Realisation of nonreciprocal transmission and absorption using wave-based active noise control

Nonreciprocal acoustic devices typically break reciprocity by introducing nonlinearities or directional biasing. However, these devices are generally not fully adaptable and often use resonant cavities, which only exhibit nonreciprocal behaviour over a narrow bandwidth. Therefore, to overcome these challenges, this paper investigates how wave-based active control can be used to achieve broadband nonreciprocal behaviour in a one-dimensional environment. Wave-based controller architectures are described for both transmission and absorption control and, through simulation and experimental implementations, it is shown that they can achieve broadband nonreciprocal behaviour. Importantly, the direction of nonreciprocal behaviour can be straightforwardly reversed.