Test-Time Adaptation For Speech Enhancement Via Mask Polarization
Tobias Raichle, Erfan Amini, Bin Yang
TL;DR
The paper tackles the problem of mask-based speech enhancement failing under unseen domain shifts. It introduces Mask Polarization (MPol), a lightweight test-time adaptation method that aligns the distribution of predicted masks to a bimodal reference mask using the Wasserstein distance, without adding model parameters. The approach combines a Wasserstein loss with a nonnegativity penalty and uses continual weight ensembling to stabilize updates, achieving very consistent gains across datasets and architectures and approaching the performance of heavier baselines like RemixIT and CMGAN. This work demonstrates that restoring mask bimodality is a robust, practical signal for adapting SE models in resource-constrained settings, bridging ideas from classification adaptation to audio tasks and enabling practical edge deployment.
Abstract
Adapting speech enhancement (SE) models to unseen environments is crucial for practical deployments, yet test-time adaptation (TTA) for SE remains largely under-explored due to a lack of understanding of how SE models degrade under domain shifts. We observe that mask-based SE models lose confidence under domain shifts, with predicted masks becoming flattened and losing decisive speech preservation and noise suppression. Based on this insight, we propose mask polarization (MPol), a lightweight TTA method that restores mask bimodality through distribution comparison using the Wasserstein distance. MPol requires no additional parameters beyond the trained model, making it suitable for resource-constrained edge deployments. Experimental results across diverse domain shifts and architectures demonstrate that MPol achieves very consistent gains that are competitive with significantly more complex approaches.
