Ultra-broadband local active noise control with remote acoustic sensing

Area of Science:

• Acoustical Engineering
• Signal Processing
• Biomedical Engineering

Background:

• Active noise control (ANC) systems face challenges in acquiring acoustic signals at precise locations for effective sound control.
• Installing microphones in-ear is impractical for applications like ANC headrests.
• Existing virtual error sensing methods often require multiple microphones and head tracking, limiting performance to lower frequencies.

Purpose of the Study:

• To investigate a novel approach for remote acoustic sensing in active noise control (ANC) systems.
• To develop a "virtual ANC headphone" system for localized noise reduction.
• To evaluate the performance of this system in terms of sound attenuation and robustness to head movements.

Main Methods:

• Incorporation of a laser Doppler vibrometer for remote acoustic sensing.
• Development of a lightweight, retro-reflective membrane pick-up placed in the synthetic ear of a head and torso simulator.
• Exploration of membrane design and placement effects on system performance.
• Testing under various sound fields and synthesized environmental noise conditions, including head motion.

Main Results:

• Demonstrated significant sound attenuation of at least 10 dB within the ear canal.
• Achieved effective noise reduction over an extended frequency range (500 Hz to 6 kHz).
• Showcased system performance robustness even during head motion and under complex sound fields.

Conclusions:

• The proposed virtual ANC headphone system offers a practical and effective solution for localized high-frequency noise control.
• Laser Doppler vibrometry provides a viable alternative to in-ear microphones for remote acoustic sensing in ANC.
• The system shows promise for enhancing user comfort in noisy environments by providing personalized noise reduction.