Are smart curtain robots loud?

Noise is the single most common complaint in specialist communities. Threads on r/homeautomation describe earlier clip-on motors as loud enough to wake a light sleeper, while r/homeassistant testers note the SwitchBot Curtain 3's QuietDrift mode is genuinely near-silent at the cost of slower travel and faster battery drain. Motorized track systems are generally quieter than clip-on robots but trade installation simplicity for that quiet.