In many of his pieces he layers lyrics, music, and sound recordings over each other. In the short documentary film "Infinita tristeza" (essentially a video travelogue of Chao's 2001 tour of South America), included within the bonus section of his 2002 live DVD release "Babylonia en Guagua", Chao explained that his only recording tool is a small IBM (later Lenovo) ThinkPad laptop computer, which he carries with him wherever he goes; he has occasionally used conventional recording studios, such as Europa Sonor in Paris, to overdub instruments such as drums, electric guitars and brass, but the vast majority of his material (including all sorts of spoken-word samples from radio stations, TV, films, old vinyl records and, on "", announcements from the Madrid Metro) has been recorded by Chao himself exclusively on his laptop. The Spanish credit "Grabado en el Estudio Clandestino" ("Recorded in Studio Clandestino/Clandestine Studio"), which appears on all of his solo album starting from 1998's "Clandestino", actually refers to the laptop.