This paper explores how the sensation of two active keys, known as key duality or tonal pairing, often results as disjunction between 1) the melody and accompaniment or 2) the bass and upper (SAT) parts. Two of Fauré's late chamber works, the Piano Quintet No. 2 (1921) and the Piano Trio (1923), demonstrate a distinct manner of key duality that arises not as a juxtaposition of two keys but from the superposition of two, à la polytonality. Employing motivic segmentation and voice-leading analysis, I utilize the research of Boyd Pomeroy (2004) and Peter Smith (2013) to illustrate how the impression of two tonal centers emerges when the tonal profile of a melody projects its own center -- separate from that of the underlying accompaniment. Other times, the bass appears divorced from the upper three (SAT) parts; this also results in key duality if the two musical strands express different tonal centers.