MAD Speech: Measures of Acoustic Diversity of Speech

Matthieu Futeral, Andrea Agostinelli, Marco Tagliasacchi, Neil Zeghidour, Eugene Kharitonov


Abstract
Generative spoken language models produce speech in a wide range of voices, prosody, and recording conditions, seemingly approaching the diversity of natural speech. However, the extent to which generated speech is acoustically diverse remains unclear due to a lack of appropriate metrics. We address this gap by developing lightweight metrics of acoustic diversity, which we collectively refer to as MAD Speech. We focus on measuring five facets of acoustic diversity: voice, gender, emotion, accent, and background noise. We construct the metrics as a composition of specialized, per-facet embedding models and an aggregation function that measures diversity within the embedding space. Next, we build a series of datasets with a priori known diversity preferences for each facet. Using these datasets, we demonstrate that our proposed metrics achieve a stronger agreement with the ground-truth diversity than baselines. Finally, we showcase the applicability of our proposed metrics across several real-life evaluation scenarios. MAD Speech is made publicly available.
Anthology ID:
2025.naacl-long.11
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
222–235
Language:
URL:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-long.11/
DOI:
Bibkey:
Cite (ACL):
Matthieu Futeral, Andrea Agostinelli, Marco Tagliasacchi, Neil Zeghidour, and Eugene Kharitonov. 2025. MAD Speech: Measures of Acoustic Diversity of Speech. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers), pages 222–235, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
MAD Speech: Measures of Acoustic Diversity of Speech (Futeral et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/Ingest-2025-COMPUTEL/2025.naacl-long.11.pdf