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Bayer, Siemens And Puren Produce Speaker-Free Sound System - Pursonic Sound System Turns Walls And Floors Into Speakers (21/6/2004)

When the American jet pilot Charles Yeager broke the sound barrier flying at 1,200 kph on October 14, 1947, it was a global sensation, an unbelievable scientific and engineering achievement. Half a century after this legendary flight, another "sound barrier" has been broken and the results are just as incredible. Welcome to the world of speaker-free sound, where the walls themselves become the speakers. Now you can listen to Handel's Water Music playing from the bathroom tiles while you take a shower, feel the house shake with the footsteps of dinosaurs while you watch "Jurassic Park" on your home cinema system and hear Robbie Williams as if he's literally singing in your living room.

This revolutionary innovation is good news for all home cinema fans. Say goodbye to speakers - now the walls, ceilings and floors produce the sound themselves. The amazing new wall sound system was developed by the polyurethane specialist Puren GmbH, based in †berlingen, Germany, in cooperation with Siemens AG and Bayer MaterialScience AG, one of the largest plastics producers in the world.

Hans Bommer, Managing Director of Puren, on the features of the new sound technology: "The principle of generating sound using a vibrating surface rather than through speakers in the usual way is based on a Siemens patent. The only thing missing up till now was a really good digitally controlled soundboard. Now, after just 18 months of development, we are ready to unveil the complete system."

The heart of the "pursonic" sound technology is a thin soundboard. The element is composed of a special polyurethane made from the Bayer raw materials Desmophen and Desmodur. Eckard Foltin, Head of the Creative Center at Bayer MaterialScience, is always on the lookout for future trends and new applications that can be realized in partnership with Bayer customers: "These materials allowed the thickness of the board to be reduced to seven millimeters. That means it takes up the minimum of space in the wall and is still highly stable." Take the acoustic guitar sound, for example. This also makes the thin outer walls vibrate, but unlike the trumpet it does not generate a strong air pressure wave. So how does it work exactly? Hans Bommer smiles. "Ah well, that's our secret. All I can say is, it took hundreds of attempts to arrive at the sound we were looking for."

Ensuring that the speaker elements still sound good when they have been fitted into walls, ceilings and floors and covered with plaster, carpet or tiles requires high-precision digital technology. That's where Siemens comes in. Every soundboard (five are needed for full, "5.1 surround sound") is made to vibrate by sound generators on the reverse side. These receive signals from a freely programmable digital processor. The art lies in the fine-tuning of the frequencies - treble, mid-range and bass - to the surface material of the wall behind which the soundboard is concealed.

The result is stunning sound quality that is not restricted to a small area (the so-called "sweet spot") as with standard speakers. This is possible because the vibrating surfaces have emission angles almost twice the width of those of standard speakers. And there's another advantage too that's particularly important for presentations - almost no feedback whistle when using a microphone.

Hans Bommer is committed to this audio innovation, and not just since he gave a presentation on it in the United Arab Emirates. "When people first hear about the "pursonic" system they think it must be a gimmick. But as soon as they hear the sound without being able to see any speakers, they want one straight away." While some are excited by the technological features, others also see practical advantages: No more speaker cabinets standing around gathering dust.

Bayer Creative Center Manager Eckard Foltin doesn't let this pragmatism cool his technological ardor. After all, creative vision is part of his job. "Why shouldn't it be possible in future to make the paneling in car interiors produce sound in the same way? Maybe soon we'll have speaker-free car stereos too."

www.pursonic.com