Heilbronn, August 2010: High quality mobile headphones - something audiophiles could only dream about until now. Due to the audio restrictions of smaller, in-ear headphones and general poor acoustics of buses, trains or planes, to date it has been very difficult to achieve high quality audio when using portable headphones on-the-go.
beyerdynamic GmbH is ready to change all of this. The Heilbronn-based audio specialist’s range of new mobile high-end headphones have been designed to offer the most natural and detailed sound available. This has been made possible due to Tesla technology, a revolutionary in-house development by beyerdynamic. Named after the electrical engineer Nikola Tesla, who was born in 1856 in what is now called Croatia, the technology generates magnetic flux density. In other words: it generates a powerful magnetic field which allows the delivery of energy-efficient audio signals via the headphones’ speakers.
As this new Tesla technology delivers such a pure, uncoloured yet refined sound, the use of acoustic gimmicks to emulate larger headphones is not required. Overextended, booming bass and biting treble are not traits that you would associate with the new beyerdynamic mobile T-series.
The engineers chose the name Tesla for a good reason. The pioneer in alternating current and godfather of our modern power supply was fascinated by seemingly unsolvable problems. Thus he was the first to experiment with the wireless transfer of energy and transmitted Morse Code by wireless over many kilometres, years before Guglielmo Marconi and Ferdinand Braun received a Nobel Prize for the invention of wireless telegraphy.
The beyerdynamic T50p mobile headphone, which received the prestigious 2010-2011 EISA Award and the new T5p mobile headphone, which will be introduced at the beginning of September, mirror this pioneering spirit by setting new standards in mobile audio reproduction. As such, they credit the Tesla name and bring to the streets a listening experience that beyerdynamic customers will already be familiar with from the highly-rated T1 model. With one decisive difference: their high efficiency converts as much magnetic power into acoustic energy as possible, making the mobile T-series ideal for MP3 players, notebooks, iPods or iPads.
Mario Gebhardt, Head of Development for audio products at beyerdynamic, explains the special technical aspects of the new type of headphone construction.
What does the term 'Tesla technology' actually mean?
Mario Gebhardt: In beyerdynamic headphones, "Tesla" stands for our latest system technology that is distinguished by a very powerful magnetic drive and sound reproduction free from colouration with a low distortion factor.
What benefits does this drive bring to mobile use?
MG: The additional magnetic power can be converted into acoustic energy, giving the reproduction more power and impact. The mobile Tesla models have a very low impedance 32 Ohm voice coil, which can play particularly loud. In this way, we have an ideal partner for mobile devices with low output power.
How did you achieve this higher magnetic power?
MG: In principle, it was a question of designing a system that permitted the lowest possible degree of loss in magnetic flux. We achieved this with a new type of system geometry that permits us to transfer the magnetic force optimally to the voice coil. Previously, a neodymium magnet was used at the center of the system, and its size was naturally limited inside the headphones. With the Tesla principle, the magnet is mounted as a ring around the coil. This enables us to divert more energy to where it is required: to the membrane.
Is too much sound volume damaging to hearing?
MG: Certainly, but every device has a volume control and with Tesla headphones, you do not have to listen at high volumes. The good thing about a high level of efficiency is that it is also effective at lower volume levels, providing a finer and more elaborate sound. Therefore, we were able to tune out mobile Tesla models very linearly. It does not have a “bathtub” sound as many other mobile headphones do, but reproduces all frequencies just as loudly. The midrange sounds, which are important musically, can be heard with all their detail even at a low volume.
Can the powerful magnetic field lead to health problems?
MG: No, certainly not. The strength of the magnetic field in a headphone system should not be confused with electromagnetic radiation. Inside the headphones, there is a static magnetic field, similar to the earth's magnetic field which is also concentrated upon a tightly limited area: the air gap with the voice coil.
And none of this magnetic field penetrates outside?
MG: Our Tesla systems are indeed optimised so that as little magnetic power as possible escapes from the system, because this would be a loss in efficiency. Naturally, audio signals in the voice coil generate a tiny degree of electromagnetic radiation, as is the case with all headphones. But this is lower than with conventional systems anyway, because the high degree of efficiency requires a very small level of power.
What accounts for the particularly clean sound?
MG: It is the result of many details. What should be specially mentioned is the ring-shaped magnet that allows a central drilling to be positioned immediately behind the centre of the membrane in order to minimise resonances. Apart from that, we use a special multi-level membrane that effectively suppresses unwanted break-up vibrations and consequent distortion.
Why do the Tesla headphones not use noise cancelling?
MG: There are different ways of eliminating ambient noise. We did not choose the electronic method of noise cancelling because our ear pads made from special acoustic foam provide excellent insulation. Unlike with active noise cancelling with out-of-phase sound, users do not experience any pressure on the eardrums at all, there are no background emissions or other unpleasant side effects. With our passive noise cancelling, headphones are lighter, and you do not need to worry about batteries.
Is there a market for such uncompromising mobile headphones?
MG: Admittedly, it does take some audacity to present a headphone like the T5p. These headphones are not for everyone, but are aimed at people who do not want to make any compromises in sound quality when on the go. Traditionally, specialised music listening is done at home. People were willing to lower their standards outside their home. But things are changing. People spend a lot of time travelling, and mobile devices are increasingly replacing the home stereo system. Audiophile demand should not be left behind. We believe the time is ripe for headphones like the T5p. This exceptional headphone brings the pure home listening experience out onto the street - for real high-end sound wherever you are.
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