Nanyang Technological University

Woon Seng Gan

Ee Leng Tan

Yi Wang

Jun Yang

Khim Sia Tan

Meng Hwa Er

Yew Hin Liew

Furi Andi Karnapi

Chee Mun Kelvin Lee

Kan Sha

A listening device (), such as a pair of headphones, is provided for wearing by a user. It contains two or more sound emitters for directing sound to each ear () of the user. At least one of the sound emitters () is positioned such that sound is emitted in a direction substantially perpendicular to the axis of the ear canal () of the ear, and towards the wall of the concha () of the ear ().

Listening device and accompanying signal processing method

A directional sound system is disclosed. The directional sound system () comprises a plurality of equalization stages () configured to equalize an input signal; and a transducer stage () configured to transmit the equalized input signal; wherein the plurality of equalization stages () comprises a first equalization stage () configured to employ an approximated model of the transducer stage () and a second equalization stage () configured to compensate for differences between the approximated model of the transducer stage () and an actual model of the transducer stage ().

Directional sound system

Apparatus is disclosed for steering a directional audio beam that is self-demodulated from an ultrasound carrier. The apparatus includes means for modulating a carrier signal with an audio signal and means for adjusting the amplitude and phase of at least one of the audio signal and/or the carrier signal to steer the audio beam to a desired direction. The apparatus also includes means for generating an ultrasound beam in the desired direction driven by the modulated carrier signal. The apparatus may include means for weighting the audio and/or carrier signal by a zeroth order Bessel function to synthesize a Bessel distribution source. A corresponding method for steering a directional audio beam is also disclosed. A harmonic generator may be used to generate harmonics of low frequencies in the audio signal. The harmonics may provide (upon demodulation) a psycho-acoustic impression of improved perception of low frequencies. Further, a modulated ultrasonic signal or an unmodulated audio signal may be band-passed into two or more different band-limited signals. The band-limited signals may be amplified and transmitted by ultrasonic transducers having mechanical resonance frequencies substantially equal to a characteristic frequency of the band-limited signals. Ultrasonic processing of the audio signal may include square root methods without generating large numbers of harmonics.

Steering of directional sound beams

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Singapore, Singapore

Woon Seng Gan