Building high-end headphones which sound so brilliant that you feel that you are in a concert hall; creating acoustics that surpass anything that has been heard before: this has always been Sennheiser's vision. And in 1990/1991, the audio specialist achieved precisely that: Sennheiser took the audio world by storm with an engineering masterpiece that eliminated all previous ideas about the performance limitations of headphones. The Orpheus, an electrostatic headphone system with an impressive 500 V tube amplifier, became an icon of the audio industry and was recognized as the best headphones in the world - until now. Almost 25 years after the legendary Orpheus, in the company's 70th anniversary year, Sennheiser is once again surpassing the limits of what is technically feasible and is opening up a new chapter in audio excellence. The Sennheiser HE 1 represents a unique combination of meticulous engineering skills and technological brilliance. The result: an unprecedented sound experience with the ultimate in reproduction precision and unique spatiality. For seven decades now, Sennheiser has shaped the industry and has been at the cutting edge of audio by continuously re-defining the gold standard of what is technically possible, said Sennheiser CEO Daniel Sennheiser. With the Sennhesier HE 1, we are once again pushing the boundaries and are showing that we can repeatedly set new benchmarks in excellence and reshape the future of the high-end audio world.
In order to craft a successor to the legendary Orpheus as a reference product for the industry itself, Sennheiser worked tirelessly on innovative technical solutions, consistently putting previously used acoustics approaches to the test and exploiting every conceivable possibility when it came to selecting the optimum materials. For almost a decade, a core team of developers, engineers and designers dedicated themselves to producing a successor, and they have now created a headphone system that is beyond comparison. We are very proud of this absolutely exceptional product," said Sennheiser CEO Dr. Andreas Sennheiser. The Sennheiser HE 1 stands for the innovative capabilities of our company and the joint commitment of our workforce to the pursuit of perfect sound.
A patented amplifier concept for incomparable sound
Reproducing sound that is as natural as possible and precise in every detail: with the HE 1, Sennheiser has come closer to this dream than anyone ever before. No other sound reproduction system in the world is able to deceive our senses like the Sennheiser HE 1. It creates the absolutely perfect illusion of being directly immersed in the sound, said Daniel Sennheiser, describing the audio experience. To achieve this, the headphones use a completely new amplifier concept that combines the superior impulse processing of a tube amplifier with the low distortion of a transistor amplifier to perfection.
At the heart of the amplifier are eight vacuum tubes that process the incoming signal. The advantage of tube amplifiers is their superior impulse processing, said Axel Grell, Portfolio Manager Audiophile at Sennheiser. However, one challenge is their sensitivity to air-borne-noise. For this reason, the amplifier housing was crafted from granular, inhomogeneous Carrara marble and is freely suspended with the amplifier. The decoupling of the tubes in combination with the damping properties of the marble has the effect of reducing structure-borne noise to an absolute minimum. The tubes themselves also have a high-quality patent-pending enclosure consisting of quartz-glass bulbs that perfectly shield them from their surroundings.
The tube amplifier stage is followed by a patented ultra-high impulse amplifier stage that is directly integrated into the cups of the headphones. The result is impressive: a 200 percent rise in efficiency compared to other products. In electrostatic headphones, most of the amplifier power is lost in the cable between the headphones and the tube amplifier. Only around one third of the power generated is actually used to produce sound waves, explained Axel Grell. Our approach was therefore to amplify the alternating voltage to high voltages not at the beginning of the cable but at the point where it is really required - directly at the gold-vaporised ceramic electrodes in the headphones themselves. The great advantage of this design is the extremely short distance between the amplifier and the diaphragm, which is less than one centimeter in the Sennheiser HE 1. As a result, the headphone system requires far less power for charge reversal, as the current capacities are much lower. At a voltage of only around 5 Volt, the music signal is transmitted balanced to the high-voltage amplifier integrated into the headphones and is amplified there. This ensures extremely high impulse fidelity with relatively low power requirements. Just like the tubes of the tube amplifier, the system's MOS-FET transistors have a square characteristic curve to prevent the hard distortion that occurs in amplifiers with bi-polar transistors.
Sennheiser places the new amplifier concept in a class that the audio specialist calls Cool Class A. In the low-frequency range, Cool Class A provides Class A power at any volume. In the high- and ultrahigh-frequency range, the amplifier switches from Class A to the usual Class AB operation. That will, however, only be the case when listening to a very unusual frequency spectrum. Cool Class A is a brilliant idea: the music signal is reproduced without distortion and the headphones remain cool, said Axel Grell. We carried out extensive signal analyses and listening analyses as well as detailed tests to find out how much current we need at which frequency in order to achieve this unusual result.
Gold-vaporised ceramic electrodes and platinum-vaporised diaphragms
