An ice-rink lost-child kiosk can speak slowly in a calm voice or quickly in a bright voice. The team keeps the recognizer fixed and only swaps Riva TTS settings, then asks parents which reply they understood. What is the experimental factor?
Select an answer to reveal the explanation.
Short Explanation
Only the speaking voice and pace change; the listening ear stays put. Parents’ understanding is the scoreboard — not a photo metric.
Full Explanation
Holding ASR fixed while swapping Riva TTS voice and rate isolates TTS customization as the experimental factor. Listener understanding is the right score; image metrics, ASR retrains, or text-only summarizers change different parts of the stack.