respects. It reproduces a wider spectrum of sound. It’s capable of playing much louder with total comfort. Finally, this is the first time we’ve heard headphones with such a low level of distortion, or none at all, if that’s even possible.
The passage of time is cruel when it comes to comparing two products designed almost thirty years apart, especially when it comes to digital technology. After all, both models incorporate a Dac. It therefore seems relatively risky to try and compare them. We had the opportunity to listen to both models. And while it’s true that the first Orpheus has an absolutely extraordinary sound signature and a particular grain in the midrange, it has to be said that its successor goes further in every respect. This in no way detracts from the merit and supremacy over more than
30 years of supremacy.
But finding a first-generation Orpheus second-hand is no mean feat. As for buying the HE1 new, the price seems totally dissuasive.
If there’s one lesson to be learned from this test, it’s that the prodigious R&D that went into creating this product is directly reflected in models that the vulgum pecus like you and me can buy, and that’s the main thing. An HD820/HDV820 set at €4,800 (all the same) is a wonderful combination.
As far as we’re concerned, whether modern beats old is a rearguard action. In terms of pure performance, it’s obvious. But nostalgia is hard-won, and we can understand why the owners of the first Orpheus don’t want to admit it. Finally, it has to be said that there’s a very slim chance that Sennheiser’s engineers, who are all little geniuses, will do less well 30 years later, and even less chance that the company’s hierarchy will accept it. All this to say that the HE1 is in contention for the title of best headphones on the planet. In any case, it’s by far the best Sennheiser ever created.
Technical sheet
- Origin: Germany
- Price: €60,000
HE 1-HP Headphones
- Ear coupling: 4.3 N ± 0.3NP Price : €60,000
- Frequency response: 8 – 80 000 Hz (-3 dB)
- Frequency response: 4 – 100,000 Hz (-10 dB)
- Maximum sound pressure level: 114 dB SPL
- THD: < 0.01% (1 kHz, 100 dB SPL)
- Weight: 550 g (without cable)
HVE 1 tube headphone amplifier
- Maximum output level: 20 dBV
- Frequency response: 5 – 110,000 Hz (-3 dB) 3 – 180,000 Hz (-10 dB)
- THD: typ. 0.01 % (1 kHz, 6 dBV)
- Weight: 21 kg
- Dimensions closed: approx. 434 x 160 x 350 mm
- Dimensions open: approx. 434 x 405 x 375 mm
