Can tension in nontonal music be expressed without dynamic or rhythmic cues? Perceptual theories of tonal harmony predict that psychoacoustic roughness plays an important role in the perception of this tension. We chose a set of orchestrated chords from a nontonal piece and investigated listeners' judgments of musical tension and roughness. Paired comparisons yielded psychophysical scales oftension and roughness. Two experiments established distinct levels ofthese two attributes across chords. A model simulation reproduced the experimental roughness measures. The results indicate that nontonal tension could be perceived consistently on the basis of timbral differences and that it was correlated with roughness, the correlation being stronger as the perceptual salience of other attributes (such as high-pitched tones or tonal intervals) was reduced.An impression of successive tension and release is a common experience while listening to music. The study of this intuitive notion is actually fundamental to Western music theory and has been a matter ofdebate for both music analysts and cognitive psychologists. Whereas many studies have helped us to understand tension perception in the tonal framework, the compositional practices of contemporary composers raise new questions. The use of a musical material that does not draw on the implicitly shared tonal culture may disorient listeners and, hence, deprive them of the essential landmarks that schemas of tension and release provide for the appreciation of a musical work. In this study, we propose to investigate the perception of tension levels for nontonal orchestral timbres by musician and nonmusician listeners. We hypothesized that if tension could actually be perceived in such a context, a basic psychoacoustic dimension known as roughness would account for an important part ofthat perception. Roughness is an auditory attribute that has Part ofthis work was completed thanks to a Fyssen Foundation grant to the first author. The authors thank two anonymous reviewers for extremely useful comments on earlier versions of the manuscript. Correspondence concerning this article should be addressed to either D. Pressnitzer or S. McAdams,