It seems the world has become obsessed with ‘skinny’ – watch your diet, exercise more and aspire to be ‘model thin’. But skinny isn't always better when it comes to speakers – good sound reproduction needs room to vibrate. However, at IFA, Fraunhofer scientists (in cooperation with Sennheiser electronic) presented a completely new concept for ultra-flat loudspeakers that still deliver full sound reproduction. What’s more, these speakers can be integrated inconspicuously on walls or in furniture because they're only 24mm thick (0.94-inch).

Today, the adage: ‘big sound needs big speakers’ is being increasingly challenged by speaker designers and manufacturers, especially as growing numbers of consumers wish to enjoy big-size movies with theater-style audio, but don’t have the necessary space in which in to do it.

Flat panel loudspeakers appeal to many listeners because they can be appreciated the opposite way to good children – 'heard and not seen'. Scientists at the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau, Germany, together with Sennheiser (the experts in headphone technology), have now developed a special, ultra-flat loudspeaker.

“This new generation offers tonal balance and acoustic pressure at a level that will even allow the use in the professional movie or concert segment in the future,” said Dr Sandra Brix from IDMT. To make this possible, Brix and her team took their inspiration from the loudspeakers of premium headphones.

“We are opening up a new application area for our highest quality electrodynamic headphone miniature loudspeakers in this alliance with Fraunhofer. Because of their compact overall depth, they are excellently suited for use in the flattest loudspeaker boxes, without any losses in tonal persuasiveness,” says Prof Dr Jürgen Peissig, head of the Signal Processing and High Frequency research department at Sennheiser electronic.

“Even if these flat panel loudspeakers are placed directly on the wall or integrated into media equipment or furniture, they can reproduce a frequency range from 100Hz-20kHz,” according to Brix. “This distinguishes our new concept from conventional flat panel loudspeakers that achieve response characteristics at this level only if kept at a certain minimum distance from the wall.”

Consequently, the ultra-flat loudspeakers are ideally suitable for multichannel systems and the IOSONO® audio system. Based on the principle of wave field synthesis, IOSONO produces a realistic and spatial sound field throughout the entire listening area by using a large number of small loudspeakers arranged in a ring.

In the future, Dr Brix says, it will be possible to use this technology in all areas that call for an integration and reproduction of sound as invisible as possible, including the automotive and aircraft construction industries.


  • Reproduction range: 100Hz to 20kHz (-6dB, half-space)
  • Sound pressure level: 88dB SPL/1 W/1m
  • Maximum sound pressure level: 94dB SPL/1m
  • Total harmonic distortion: 5% at 94dB SPL/1m (100Hz to 20kHz)
  • Maximum input power (RMS): 4W
  • Rated impedance: 15Ohm
  • Dimensions

  • Inside: (W/H/D): 700 x 500 x 12mm
  • Outside: (W/H/D): 750 x 550 x 24mm
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