Thin-Film Flexible Acoustic Transducer With Piezo-Electric Properties Used as an Antinoise Speaker for Noise Control

Active noise control has the potential to address the growing problem of Noise pollution. Modern applications of noise control integrate the use of adaptive algorithms and “anti-noise” speakers. This letter explores thin film Polypropylene Ferroelectret being used as an anti-noise speaker for noise control with a focus on the high end of the audible spectrum and ultrasonics (15-40 kHz). The experiments conducted demonstrate the film's ability to cancel or amplify target acoustic noise frequencies, while simultaneously delivering user defined acoustic signals. Noise control is performed, by using Polypropylene Ferroelectret to attenuate/amplify a 10 kHz signal while sustaining a user-defined 5 kHz signal, and vice versa. Additional experiments demonstrate the Polypropylene Ferroelectret material canceling signals from 15 to 40 kHz. The differences in sound pressure levels were measured and used to calculate an effective anti-noise amplitude sound pressure level. These results can be used in the future to compare other potential anti-noise speaker candidates.