In the notation of vertical sonorities, it is well-known that composers space chordal tones using wider interval sizes in the bass region. A classic study by Plomp and Levelt (1965) argued that the organization of vertical sonorities in music is related to the phenomenon of critical bands. A replication of Plomp and Levelt's work shows that their demonstration was confounded by an unfortunate artifact and that their results did not support the conclusions drawn. Using a different method, a comparison of actual music with a control sample of "random" music shows that musical practice is consistent with the compositional pursuit of a greater uniformity of spelling with respect to critical bands. Although these results are consistent with conclusions given in Plomp and Levelt, the methods used here avoid the difficulties evident in the earlier study.