High-quality English speech derived from NaturalVoices_VC_870h (JHU SmileLab), restored
with Sidon v0.1 and kept only
where restoration measurably improved perceptual quality (UTMOS gate). Each clip ships
with rich per-utterance metadata (transcript, speaker age/gender, speaking rate, emotion,
and quality scores) so it is ready for TTS / voice-cloning / ASR / paralinguistic research.
