The Göbel Carbon Excellence bending wave loudspeaker
During a period of over fifteen years of engineering and research we created an interna- tional unique and second to none loudspeaker, which reproduce all kinds of sounds in the purest way and reveals really every detail of your favorite music: The Göbel Carbon Excellence bending wave loudspeaker.
This bending wave technology is based on the principals of sound creation through musi- cal instruments and is the element at the heart of each Göbel High End loudspeaker system.
Only the Göbel Carbon Excellence bending wave loudspeaker can eliminate the weak points of a conventional loudspeaker system. You will experience a soundstage with ultra high resolution and speed completely seamless over the entire frequency range that you never heard before. Fine details and textures are reproduced unbelievable naturally without any losses and with the highest possible dynamics.
The music is entirely detached from the loudspeaker, the walls of the room completely disappear and you will find yourself in the middle of a real emotional musical event. Amongst others, the absolutely natural sound reproduction achieved due to the conti- nous bandwidth, the ideal dispersion range and the high dynamic of the Göbel Carbon Excellence bending wave loudspeaker:
The Göbel Carbon Excellence bending wave loudspeaker has a continuous bandwidth from 170 Hz to over 31.000 Hz with one driver! Through this seamless coverage of the entire frequency range all problems with phase and time are completely solved from the outset. In order to obtain such a wide spectrum with conventional loudspeakers, you would have to use at least two special chassis, which undisputable would always cause unintentional phase shifting and non-isochronic dispersion.
Ideal Dispersion Range
The Göbel Carbon Excellence bending wave loudspeaker has a front side dispersion of nearly 180° through the entire bandwidth! Through this seamless coverage of the complete dispersion area, first and foremost, a realistic soundstage is only possible to arise. In addition to this, the backside dispersion reaches up to 4000 Hz which rounds off the realistic soundstage perfectly.
The amplitude of the Göbel Carbon Excellence bending wave loudspeaker is very low, even in the middle frequency range. Therefore the sound reproduction is very dynamic, exact and genuine compared to conventional loudspeakers. In addition to that, the almost non existing mass of the Göbel Carbon Excellence bending wave membrane completely avoids problems caused by mass inertia such as impulse deadening which always occur in conventional loudspeaker systems. The Göbel Carbon Excellence bending wave loudspeaker can therefore, unlike conventional models, reproduce the quickest and most subtle sound impulse absolutely easily and flawlessly. That is why there is no cut in the dynamic, even when listening to music at very low sound pressure levels.
Basic bending wave principles
Wave propagation in solid media
Inducting vibration energy in a solid medium leads to the propagation of different kinds of wave forms: In thicker media, mostly dilatational and longitudinal waves emerge. Surface waves appear on the interfaces between two different surfaces. In thinner media, also transversal waves or bending waves propagate. The velocity of propagation always depends on the inducted frequency. In addition to this, the different wave forms are being influenced by the following parameters:
- the propagation of dilatational and longitudinal waves are dependent on the material constants, which are
determined by the molecular structure, thus the density and the molecular chain.
- the spread of surface waves are subject to the molecular structure of both interfaces.
- transversal waves, where no change of volume or density is connected with the change of wave propagation,
are dependent on elasticity, the specific weight, and the ability to contract transversally.
- in addition to the inducted frequency, bending waves are subject to the bending stiffness (E-module) and
the mass density.
It is only transversal and bending waves that are suited for sound propagation, as they raise a sufficiently high amplitude on a surface.
The basic principle of a bending wave loudspeaker
In order to illustrate the basic principle of a bending wave loudspeaker, the following image is very helpful:
Just imagine you are throwing a stone into a lake! The water surface is being destabilised by this impulse. This shows, as we can witness a wave that propagates equally to each side.
A bending wave loudspeaker is based on the same principle:
A wave front is being raised on a membrane (in our case the water surface) by an electrodynamic motor (in our case the stone). This wave front propagates on the membrane, exactly like the wave front on the water surface. A bending wave has emerged. Due to the changes of air pressure resulting from this wavefront we hear an acoustic tone.
The stiff bending wave loudspeaker
Only a stiff bending wave loudspeaker is qualified for a sound reproduction that features a very broadband frequency / phase linearity, and an impulse fidelity without any sound-focusing effects. As mentioned above, the propagation of bending waves on the membrane is dependent on the frequency that has been inducted. This effect is called the „dispersion of the bending wave“ and it causes a rise of the phase velocity on the membrane while the frequency increases.
The frequency, where the phase velocity on the membrane and the phase velocity in the air are the same, is called „coincidence frequency“. It can be controlled by the bending stiffness (E-Modul) and the mass density.
Göbel bending wave technologies
The basics of the Göbel bending wave technology
An ordinary stiff bending wave loudspeaker bypasses the changes of air pressure, which are being produced by bending waves below this coincidence frequency. This means that the bending wave loudspeaker works only as a normal piston loudspeaker in this range. Above the coincidence frequency the efficiency factor increases by leaps and bounds and the bending wave starts to detach at an angle of > 0 degree.
In contrast to an ordinary stiff bending wave loudspeaker, the GÖBEL bending wave loudspeaker also emits sound by bending waves below the coincidence frequency. The secret of this feature is the special mass density and the damping characteristics of the sophisticated GÖBEL 9-layer membrane. Through our patented membrane, we achieve a very slow transition from a bending wave emitted sound to a piston emitted sound, which results in a perfect around dispersion. This makes it also possible to perfectly integrate an ordinary loudspeaker (e.g. subwoofer). Apart from this, the slow transition cuts off the excursive increase of the efficiency factor.
A GÖBEL bending wave loudspeaker doesn’t only induce a bending wave in a controlled way onto the membrane through the entire frequency range. It also damps the bending wave through the entire frequency range. Because, in a similar way to a wave front reflected on the shore of a lake, a bending wave is being reflected on the membrane. The result: a resounding, diffused and washed-out sound.
The GÖBEL bending wave loudspeaker does not have this problem. Our patented membrane contains three measures to prevent any reflections on edges:
The special bending wave membrane
The basic material of the 9-layered bending wave membrane is produced according to our specifications and consists of a special kind of wood, which contributes through its specific properties (volumetric weight, lignin content, compression strength,...) to the outstanding characteristics of the GÖBEL membrane.
In addition to this, the anisotropy (inhomogeneity) of the wood prevents a distinctive resonance. Our sophisticated procedure of resinating, webbing and compressing the basic material adds to the peerless GÖBEL sound. We only use resin and webbing of best kind and quality, which ensure, in addition to the sound-relevant properties, the best available resistance to ageing and durability.
Through the exact compilation of the webbing layers, the specific measurements of the membrane, the precise adjustments of the heartwood and the physical characteristics of our core material, the amplitude of an emitted bending wave is being constantly damped through its entire runtime on the membrane.
The clampings around the bending wave membrane
The clampings around the edges of the membrane consist of various materials (aluminum, rubber, silicon, foam rubber, PU, ...) to ensure an even limitation of the wave through the entire bandwidth. Through this measure, any reflections on the interface to other media are eliminated through the entire bandwidth, which is more than 7 octaves!
The incisions on the bending wave panel
The laser cut incisions are designed to eliminate any reflections on the edges. Apart from that, the cuttings adjust the stiffness of the membrane. The required geometric angles have to be exactly calculated and precisely executed. In order to reduce production tolerances, the incisions are made with a computer-operated laser. Through this labour-intensive procedure the heartwood is being hermetically sealed and any chipping is being anticipated.
Due to all of these measures, we created a worldwide unique and dynamic loudspeaker, which reproduces all kinds of sound extremely genuine and unveils every detail of your favorite music. Not only the outstanding loudspeakers of GÖBEL High End use the bending wave principle, many instruments like violins, guitars and pianos use it too!
Göbel Carbon Excellence Bending Wave Loudspeaker - The most natural loudspeaker in the world!