Click on the link and select 'Miles' for the one with the black-sounding voice. Speed is as fast as a human convo.
www.sesame.com
Kinda spooky how human-like the responses are.
WATTBA

Crossing the uncanny valley of conversational voice
At Sesame, our goal is to achieve “voice presence”—the magical quality that makes spoken interactions feel real, understood, and valued.

WATTBA