Optimization of a Fixed Virtual Sensing Feedback ANC Controller for In-Ear Headphones with Multiple Loudspeakers

TL;DR

This paper presents an optimized fixed multi-loudspeaker active noise control (ANC) controller for in-ear headphones, using a convex optimization approach based on virtual microphone arrangements to enhance noise attenuation.

Contribution

It introduces a convex optimization method for designing fixed multi-loudspeaker ANC controllers using virtual microphone techniques, improving noise reduction over single-loudspeaker designs.

Findings

Multi-loudspeaker VMA controller reduces noise by up to 10 dB below 300 Hz.

Simulation shows improved attenuation compared to single-loudspeaker controllers.

Optimization effectively minimizes sound pressure at the ear drum.

Abstract

In this paper we consider an in-ear headphone equipped with an inner microphone and multiple loudspeakers and we propose an optimization procedure with a convex objective function to derive a fixed multi-loudspeaker ANC controller aiming at minimizing the sound pressure at the ear drum. Based on the virtual microphone arrangement (VMA) technique and measured acoustic paths between the loudspeakers and the ear drum, the FIR filters of the ANC controller are jointly optimized to minimize the power spectral density at the ear drum, subject to design and stability constraints. For an in-ear headphone with two loudspeakers, the proposed multi-loudspeaker VMA controller is compared to two single-loudspeaker VMA controllers. Simulation results with diffuse noise show that the multi-loudspeaker VMA controller effectively improves the attenuation by up to about 10 dB for frequencies below 300 Hz when compared to both single-loudspeaker VMA controllers.