Diversity We first validate if FSD reflects the diversity for a set of speech samples and study its
sensitivity to sample size. To achieve that, we design controlled experiments to compute FSD on sets
of samples with varying diversity and sample sizes. Specifically, we create two partitions from 1K
hours of English speech, where each partition has the same set of speakers and the same number of
utterances for each speaker. The first partition is considered the reference set.
To test the sensitivity to sample size, we use the second partition to create subsets by sampling r%
of utterances from each speaker in that partition. This sampling method is denoted as “utt”. We
computed that on average, each speaker contributed approximately 2.33 sessions, with each session
containing around 52.45 utterances. Therefore, the subsets created using the sampling method are
expected to have similar audio style distributions to the reference set and the FSD is expected to stay
Voicebox-Text-GuidedMultilingual UniversalSpeechGenerationatScale