Laptap is a laptop-based, real-time sound synthesis/control system for musicand multimedia performance. The system produces unique sounds by positive audiofeedback between the on-board microphone and the speaker of a laptop com-puter. Users can make a variety of sounds by touching the laptop computer inseveral different ways, and control their timbre with the gestures of the otherhand above the mi, crophone and the speaker to manipulate the characteristicsof the acoustic feedback path. We introduce the basic con, cept of this audiofeedback system, describe its features for sound generation and manipulation,and discuss the result of an experimental performance. Finally we suggest somerelevant research topics that might follow in the future.