Computational localization of attack regions through a direct observation of the audio waveform.

This article addresses the computational estimation of attack regions in audio recordings. Previous attempts to do so were based on the reduction of the audio waveform into an envelope curve, which decreases its temporal resolution. The proposed approach detects the attack region directly from the audio waveform. The attack region is modeled as a line starting from a low-amplitude point and intersecting one of the local maxima according to two principles: (1) maximizing the slope, while favoring, at the same time, a higher peak if the slope remains only slightly lower and (2) dismissing initial attack regions of relatively low amplitude. The attack start position is fine-tuned by intersecting the attack slope with the audio waveform. The proposed method precisely pinpoints the attack region in cases where it is unambiguously observable from the waveform itself. In such cases, previous methods selected a broader attack region due to the loss of temporal resolution. When attack regions are less evident, the proposed method's estimation remains within the range of results provided by other methods. Applied to the prediction of judgments of P-center localization [Danielsen, Nymoen, Anderson, Câmara, Langerød, Thompson, and London, J. Exp. Psychol. Hum. Percept. Perform. 45, 402-418 (2019)], the proposed method shows a significant increase in precision, at the expense of recall.

Effects of instructed timing on electric guitar and bass sound in groove performance.

This paper reports on two experiments that investigated the expressive means through which musicians well versed in groove-based music signal the intended timing of a rhythmic event. Data were collected from 21 expert electric guitarists and 21 bassists, who were instructed to perform a simple rhythmic pattern in three different timing styles-"laid-back," "on-the-beat," and "pushed"-in tandem with a metronome. As expected, onset and peak timing locations corresponded to the instructed timing styles for both instruments. Regarding sound, results for guitarists revealed systematic differences across participants in the duration and brightness [spectral centroid (SC)] of the guitar strokes played using these different timing styles. In general, laid-back strokes were played with a longer duration and a lower SC relative to on-the-beat and pushed strokes. Results for the bassists indicated systematic differences in intensity (sound-pressure level): pushed strokes were played with higher intensity than on-the-beat and laid-back strokes. These results lend further credence to the hypothesis that both temporal and sound-related features are important indications of the intended timing of a rhythmic event, and together these features offer deeper insight into the ways in which musicians communicate at the microrhythmic level in groove-based music.

Intra- and inter-brain coupling and activity dynamics during improvisational music therapy with a person with dementia: an explorative EEG-hyperscanning single case study.

Objective: Real-life research into the underlying neural dynamics of improvisational music therapy, used with various clinical populations, is largely lacking. This single case study explored within-session differences in musical features and in within- and between-brain coupling between a Person with Dementia (PwD) and a music therapist during a music therapy session. Methods: Dual-EEG from a music therapist and a PwD (male, 31 years) was recorded. Note density, pulse clarity and synchronicity were extracted from audio-visual data. Three music therapists identified moments of interest and no interest (MOI/MONI) in two drum improvisations. The Integrative Coupling Index, reflecting time-lagged neural synchronization, and musical features were compared between the MOI and MONI. Results: Between-brain coupling of 2 Hz activity was increased during the MOI, showing anteriority of the therapist's neural activity. Within-brain coupling for the PwD was stronger from frontal and central areas during the MOI, but within-brain coupling for the therapist was stronger during MONI. Differences in musical features indicated that both acted musically more similar to one another during the MOI. Conclusion: Within-session differences in neural synchronization and musical features highlight the dynamic nature of music therapy. Significance: The findings contribute to a better understanding of social and affective processes in the brain and (interactive) musical behaviors during specific moments in a real-life music therapy session. This may provide insights into the role of such moments for relational-therapeutic processes.