A computationally efficient hybrid 2D\u20133D subwoofer model

Ahmad H Bokhari,Eddie Wadbro,Daniel Noreland,Martin Berggren

doi:10.1038/s41598-020-80092-9

Ahmad H Bokhari, Eddie Wadbro + Show 2 more

Open Access

https://doi.org/10.1038/s41598-020-80092-9

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Abstract

A subwoofer generates the lowest frequency range in loudspeaker systems. Subwoofers are used in audio systems for live concerts, movie theatres, home theatres, gaming consoles, cars, etc. During the last decades, numerical simulations have emerged as a cost- and time-efficient complement to traditional experiments in the design process of different products. The aim of this study is to reduce the computational time of simulating the average response for a given subwoofer design. To this end, we propose a hybrid 2D–3D model that reduces the computational time significantly compared to a full 3D model. The hybrid model describes the interaction between different subwoofer components as interacting modules whose acoustic properties can partly be pre-computed. This allows us to efficiently compute the performance of different subwoofer design layouts. The results of the hybrid model are validated against both a lumped element model and a full 3D model over a frequency band of interest. The hybrid model is found to be both accurate and computationally efficient.

Highlights

The subwoofer is responsible for reproduction of the lowest frequencies in a loudspeaker system
The transducer is mounted in a sealed back chamber and projects into a ported front chamber, which acts as a passive low pass acoustic filter and only allows a band of frequencies to pass through the output port
The passive acoustic filter has the advantage over an electric filter of being placed so that distortion by the transducer can be filtered out

Summary

Introduction

The subwoofer is responsible for reproduction of the lowest frequencies in a loudspeaker system. The model uses linear electrical and mechanical circuit models for the transducer, a stiff approximation of the loudspeaker diaphragm, and linear full-wave air acoustics. Such a model is based on fundamental principles of operation for a subwoofer and serves as a stepping stone for all further work. Displacement-varying stiffness of the diaphragm, magnetic saturation, and the coil leaving the homogeneous region of the magnetic field are examples of nonlinear effects that are more important when leaving the small-signal regime Another effect not considered here is the modal breakup of the cone. Note that all these complications concern the transducer only and not the 2D/3D effects of air acoustics, which is the main concern here

Objectives

Conclusion