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Warwick Audio Technologies reveals FFL

Warwick University spin-off company is working on "sound as you've never seen it". Simon Duff reports

Unusual and innovative loudspeaker design in the UK continues apace with a new groundbreaking technology that resembles tin foil and is less than 0.25mm thick. Developed by University of Warwick spin-off company Warwick Audio Technologies (WAT), the Flat, Flexible Loudspeaker (FFL) can be hung on a wall like a picture, concealed inside ceiling tiles, used in car interiors, or for announcements in public spaces.

Lightweight and inexpensive to manufacture, the technical feature that makes FFL different from other designs lies in the fact that the speaker’s entire surface area radiates in phase. This in turn produces planar directional sound waves giving features such as high directivity and exact sound imaging.

Steve Couchman, CEO of WAT (pictured), has over 30 years of experience in senior/MD positions in the manufacture and distribution of electronics. He believes that FFL could replace many of the speakers currently used in homes and in cars, as well as in public address systems used at passenger terminals and shopping centres.

He says: “We believe this is a truly innovative technology. Its size and flexibility means it can be used in all sorts of areas where space is at a premium. Audiovisual companies are investigating its use as point-of-sale posters for smart audio messaging. In addition, car manufacturers are particularly interested in it for its light weight and thinness, which means it can be incorporated into the headlining of cars, rather than lower down in the interior.”

Explaining how it works he continues: “The FFL speaker produces planar sound waves that project further and are evenly distributed to an audience; the sound levels do not fall away rapidly as you stand further from the speaker. Instead, the sound remains at a more uniform level throughout the audience. Therefore, the speakers are ideal for auditoriums, conference venues, public spaces and presentation rooms.”

In its basic form, the FFL sound panel consists of three or more layers of thin, laminated flexible material. A typical design consists of an insulating sheet sandwiched between two conducting layers. One of these is perforated, allowing air to pass through, while the remaining layers combine as the sound-producing diaphragm. When an amplified audio signal is applied to the metallic layers, electrostatic forces drive the membranes to vibrate, so producing sound. The diaphragm has very little mass, enabling rapid motion without inertia effects. This ensures reproduction of a wide frequency range but in keeping with conventional audio systems, a woofer is required for accurate low-frequency reproduction.

Large sound panels give greater sound levels. The loudest point ahead of a directional panel appears on a line perpendicular to the centre of the panel. WAT says it has achieved SPL levels of 80-105dB, depending on the area of the laminate material selected. Speakers are offered in standard A5, A4 and A3 European paper sizes and can be customised to suit clients with specific unusual applications.

The FFL was first developed by Dr Duncan Billson and Professor David Hutchins from the University of Warwick’s School of Engineering in the department’s Ultra Sonics laboratory.

Early trials were made using just two sheets of tinfoil and an insulating layer of baking paper to produce sound. Since then the design has significantly evolved to its present format and the technology is now ready for commercial exploitation.

Warwick Audio Technologies has been assisted by Warwick Ventures, created in April 2000 to build on the research successes of the University of Warwick. It is responsible for ensuring that the intellectual property that is the result of the university’s annual research spend – some £86 million – is properly protected and commercialised for the benefit of the academics, the university, the region and the nation.

The company is currently in negotiations with a number of commercial partners and continues to welcome fresh approaches. It expects to launch its first commercial product later this year.

To support this, WAT has secured £560,000 of investment out of £800,000 that is required to kick-start an ambitious growth plan. Funding has come from a combination of venture capital and private equity.

The company has filed two patents on what it calls ‘FFL’ technology and conducted an extensive patent clearance/infringement search report, in respect of the company’s intellectual property in Europe and the US. The report concluded “that there would appear to be no patents which are valid and subsisting in the chosen territories which have the identical claims to that of the company’s first and second patents”.

Couchman is both ambitious and determined. He concludes: “Our vision is to be the leading supplier of thin film sound panels in an overall loudspeaker market that analysts are predicting will grow to $4.2 billion in 2010 (source: Oct 2007). To achieve this we will target specific sectors in this market, estimated to be worth $1 billion, where the features of our product provide the most benefits, that is, the markets for audiovisual displays, public address systems, the next generation OLED (organic light-emitting diode) TVs and automotive. Our aim is to create a highly profitable £30 million turnover company within five years.”