Table C5: English TTS duration metrics on LS test-other.

Duration Model
Unconditional Regression
Duration-conditional Regression
Duration-conditional Flow Matching

Phn-MS-MAE Phn-FDD Sil-MS-MAE Sil-FDD

2.53
2.52
2.63

0.72
0.76
0.61

5.32
5.10
5.18

2.39
8.40
2.48

C.4 Duration model evaluation with end-to-end metrics

We now present end-to-end metrics for our three duration variants for zero-shot TTS cross-sentence
and continuation, as well as diverse speech generation, corresponding to Sections 5.2 and 5.5.
Zero-shot TTS cross-sentence and continuation results are shown in Table C8 and diverse speech
generation results in Table C7. These results are not comparable with the main text as they utilize the
flow-matching model described in Appendix B.1, denoted as VB-En-1K.

28

Table C6: English second-half infilling duration metrics on LS test-other.

Duration Model
Unconditional Regression
Duration-conditional Regression
Duration-conditional Flow Matching

Phn-MS-MAE Phn-MS-Corr
Voicebox-Text-GuidedMultilingual UniversalSpeechGenerationatScale