The concept of dynamical form is presented as a dimen- sion of music perception. Dynamical form refers to the subjective perception of temporal events in music (explo- sive, fading out, rising etc.). In a behavioral experiment listeners were asked to categorize musical excerpts vary- ing in musical period, tonality, instrumentation, and acoustic features while attending to their dynamical form. Data indicates that subjects are sensitive to dynamical forms, but were particularly sensitive to a specific one (suspense). We also discuss a method of categorizing dynamical forms in terms of force dynamics.