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RESEARCH PAPER / 2026-05-18

Flexible Multi-Channel Target Speaker Extraction Using Geometry-Conditioned Spatially Selective Non-linear Filters

Jiatong Li, Wiebke Middelberg, Simon Doclo

Carl von Ossietzky Universität Oldenburg +1 · arXiv

Affiliations: Carl von Ossietzky Universität Oldenburg, German Research Foundation

Abstract

Recently, a spatially selective non-linear filter (SSF) has been proposed for target speaker extraction, using the target direction-of-arrival (DOA) as a spatial cue. Since learned intermediate features are tied to the microphone geometry, the performance of the SSF degrades significantly when evaluated on mismatched array geometries. In this paper, we propose a geometry-conditioned SSF (GC-SSF), which incorporates a geometry-conditioning branch based on FiLM layers. Furthermore, we propose a feature that jointly encodes the DOA and the microphone positions (DOA-MPE). The conditioning branch modulates the intermediate feature maps of the SSF using the DOA-MPE feature to capture the spatial relationship between the microphone positions and the target speaker. Experimental results across circular, uniform linear, and random microphone arrays show that the proposed GC-SSF generalizes better to mismatched geometries while maintaining high spatial selectivity, demonstrating its ability to effectively adapt the filtering process to different array geometries

The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.

Research summary

The main contribution of this paper is the introduction of a geometry-conditioned spatially selective filter (GC-SSF) that enhances target speaker extraction across varying microphone geometries, significantly improving generalization and robustness. This work represents a meaningful step forward in the field of audio processing, addressing a critical challenge with innovative methods and thorough experimental validation.

Methodology

The proposed methodology introduces a geometry-conditioned spatially selective non-linear filter (GC-SSF) that effectively incorporates a geometry-conditioning branch using FiLM layers and a novel DOA-Microphone Positional Encoding (DOA-MPE) feature. This approach addresses the limitations of existing spatially selective filters by allowing the model to generalize across different microphone geometries, which is a significant advancement in the field of target speaker extraction. The integration of positional encoding and conditioning mechanisms is well-justified and demonstrates a thoughtful approach to enhancing the robustness of the extraction process.

Results & evaluation

The experimental setup is comprehensive, utilizing various microphone array configurations (circular, uniform linear, and random) to evaluate the performance of the GC-SSF. The results indicate that the proposed method consistently outperforms baseline systems in terms of generalization across mismatched geometries, with clear metrics provided (PESQ and SI-SDR) to support the claims. The sensitivity analysis regarding target DOA errors further strengthens the findings, showcasing the model's robustness and spatial selectivity.

Reproducibility

The paper provides sufficient details regarding the experimental setup, including datasets, network architecture, and training procedures, which would allow for reproducibility of the results. However, the absence of a public code repository or demo URL limits the ease of access for other researchers to validate and build upon this work.

Limitations

One identified limitation is that the current architecture is designed for a fixed number of microphones, which may restrict its applicability in more dynamic or ad-hoc acoustic environments. Additionally, while the results are promising, the paper does not explore the potential impact of varying environmental conditions beyond the simulated scenarios.

Broader impact

The advancements presented in this paper have significant implications for real-world applications in acoustic signal processing, particularly in environments where microphone configurations may vary. The ability to generalize across different geometries could enhance the performance of speaker extraction systems in various settings, such as conference rooms, public spaces, and smart devices. The main contribution of this paper is the introduction of a geometry-conditioned spatially selective filter (GC-SSF) that enhances target speaker extraction across varying microphone geometries, significantly improving generalization and robustness. This work represents a meaningful step forward in the field of audio processing, addressing a critical challenge with innovative methods and thorough experimental validation.

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