Early Warning for Target-Speaker Extraction: Reliability under Distribution and Failure-Definition Shift

Shubham Sharma, Manik Gupta


Abstract
Target-speaker extraction (TSE) systems are typically evaluated only after the complete output has been produced, limiting the ability to identify potentially unreliable outputs during generation. We investigate whether failure risk can instead be estimated causally from only the first three seconds of the emitted TSE waveform. We develop an early-warning monitor using 11,946 outputs spanning five conversational corpora and six TSE systems. Because independent failure labels are unavailable for this discovery cohort, we define a proxy adverse outcome from seven complete-output indicators of degraded or atypical TSE behaviour. After excluding monitoring features that overlap with the proxy construction, the monitor predicts this eventual outcome from the early waveform with an AUROC of 0.8062 and an AUPRC of 0.6606. At a 15% review budget, it identifies 54.47% of proxy-adverse outputs with 66.29% precision. To test whether this early-warning signal transfers beyond the discovery setting, we freeze the monitor and evaluate it unchanged on 2,000 unseen outputs with independently computed SI-SDRi. When failure is defined as SI-SDRi ≤ 0 dB, performance falls to near chance (AUROC 0.5354; AUPRC 0.0700). Yet, on the same external outputs, the frozen predictions remain strongly associated with the original proxy outcome (AUROC 0.8092; AUPRC 0.8481). The proxy and SI-SDRi failure definitions agree only weakly ( κ = 0 .028, MCC= 0 .064), while substantial featuredistribution shift is observed between the discovery and external cohorts (45 of 63 features have PSI ≥ 0.25). These results show that short-prefix monitoring can provide useful early risk prioritization within the setting in which the monitor is developed, but that such signals do not automatically transfer to independently defined failure outcomes. Reliable deployment therefore requires explicit attention to both distribution shift and the definition of failure.
Anthology ID:
2026.impactspeech-1.4
Volume:
Proceedings of the IMPACT-SPEECH Workshop: Identifying, Measuring, Preventing, and Assessing Consequences of Bias in Speech LLMs
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Ravi Shekhar, Monorama Swain, Jagabandhu Mishra, Sandipan Dhar, Haralambos Mouratidis, Matthew Purver
Venues:
IMPACT-SPEECH | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
33–41
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URL:
https://aclanthology.org/2026.impactspeech-1.4/
DOI:
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Cite (ACL):
Shubham Sharma and Manik Gupta. 2026. Early Warning for Target-Speaker Extraction: Reliability under Distribution and Failure-Definition Shift. In Proceedings of the IMPACT-SPEECH Workshop: Identifying, Measuring, Preventing, and Assessing Consequences of Bias in Speech LLMs, pages 33–41, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Early Warning for Target-Speaker Extraction: Reliability under Distribution and Failure-Definition Shift (Sharma & Gupta, IMPACT-SPEECH 2026)
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PDF:
https://aclanthology.org/2026.impactspeech-1.4.pdf