In the long tunnel connecting the 7 train platform to the Bryant Park subway station – a popular spot for buskers owing to the acoustics and the heavy foot traffic – a man is playing what looks to be a hand-carved flute. As is often the case on my morning commute I’m listening to headphones, in this case a song with heavy guitar chords over a minimal skeleton of percussion/base. As I come abreast of the flutist I notice that, improbable as it seems, the trilling of the flute seems to fit perfectly over the guitar music on my iPhone – the two sound sources lock together rhythmically, a floating cloud of notes above a sea of bass and reverb. Are these two sounds actually so perfectly matched, or am I simply imagining their complementarity? In any case this unlikely marriage of sound continues the entire length of the passageway until I descend the stairs to my connecting train.