Flat speaker with textile membrane

In the world of Smart Homes and Internet-of-Things, the flat speaker technology is experiencing an upswing. Due to its small depth, it can be used as unobtrusive decor element or integrated almost invisibly into other components. In the ZIM cooperation project “SchallFELT”, the German Institutes of Textile and Fiber Research Denkendorf, together with a speaker manufacturer and the circular knitting company roma Strickstoff Fabrik Rolf Mayer GmbH & Co. KG, created a loudspeaker equipped with a knitted membrane. In combination with a correspondingly designed exciter, a proof-of-concept for a robust flat speaker for reproducing high frequencies – a so-called tweeter – was developed.

The traditional foil magnetostat speaker uses a foil membrane with conductive tracks to create sound. The conductive tracks, applied using vapor deposition, however, are a known weak spot of the speaker. The membrane and the tracks are subject to high forces from the membrane swinging movement when running the speaker. As a result, the conductive tracks tend to detach from the membrane after rather short running times. By using circular knitting, conductive yarns can be integrated permanently in the membrane and function as the conductive tracks for the speaker. Hence, risks of the tracks detaching are eliminated and the lifetime of the speaker is extended. Together with the excitation unit, the developed speaker can create sound waves. After having completed the transition from the proof-of-concept-stage to the prototyping phase, the speaker will be able to play notifications, melodies or other sounds and can be hung on a wall or ceiling. In the long run, the development can be extended to address mid-to-high-frequencies to broaden applications scenarios.

The proof-of-concept demonstrator will be exhibited at TechTextil 2026 in Frankfurt.