Multi-Stage Speaker Diarization for Noisy Classrooms

Fuente: arXiv
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Main Authors: Khan, Ali Sartaz, Ogunremi, Tolulope, Attia, Ahmed Adel, Demszky, Dorottya
Format: Preprint
Published: 2025
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author Khan, Ali Sartaz
Ogunremi, Tolulope
Attia, Ahmed Adel
Demszky, Dorottya
author_facet Khan, Ali Sartaz
Ogunremi, Tolulope
Attia, Ahmed Adel
Demszky, Dorottya
contents Speaker diarization, the process of identifying "who spoke when" in audio recordings, is essential for understanding classroom dynamics. However, classroom settings present distinct challenges, including poor recording quality, high levels of background noise, overlapping speech, and the difficulty of accurately capturing children's voices. This study investigates the effectiveness of multi-stage diarization models using Nvidia's NeMo diarization pipeline. We assess the impact of denoising on diarization accuracy and compare various voice activity detection (VAD) models, including self-supervised transformer-based frame-wise VAD models. We also explore a hybrid VAD approach that integrates Automatic Speech Recognition (ASR) word-level timestamps with frame-level VAD predictions. We conduct experiments using two datasets from English speaking classrooms to separate teacher vs. student speech and to separate all speakers. Our results show that denoising significantly improves the Diarization Error Rate (DER) by reducing the rate of missed speech. Additionally, training on both denoised and noisy datasets leads to substantial performance gains in noisy conditions. The hybrid VAD model leads to further improvements in speech detection, achieving a DER as low as 17% in teacher-student experiments and 45% in all-speaker experiments. However, we also identified trade-offs between voice activity detection and speaker confusion. Overall, our study highlights the effectiveness of multi-stage diarization models and integrating ASR-based information for enhancing speaker diarization in noisy classroom environments.
format Preprint
id arxiv_https___arxiv_org_abs_2505_10879
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-Stage Speaker Diarization for Noisy Classrooms
Khan, Ali Sartaz
Ogunremi, Tolulope
Attia, Ahmed Adel
Demszky, Dorottya
Sound
Machine Learning
Audio and Speech Processing
Speaker diarization, the process of identifying "who spoke when" in audio recordings, is essential for understanding classroom dynamics. However, classroom settings present distinct challenges, including poor recording quality, high levels of background noise, overlapping speech, and the difficulty of accurately capturing children's voices. This study investigates the effectiveness of multi-stage diarization models using Nvidia's NeMo diarization pipeline. We assess the impact of denoising on diarization accuracy and compare various voice activity detection (VAD) models, including self-supervised transformer-based frame-wise VAD models. We also explore a hybrid VAD approach that integrates Automatic Speech Recognition (ASR) word-level timestamps with frame-level VAD predictions. We conduct experiments using two datasets from English speaking classrooms to separate teacher vs. student speech and to separate all speakers. Our results show that denoising significantly improves the Diarization Error Rate (DER) by reducing the rate of missed speech. Additionally, training on both denoised and noisy datasets leads to substantial performance gains in noisy conditions. The hybrid VAD model leads to further improvements in speech detection, achieving a DER as low as 17% in teacher-student experiments and 45% in all-speaker experiments. However, we also identified trade-offs between voice activity detection and speaker confusion. Overall, our study highlights the effectiveness of multi-stage diarization models and integrating ASR-based information for enhancing speaker diarization in noisy classroom environments.
title Multi-Stage Speaker Diarization for Noisy Classrooms
topic Sound
Machine Learning
Audio and Speech Processing
url https://arxiv.org/abs/2505.10879