A visualization of music

A dynamic representation of musical rhythm, the multireso-lution analysis using the continuous wavelet transform (CWT), is evaluated using a dataset of the interonset intervals of 105 national anthem rhythms. This representation decomposes the temporal structure of a musical rhythm into time vary-ing frequency components in the rhythmic frequency range (sample rate of 200Hz). Evidence is presented that the beat (typically quarter-note or crochet) and the bar (measure) du-rations of each rhythm are revealed by this transform. Such evidence suggests that the pattern of time intervals, when an-alyzed with the CWT, function as features that are used in the process of forming a metrical interpretation. Since the CWT is an invertible transform of the interonset intervals in each rhythm, this result is interpreted as setting a minimum capability of discrimination that any perceptual model of beat or meter can achieve. It indicates that a bottom-up, data-oriented process (or a non-cognitive model) is able to reveal durations which match metrical structure from realistic musi-cal examples. This then characterises the data and behaviour of a top-down cognitive model which must interact with the bottom-up process.