Ultra-broadband active noise cancellation at the ears via optical error sensing
share
High frequency noise has been difficult to cancel actively at a person's ears, particularly for active headrest systems aiming to free the listener from noise cancellation headphones. One of the main issues is to measure the noise precisely at the ears. Here we demonstrate a new error sensing methodology with an optical microphone arrangement. It can determine the noise accurately for active noise cancellation (ANC) without any obstructions at the listener's ears. The demonstrated system, or virtual ANC headphone as we call it, can provide more than 10 dB attenuation for the ultra-broadband noise up to 6000 Hz inside the ears in a complicated sound field. Virtual ANC headphones show advantages over other currently known metamaterials and active headrest systems. It has the potential to lead the next generation of personal hearing protection systems and open a whole new area of noise control research.
READ FULL TEXT
