One of Lucier's most important and best-known works is I am sitting in a room (1969), in which Lucier records himself narrating a text, and then plays the recording back into the room, re-recording it. The new recording is then played back and re-recorded, and this process is repeated. Since all rooms have a characteristic resonance (e.g., between a large hall and a small room), the effect is that certain frequencies are gradually emphasised as they resonate in the room, until eventually the words become unintelligible, replaced by the pure resonant harmonies and tones of the room itself. The recited text describes this process in action - it begins "I am sitting in a room, different from the one you are in now. I am recording the sound of my speaking voice...", and concludes with, "I regard this activity not so much as a demonstration of a physical fact, but more as a way to smooth out any irregularities my speech might have," referring to his own stuttering.